Anil - Limbs by ICSM SU

Anatomy of the Limbs LCRS Year 2 Anil Chopra

Contents Contents..........................................................................................................................1 Limbs 1a - Bone Growth, organisation and repair.........................................................2 Limbs 1b - Overview of Anatomy of Upper and Lower Limbs.....................................7 Limbs 2 – Shoulder and Arm.......................................................................................12 Limbs 3 – Elbow, Forearm and Wrist..........................................................................26 Limbs 4 – Hand............................................................................................................35 Limbs 5 – Brachial Plexus............................................................................................44 Limbs 6 - Hip, Buttock and Thigh...............................................................................46 Limbs 7 – Knee, Popliteal Fossa, Leg and Foot...........................................................60 Limbs 8 - Lower limb Nerves and Vessels..................................................................78 Injury to the Femoral Nerve.................................................................................79 Cannulation of the femoral artery and vein..................................................................80 The concept of arterial embolism.................................................................................81 Varicose veins and deep venous insufficiency.............................................................82 Deep venous thrombosis..............................................................................................82 The superficial veins as grafts in elective surgery.......................................................82

Limbs 1a - Bone Growth, organisation and repair Anil Chopra 1

Outline the process of longitudinal growth of long bones making appropriate use of the following terms: cartilage model; primary ossification centre; diaphysis; secondary ossification centre; epiphysis; epiphyseal plate; calcification; vascularisation; ossification 2 Suggest possible advantages of epiphyseal growth over simple appositional growth at the bone extremities. 3 Suggest reasonable dates for the appearance of primary and secondary centres of ossification for long bones. 4 Recognise ossification centres in radiographs of growing limbs and use this information to estimate the age of a child. 5 Explain how bones grow in diameter and are remodelled. 6 Describe the sequence of events in the repair of a fracture. 7 List the main risk factors for fracture of the femoral neck. 8 Identify anatomical and other factors that may compromise satisfactory repair of fractures of the femoral neck. 9 Explain the principles of management of simple fractures of limb bones. 10 List the main dangers of limb fractures and of their mismanagement. Functions of Bone: - support - storage of minerals - protection - levers for movement - site of blood cell production Types of Bone: Woven – immature, in growing skeletons or in fractures. Weaker and more flexible than lamellar bone. Lamellar - mature, in normal skeletons. There are two types (usually arranged as layers – compact on the outside and cancellous on the inside): - Cortical (compact): 80% of skeleton, high resistance to torsion and bending. Normally on the outside of the lamellar bone. Here the functional unit is the Haversian system, which has osteocytes round the outside and a Haversian canal on the inside. They are arranged into concentric layers of matrix called lamellae. - Cancellous (trabecular): less dense, spicules of marrow in between; has high turnover rate. Normally on the inside of the lamellar bone. There are no lamellae in cancellous bone, only a network of rods called trabeculae. Adaptability in Bone:  Can grow without compromising its support functions – redundancy  Increases or decreases bulk and density in response to pattern of use  Can alter its shape both internally and externally in response to the pattern of use – remodelling  Can repair when fractured 2

Cells in Bone Osteocytes: mature bone cells that lie within a lacunae (each lacunae contains one osteocyte). The lacunae are connected by canaliculi. Their role is to maintain bone matrix and repair bone. When bone is damaged, osteocytes are no longer bound to the lacunae and so they differentiate into osteoblasts and osteoprogenitor cells. Osteoblasts: produce bone matrix. They eventually become osteocytes. Osteoprogenitor cells: stem cells that differentiate into osteoblasts. Involved in fracture and repair. Osteoclasts: (giant cells) remove bone matrix. They are derived from monocytes. This results in a constant turnover of bone matrix with the osteoblasts producing bone and the osteoclasts removing bone. This is known as remodelling and occurs as a result of different physical stresses put on the bone. Around 20% of the adult skeleton is remodelled each year. Bone Matrix The combination of substances in the bone matrix gives bone its mechanical properties. It consists of: Collagen fibres: strong, flexible, good at resisting tension, twisting, bending, and provide a lattice for the hydroxyapatite crystals. They are not good for resisting compression. Inorganic Ions: mainly calcium phosphate, calcium hydroxyapatite, and calcium hydroxide. The calcium phosphate crystals are hard but inflexible and brittle but good at resisting compression.

Periosteum The periosteum is a thin layer of dense, irregular connective tissue membrane that covers the outer surface of a bone in all places except at joints. The outer layer is fibrous and the inner layer is cellular. Its job is to protect the bone from the surrounding tissues and also allows blood vessels and nerves into the bone. It is also very important for growth and repair. Endosteum The endosteum is a thin layer of connective tissue which lines the surface of the bony tissue that forms the medullary cavity (or marrow cavity) of long bones. It is very active in bone growth and repair. Blood Supply in Bones Periostial Arteries: enter bone via the periosteum. Stripping the periostium in a fracture can result in disruption of the blood supply from the bone and can also lead to bone infection and death. Nutrient Arteries: enters near the middle of the bone, passing obliquely through the cortical bone and supplies the cancellous bone. Metaphyseal and epiphyseal arteries: supply the ends of the bones. These are only present in a growing skeleton. Nerve Supply to Bones The periosteum that surrounds bone is richly innervated with sensory (pain and proprioception) fibres. The blood vessels going to bone also have sympathetic supply. Growth of Bones Bones grow from the 6th week of foetal life until 25 years of age. They grow via two different processes: Intramembranous Ossification This forms directly from the mesenchyme, an embryonic connective tissue. It occurs mainly in bones that are directly beneath the skin e.g. skull, mandible and clavicle. It occurs as follows:  Mesenchymal cells produce bone matrix (osteoid) containing collagen.  Osteoid becomes mineralised with calcium salts.  Cells in the mesenchyme differentiate into osteoblasts.  These produce more matrix.  Some osteoblasts get trapped in lacunae and become osteocytes.  Blood vessels grow and maintain blood metabolism.  This forms cancellous bone  The cancellous bone eventually remodels into cortical bone.  Periosteum forms around the bone and traps the surface layer of osteoblasts

Endrochondral Ossification Most long bones ossify in this way and it involves the mesenchymal cells forming cartilage and then the cartilage ossifying. This allows them to support large forces while growing:  Mesenchymal cells differentiate into chondroblasts (cells which form cartilage).  These chondroblasts make cartilage models of the bone which expand by expansion of the cartilage matrix.  In the middle of the bone the chondrocytes die as the cartilage is increasingly calcified and capillaries from the periosteum penetrate to the centre forming a periosteal bud.  This differentiates into osteoblasts and forms a primary ossification centre.  This grows outwards forming a diaphysis. Appositional growth increases the diameter of the diaphysis.  Secondary ossification centres form at the epiphyses (ends) of the bone, usually around 2 years after birth. The area between the diaphysis and the epiphyses is the epiphyseal plate.  The bone grows by adding at each epiphysis and only stops when the epiphyses meet the diaphysis.  This growth stops at puberty (increased hormone levels stop growth)

NB: calcification is not the same as ossification, ossification is vascular, calcification is not. Growth in bone diameter:  Apposition – addition to the exterior of the periosteum  Osteoblasts and osteoclasts produce ridges and grooves on bone surface  Blood vessels align in grooves  Osteoblasts build new osteons around blood vessels  Osteoclasts remove bone from endosteal surface

Fracture Repair 1) When bones are damaged, the vessels rupture producing a vessel haematoma. 2) Active osteoblasts and osteoprogenitor cells migrate toward the fracture. 3) They form a type bone and cartilage called external callus which bridges the ends of the bones and internal callus which forms between the bone ends. 4) Chondrocytes produce cartilage, which is calcified to woven bone and then cancellous bone, which eventually remodels into cortical bone (via osteoblasts and osteoclasts). Bone Remodelling:  Bone is not dead, it is continually remodelling  Process of remodelling mirrors bone growth and repair after fracture  It is affected by physical stresses placed on the bone and metabolic and hormonal factors  20% of the adult skeleton is remodelled every year

Limbs 1b - Overview of Anatomy of Upper and Lower Limbs Anil Chopra 1 2 3

Explain briefly the embryological development of the limbs Outline briefly the similarities and differences in the upper and lower limbs Explain briefly the difference between the segmental and peripheral nerve supply of a limb 4 Describe the essential structure of the upper and lower limbs, noting the compartmentalised nature of the limbs and their neurovascular supply 5 Outline the muscular compartments of the upper limb 6 Describe the neurovascular patterns of the upper limb 7 Outline the muscular compartments of the lower limb 8 Describe the neurovascular patterns of the lower limb 9 Explain the neurological components of neurological supply to a limb: motor, sensory, reflex, autonomic and trophic 10 Describe a method whereby the neurological features of nerve injury can be evaluated using the pattern described above. Embryology of the Limbs The limbs grow out of the trunk along with the nerves that are going to supply them (C5-T1 for the arms and L2-S2 for the legs). The upper limbs do not rotate. The lower limbs however undergoes extension and internal rotation. Upper limb –  flexors are anterior  extensors are posterior Lower Limb –  Extensors are anterior  Flexors are posterior The limbs pick up their nerve supply before rotation Compartments of the Limbs Muscles in the same compartment tend to perform the same role and have similar blood and nerve supplies. Upper Limb: 1. Pectoral girdle muscles (chest) 2. Intrinsic shoulder muscles 3. Anterior upper arm muscles - flexors 4. Posterior upper arm muscles - extensors 5. Anterior forearm muscles - flexors 6. Posterior forearm muscles - extensors 7. Intrinsic hand muscles Lower Limb: 1. Hip abductors 2. Hip extensors 3. Hip flexors 4. Anterior thigh muscles - extensors 5. Medial thigh muscles 7

6. Posterior thigh muscles - flexors 7. Anterior leg muscles - extensors 8. Lateral leg muscles 9. Posterior leg muscles - flexors 10. Intrinsic foot muscles Blood Supply to the Limbs Upper Limb:  Aorta  Subclavian artery  Axillary artery (as it passes into the limb) – has many branches.  Brachial artery (as it enters the upper arm) – this then splits into the: o Ulnar artery  Common interosseous artery • Anterior interosseous artery • Posterior interosseous artery o Radial artery o Anastomosis  Palmar carpal arch  Dorsal palmar arch  Metacarpal arteries  Digital arteries  Veins generally follow the arteries  There are 2 systems: superficial and deep o Superficial system = cephalic and basilic vein which arise from the dorsal venous arch on the back of the hand o The basilic vein runs on the medial (ulnar) aspect of the forearm and passes deep halfway to form the axillary vein o The cephalic vein runs superficially on the lateral (radial) aspect of the forearm and upper arm and passes deep at the level of the shoulder to form the axillary vein o Deep forearm veins pass from the forearm and drain into the basilic vein  Venae comitantes pass alongside the brachial artery in the upper arm and drain into the axillary artery  The axillary vein passes from the upper arm into the axilla being a continuation of the basilic vein where the cephalic and vena comitantes drain into it→ subclavian vein  During cold weather venous drainage is through deep veins  During hot weather venous drainage is through superficial veins Lower Limb:  Common iliac arteries o Internal iliac artery o External iliac artery  Femoral artery  Profunda femoris artery o Superficial femoral artery o Popliteal artery 8

 Posterior tibial artery  Anterior tibial artery  Peroneal artery o Plantar arch  In the leg there are also superficial and deep venous systems  Deep veins in the calf form the popliteal vein at the back of the knee → forms the superficial femoral vein which runs alongside the superficial femoral artery → joined by the venae comitantes to form the femoral vein → passes beneath the inguinal ligament to form the external iliac vein → inferior vena cave  Superficial veins start as the dorsal venous arch → long saphenous vein arises from the medial aspect of the dorsum of the foot just anterior to the medial malleolus and runs up the medial sside of the limb, joining the femoral vein in the groin. The short saphenous vein arises from the lateral aspect of the dorsal venous arch, runs up the back of the leg and joins the popliteal vein in the back of the knee Nervous Organisation of the Limbs The innervation from the limbs comes from spinal nerves: o C5 – T1 for the arms o L2 – S2 for the legs Nerves form plexi of which in the:  Upper limb: anterior division supply the flexors and the posterior division supply to the extensors  Lower limb: posterior division supply the flexors and the anterior division supply the extensors Segmental Innervation - Muscles are generally supplied by two adjacent segments of the spinal cord. - Muscles with the same action share the same nerve supply. - Opposing muscles are usually supplied by nerves two segments above or below. - The more distal (outward) the joint in the limb, the more caudal (lower) the spinal segment controlling that. The Upper Limb The Upper Limb Shoulder Elbow Forearm Wrist Long tendons to hand Intrinsic hand muscles

Abduction Adduction External Rotation Internal Roatation Flexion Extension Supination Pronation Flexion Extension Flexion Extension

C5 C678 C5 C678 C56 C78 C6 C78 C67 C67 C78 C78 T1

The Lower Limb Lower Limb Hip L2 L3 L4 L5 S1 S2

Knee

Ankle

Flexion Extension Extension

Dorsa Flexion Flexion Planta Flexion

Sensory Segmental Supply Each segmental spinal nerve supplies sensation to a strip of skin. These do generally overlap – so when a single dermatome is lost it is not generally noticed. • C4 – infraclavicular region • C5 – lateral arm Segmental Sensory Supply of the • C6 – lateral forearm and thumb lower limb • C7 – middle finger • C8 – little finger and medial forearm • T1 – medial arm • T2 – axilla and trunk • T4 – nipple • T10 – umbilicus • T12 – lower abdomen • L1 – suprapubic region • L3 – front of the thigh (L3 to knee) • L4 – front of leg (L4 to floor) • L5 – dorsum of great toe • S1 – lateral aspect of foot • S2-S4 – perineum and perianal region  



Segmental Reflexes: Either stretch reflexes or deep tendon reflexes and are monosynaptic Two main reflex arcs in the upper limb:  Biceps jerk (C6)  Triceps jerk (C7) Two main reflexes in the lower limb:  Knee jerk (L3)  Ankle Jerk (S1)

Autonomic segmental supply to the limbs: • Sympathetic supply via T2-T6 for upper limbs and T11-L2 for lower limbs • No significant parasympathetic outflow to the limbs Peripheral Nerve Supply to the Limbs: • Peripheral innervation of the upper limb is derived from the brachial plexus which is from the anterior rami of C5-T1 of the spinal nerves

• •

Peripheral innervation of the lower limbs is from the lumbro-sacral plexus which is derived from the anterior rami of L2-S2 Most peripheral nerves are mixed, containing motor and sensory fibres.

Limbs 2 – Shoulder and Arm Anil Chopra 1.

Name the bones and joints of the upper limb from the shoulder girdle to the elbow. 2. Demonstrate the main movements of the shoulder girdle, shoulder joint and elbow 3. Identify in a living subject and in appropriate imaging; a. the clavicle and its sternoclavicular and acromioclavicular joints b. the lateral and medial borders and inferior angle of the scapula, the scapular spine, acromion process, coracoid process and glenoid fossa 4. Name and demonstrate the position, main attachments and actions of; a. pectoralis major b. latissimus dorsi c. trapezius d. serratus anterior e. teres major f. deltoid 5. List the spinal nerve roots supplying the upper limb 6. Demonstrate the position and boundaries of the axilla 7. Understand the general arrangement of the brachial plexus. 8. Demonstrate how the major nerves and vessels of the upper limb reach and enter the axilla 9. Explain the significance of the term “synovial ball-and-socket joint” using the shoulder joint as an example 10. Summarise the main factors stabilising the shoulder joint 11. Explain how the stability of the shoulder joint fails in dislocation 12. Discuss the difference between acromioclavicular dislocation and shoulder joint dislocation 13. Explain the risk to the axillary nerve in shoulder dislocation and the likely consequences of injury to this nerve and demonstrate how the function of this nerve can be assessed 14. Describe the rotator cuff arrangement of muscles and tendons and explain why the rotator cuff is important in shoulder function and is clinically a common site of pathology. Outline the importance of imaging of the shoulder in rotator cuff problems. Describe clinical testing of the rotator cuff 15. Explain the anatomical basis of frozen shoulder. 16. Outline the main areas supplied by important branches of the subclavian and axillary arteries and explain the importance of the anastomosis among these branches 17. Explain what is meant by winging of the scapula and its anatomical basis. Bones of the Region Clavicle: the collarbone. The clavicle is the only bony attachment between the trunk and the upper limb. It is palpable along its entire length and is an S-shaped contour. The acromial end is flat, 12

whereas the sternal end is more robust and quadrangular in shape. The acromial end has a small oval facet on its surface for articulation with the medial end of the acromion of the scapula. The sternal end has a larger facet for articulation with the manubrium of the sternum. The inferior surface of the lateral third of the clavicle possesses a tuberosity containing the conoid tubercule and trapezoid line. It is the first bone to ossify in utero and does so by intramembranous ossification. Scapula: a large flat triangular bone with: • three angles (lateral, superior, and inferior); • three borders (superior, lateral, and medial); • two surfaces (costal and posterior); and • three processes (acromion, spine, and coracoid process) - The lateral angle is marked by the glenoid cavity (articulates with the head of the humerus – glenohumeral joint). - The large triangular shaped roughening (the infraglenoid tubercule) inferior to the glenoid cavity is the site of attachment for the long head of the triceps brachii. - The supraglenoid tubercule is the site of attachment of the long head of the biceps. - The prominent spine divides up the posterior surface (into infraspinous and supraspinous).

The acromion (Greek = acromius meaning summit) is an anterolateral projection of the spine articulates with the clavicle. - The lateral border is thick and strong as it is used for muscle attachments. - The superior border is marked on its lateral end by: o Coracoid process: look like structure o Suprascapular notch NB: the spine and coracoid process are easily palpable Proximal Humerus: the hind bone of the arm. The head is a half-spherical shape and projects medially and somewhat superiorly to articulate with the much smaller glenoid cavity of the scapula. There are 2 tubercles (greater and lesser) that are prominent landmarks for attachment sites for rotator cuff muscles: Greater Tubercle: - Supraspinatus - Infraspinatus - Teres minor Lesser tubercle: - Subscapularis. It is important to note the surgical neck because the neck is weaker than the proximal regions of the bone, fractures are common there. The associated axillary nerve and posterior circumflex humeral artery can be damaged by fractures here. Joints Sternoclavicular: this is the only real bony joint between the upper limb and the rest of the body. This is between the medial end of the clavicle and the clavicular notch on the manubrium of the sternum and the first costal cartilage. It is synovial and is held in place by 4 ligaments. - anterior sternoclavicular ligament - posterior sternoclavicular ligament - interclavicular ligament - costoclavicular ligament These ligaments make it particularly strong joint. It allows for movement of the clavicle mainly in the anteroposterior and vertical planes although some rotation occurs. It is surrounded by a joint capsule and articular disc and can be damaged resulting in sternoclavicular subluxation and dislocation. Acromioclavicular: small synovial joint between the acromion of the scapula and the acromial end of the clavicle. It is held together by: 14

acromioclavicular ligament – minor dislocations occur when this ligament is torn coracoclavicular ligament – important as is provides most of the weightbearing support for the upper limb on the clavicle and maintaining the position of the clavicle on the acromion. Major dislocations occur if this ligament if torn. coraco-acromial ligament

It allows for movement in the anteroposterior and vertical planes together with some axial rotation. This is often injured by falls onto an outstretched hand (ligaments are torn). Glenohumeral: the shoulder joint. It is a synovial “ball and socket” joint between humerus and glenoid process of the scapula. It allows for great mobility at the expense of stability (any stability comes from the ligaments rather than the articulation itself) . It is very shallow and the head of the humerus lies in the glenoid labrum which is a fibrocartalaginous collar which attaches to the margin of the fossa.

The capsule of the glenohumeral joint can protrude through the holes in the fibrous membrane that surrounds the joint forming bursae (a fluid filled sac): - the subacromial bursa (between the humeral head and the acromial process – often a site of pathology for shoulder interference) - the subtendinous bursa of subscapularis (between the subscapularis muscle and the fibrous membrane) - the synovial sheath that extends along down the long head of the biceps brachii. The coraco-acromial arch lies above the shoulder joint and stops the humerus rising superiorly against the acromion. It is held in place by the rotator cuff muscles and stabilised by a number of ligaments:  Gleno-humeral ligaments – strengthen the anterior portion of the shoulder capsule  Coraco-humeral ligament – strengthens the capsule superiorly  Transverse humeral ligament – holds the tendon of the long head of biceps in the inter-tubercular groove Scapulo-thoracic: movements of the scapulo-thoracic joints are important and occur mainly when the arm is abducted more than 90°. It is a theoretical concept but allows for certain sorts of movement. The main movements are:  Elevation and depression of the scapula  Protraction of the scapula – forward and lateral movement against the chest wall  Retraction – backward and medial movement against the chest wall  Rotation of the scapula Muscles of the Region Muscle Origin Insertion Innervation Function Anterior Pectoral Muscles Pectoralis major Clavicular head-anterior Lateral lip of inter- Medial and lateral Flexion, adduction, and surface of medial half of tubercular sulcus of pectoral nerves; medial rotation of arm at clavicle; sternocostal head- humerus clavicular head gleno-humeral anterior surface of sternum; [C5,C6]; joint;.clavicular headfirst seven costal cartilages; sternocostal head flexion of extended arm; sternal end of sixth rib; [C6,C7,C8,T1] sternocostal head- extension aponeurosis of external of flexed arm oblique Subclavius First rib at junction between Groove on inferior Nerve to Pulls tip of shoulder down; rib and costal cartilage surface of middle subclavius pulls clavicle medially to one-third of clavicle [C5,C6] stabilize sternoclavicular joint Pectoralis minor Anterior surfaces and Coracoid process of Medial pectoral Pulls tip of shoulder down; superior borders of ribs III to scapula (medial nerve [C6,C7,C8] protracts scapula V; and from deep fascia border and upper overlying the related surface) intercostal spaces Serratus anterior Lateral surfaces of upper 8-9 Costal surface of Long thoracic Protraction and rotation of ribs and deep fascia medial border of nerve [C5,C6,C7] the scapula; keeps medial overlying the related scapula border and inferior angle of 16

intercostal spaces Posterior Pectoral Muscles Levator Transverse processes of CI scapulae and CII vertebrae and posterior tubercles of transverse processes of CIII and CIV vertebrae

scapula opposed to thoracic wall Posterior surface of Branches directly Elevates the scapula medial border of from anterior rami scapula from of C3 and C4 superior angle to root spinal nerves and of spine of the by branches [C5] scapula from the dorsal scapular nerve Floor of Thoracodorsal Adduction, medial rotation, intertubercular sulcus nerve [C6,C7,8] and extension of the arm at the glenohumeral joint

Latissimus dorsi Spinous processes of lower six thoracic vertebrae and related inter-spinous ligaments; via the thoracolumbar fascia to the spinous processes of the lumbar vertebrae, related interspinous ligaments, and iliac crest; lower 3-4 ribs Rhomboid Lower end of ligamentum Posterior surface of Dorsal scapular minor nuchae and spinous processes medial border of nerve [C4,C5] of CVII and TI vertebrae scapula at the root of the spine of the scapula Rhomboid Spinous processes of TII-TV Posterior surface of Dorsal scapular major vertebrae and intervening medial border of nerve [C4,C5] supraspinous ligaments scapula from the root of the spine of the scapula to the inferior angle Trapezius Superior nuchal line, external Superior edge of the Motor spinal part occipital protuberance, crest of the spine of of accessory nerve medial margin of the the scapula, (CN XI). Sensory ligamentum nuchae, spinous acromion, posterior (proprioception) processes of CVII to TXII border of lateral one- anterior rami of and the related supraspinous third of clavicle C3 and C4 ligaments Intrinsic Shoulder Muscles Supraspinatus Medial two-thirds of the Most superior facet Suprascapular supra-spinous fossa of the on the greater nerve [C5,C6] scapula and the deep fascia tubercle of the that covers the muscle humerus Infraspinatus Medial two-thirds of the Middle facet on Suprascapular infra-spinous fossa of the posterior surface of nerve [C5,C6] scapula and the deep fascia the greater tubercle that covers the muscle of the humerus Teres minor Upper two-thirds of a Inferior facet on the Axillary nerve

Elevates and retracts the scapula

Powerful elevator of the scapula; rotates the scapula during abduction of humerus above horizontal; middle fibers retract scapula; lower fibers depress scapula Rotator cuff muscle; initiation of abduction of arm to 15° at gleno-humeral joint Rotator cuff muscle; lateral rotation of arm at the glenohumeral joint Rotator cuff muscle; lateral 17

Teres major

flattened strip of bone on the posterior surface of the scapula immediately adjacent to the lateral border of the scapula Elongate oval area on the posterior surface of the inferior angle of the scapula

posterior surface of the greater tubercle of the humerus

[C5,6]

rotation of arm at the glenohumeral joint

Medial lip of the Inferior Medial rotation and intertubercular sulcus subscapular nerve extension of the arm at the on the anterior [C5 to C7] glenohumeral joint surface of the humerus Subscapularis Medial two-thirds of Lesser tubercle of Upper and lower Rotator cuff muscle; medial subscapular fossa humerus subscapular nerves rotation of the arm at the [C5,C6(C7)] gleno-humeral joint Deltoid Inferior edge of the crest of Deltoid tuberosity of Axillary nerve Major abductor of arm the spine of the scapula, humerus [C5,C6] (abducts arm beyond initial lateral margin of the 15° done by supraspinatus); acromion, anterior border of clavicular fibers assist in lateral one-third of clavicle flexing the arm; posterior fibers assist in extending the arm Anterior Compartment of Upper Arm Biceps brachii Long head-supraglenoid Tuberosity of radius Musculocutaneous Powerful flexor of the tubercle of scapula; short nerve [C5,C6] forearm at the elbow joint head- apex of coracoid and supinator of the process forearm; accessory flexor of the arm at the glenohumeral joint Coracobrachiali Apex of coracoid process Linear roughening on Musculocutaneous Flexor of the arm at the s mid-shaft of humerus nerve [C5,C6,C7] glenohumeral joint; adducts on medial side arm Brachialis Anterior aspect of humerus Tuberosity of the Musculocutaneous Powerful flexor of the (medial and lateral surfaces) ulna nerve [C5,C6]; forearm at the elbow joint and adjacent intermuscular (small contribution septae by the radial nerve [C7] to lateral part of muscle) Posterior Compartment of the Upper Arm Long head of Infraglenoid tubercle on Common tendon of Radial nerve Extension of the forearm at triceps brachii scapula insertion with medial [C6,C7,C8] the elbow joint; accessory and lateral heads on adductor and extensor of the the olecranon process arm at the glenohumeral of ulna joint Triceps brachii Long head-infraglenoid Olecranon Radial nerve Extension of the forearm at (and anconeus) tubercle of scapula; medial [C6,C7,C8] the elbow joint. Long head head-posterior suface of can also extend and adduct humerus; lateral headthe arm at the shoulder joint posterior surface of humerus 18

Movements of the Arm

Movements of the Joints and muscles creating them Shoulder Joint: • Flexion:  Clavicular head of pectoralis major  Anterior fibres of deltoid  Coraco-brachialis  Biceps • Extension – Latissimus dorsi • Abduction:  Supraspinatus (first 30 degrees)  Central fibres of deltoid (after 30 degrees) • Adduction:  Pectoralis major  Latissimus dorsi • Internal rotation – subscapularis • External rotation – infraspinatus • Circumduction – a combination of all movements Muscles involved in preventing shoulder dislocation:  Rotator cuff muscles – depress the humeral head into the glenoid  Deltoid  Coraco-brachialis  Short and long heads of biceps The scapulo-thoracic joint: • Elevation – superior trapezius, levator scapulae, rhomboids • Depression – inferior trapezius, pectoralis minor, serratus anterior • Protraction – pectoralis minor, serratus anterior • Retraction – rhomboids, middle trapezius, latissimus dorsi • Rotation – elevation and depression of the glenoid fossa: • Elevation – superior trapezius, inferior trapezius, serratus anterior • Depression – pectoralis minor, latissimus dorsi, rhomboids and levator scapulae The Elbow Joint: • Flexion – biceps, brachialis, brachioradialis (pronator teres) • Extension – triceps (anconeus)

The Axilla • •

•

A gateway for nerves and vessels into the upper limb Shaped like a pyramid:  Base – skin, subcutaneous tissue and a facia extending from arm to chest st  Apex lies between the 1 rib, the clavicle and the superior border of the subscapularis muscle  Anterior wall – formed by pec major and minor  Posterior wall – formed by scapula and subscapularis superiorly and teres minor and latissimus dorsi inferiorly st th  Medial wall – formed by chest wall (1 to 4 ribs) and serratus anterior  Lateral wall – formed by humerus Contents:  Arteries – axillary and its branches  Veins – axillary and tributaries  Lymphatic vessels and lymph nodes – axillary lymph nodes particularly important  Nerves – brachial plexus

Vessels of the Region Subclavian Artery: arises from brachiocephalic artery (right side) or the aortic arch (left side). Runs in the root of the neck where it becomes the axillary. Axillary Artery: the subclavian artery becomes the axillary artery as it enters the axilla (as it comes over the margin of rib 1). This is split into 3 parts and numerous branches come off this: first part is proximal to the pec major second part is posterior to pec major third part is distal to pec major It supplies the walls of the axilla and associated regions. Brachial Artery: the axillary artery becomes the brachial artery as soon as it passes the teres major muscle. It is found in the anterior compartment on the medial side. It passes down the arm laterally and crosses anterior to the elbow joint. It gives off a brach that supplies the posterior compartment of the arm (the profunda brachii artery). The brachial artery gives off a number of other branches and divides at the elbow to form the radial and ulnar arteries. Axillary Vein: this deep vein is formed by two superficial veins, the basilic vein and the cephalic vein. The cephalic and basilic veins are the superficial veins of the forearm. The cephalic passes on the lateral aspect pf the arm and terminates by passing deep in the delto-pectoral triangle to join the axillary vein. The basilic vein passes on the medial side of the arm and passes deep halfway up to form the axillary vein along with the venae comitantes of the brachial artery The axillary vein receives many tributaries such as the brachial veins, and the venae comitantes of the brachial artery. The typical site for peripheral venous access is the cephalic vein. 23

At the first rib the axillary vein becomes the subclavian vein.

Nerves All the nerves that supply the shoulder and arm arise from the brachial plexus. All of which arise from the rami of C5-T1 spinal nerves. It consists of: 1. Long Thoracic Nerve – supplies serratus anterior: NB – if this is damaged in any way, then the serratus anterior muscle is unable to pull the scapula against and over the thoracic wall. This results in winging of the scapula if the patient pushes against something. Normal elevation of the arm is also no longer possible. 2. Suprascapular Nerve – supplies supraspinatus and infraspinatus 3. Lateral pectoral nerve – supplies pectoralis major 4. Thoraco-dorsal nerve – latissimus dorsi. 5. The axillary nerve – supplies teres minor and then the deltoid as well as an area of skin over the deltoid. 6. The musculo-cutaneous nerve (C567) is the nerve of the anterior compartment of the upper arm (coraco-brachialis, brachialis and biceps). It continues as the lateral cutaneous nerve of the forearm. It lies close to the subscapularis tendon anterior to the shoulder and can be damaged at the time of surgery to the front of the shoulder. It also supplies sensory innervation to the skin on the lateral surface of the forearm. 7. The ulnar nerve (C8T1) is one of the nerves that supplies the anterior compartment of the forearm but is mainly the nerve of the hand. It enters the arm with the median nerve and passes medial to the axillary artery. It lies posterior to the medial epicondyle of the elbow and can be damaged there. 8. The median nerve (C678T1) is one of the nerves that supply the anterior compartment of the forearm and hand. It enters the arm from the axilla at the inferior margin of the teres major muscle and passes vertically through the upper arm via the anterior compartment. At the level of the elbow it lies alongside the brachial artery and can be damaged there at the time of elbow fractures or dislocations. 9. The radial nerve (C5678T1) supplies the posterior compartment of the upper arm and forearm. It originates from the posterior cord of the brachial plexus and enters the arm by crossing the inferior margin of the teres major. It lies on the 24

humerus in the radial groove and can be damaged there. Just above the level of the elbow it divides into the superficial radial nerve (sensory) and the posterior interosseous nerve (motor).

Lymphatics  The hand is drained by the superficial lymphatics which run alongside the basilic (medially) and cephalic (laterally) veins  Elbow is drained by the cubital lymph nodes.  Delto-pectoral nodes run alongside the cephalic vein.  Deep lymphatics run alongside the deep veins. All of these lymph nodes in the arm drain toward the axillary nodes. These are very important as they also drain the breast (breast cancer). There are 5 groups of axillary nodes: - humeral (lateral) nodes - pectoral (anterior) nodes - subscapular (posterior) nodes - central nodes - apical nodes The nodes are important in breast cancer as are the site of lymph drainage from the breast as well.

Limbs 3 – Elbow, Forearm and Wrist Anil Chopra 1. Name the bones and joints of the upper limb from the elbow to the wrist 2. Demonstrate and explain the anatomical basis of elbow flexion and extension,, pronation and supination of the hand and the movements of the wrist 3. Demonstrate in a living subject the elbow the medial epicondyle, the olecranon process and the lateral epicondyle; the radius and ulna; the wrist joint 4. Demonstrate the courses of the major nerves through the region and also to point out where the nerves might be vulnerable to injury; 5. Demonstrate the courses of the brachial, radial and ulnar arteries from the axilla to the hand 6. Demonstrate the pulses associated with the brachial, radial and ulnar arteries 7. Demonstrate and name the main veins of the upper limb 8. Demonstrate clinical testing of the muscles, tendon, nerves and vessels in the forearm 9. Discuss a supracondylar fracture of the humerus and explain why this common injury can cause significant vascular and neurological complications and how may it be treated 10. Describe a Colles fracture, and explain why it is so common? Bones of the Region Distal end of Humerus: articulates with the radius and ulna. The distal end of the humerus has a number of articulations with the bones and ligaments it is attached to, including:  Condyle: consists of the capitulum (articulates with the radius) and the trochlea (articulates with the ulna).  Epicondyles: consist of the medial and lateral epicondyles. Both are palpable either side of the elbow. The ulnar nerve can be palpated on the posterior surface of the medial epicondyle.  Fossae: consist of the radial, coronoid and olecranon and are the sites into which projections slide as the forearm moves. The joint itself is in contact with 4 nerves that can be damaged during fracture or dislocation: - Axillary nerve – surgical neck of humerus - Radial nerve – radial groove - Ulnar nerve – posterior to medial epicondyle - Median nerve – anterior to distal humerus

Radius: at its proximal end, the radius articulates with the capitulum of the humerus and the radial notch at the proximal end of the ulna.  The radius rotates around the ulna  The radial tuberosity is a roughened surface on the medial end of the radius and attaches with the biceps tendon.  At its distal end, it has the ulnar notch (articulates with the ulna), the styloid process, the facets for its articulation with the scaphoid and lunate bones.  This is frequently fracture (Colles’ fracture) and is caused by falling onto outstretched hands. Ulna: the main function of the ulna is to stabilise the arm.  At its proximal end, the ulna has a large projection known as the olecranon (the bony part of the elbow), the trochlear notch (which articulates with the trochlea of the humerus), the radial notch (articulates with radius) tuberosity of the ulna (attaches to the brachialis) and the attachment of the anconeus on the posterior side.  At its distal end, it has an ulnar styloid process (on the medial aspect).  Its main movement is extension and flexion of the elbow.

Carpal Bones: consists 8 bones, split into a proximal and distal row: (Some lovers try positions that they can’t handle)  Proximal o Trapeziu o Scaphoid m o Lunate o Trapezoi o Triquetrum d o Capitate o Pisiform o Hamate  Distal

Joints of the Region Elbow Joint The elbow joint is a synovial hinge joint between the ulna and the humerus.  It involves 3 articulations sharing a common synovial cavity (covered in hyaline cartilage).  The main articular joint is between the trochlear notch of the ulna and the trochlea.  The distal humerus articulates with the ulna via the trochlea whilst the radius articulates with the humerus via the capitulum  The joint capsule is reinforced by fat pads which move out of the way as the elbow flexes and extends.  The anular ligament of the radius cuffs the head of the radius into the ulna, and the joint is held together using the ulnar and radial collateral ligaments.  The carrying angle is the angle between the axis of the humerus and the axis of the ulna and radius.  There is a large bursa over the olecranon at the back of the elbow – the olecranon bursa. This frequently becomes inflamed. Radio-Ulnar Joint  At the proximal end the head of the radius sits in the radial notch of the ulna and is able to rotate in supination and pronation. It is held in place by the anular ligament of the radius.  The radius and ulna are held together along their shafts by the interosseous membrane.  At the distal end, the ulnar notch of the radius is able to rotate around and over to the top of the head of the ulna in supination and pronation. Within the distal radio-ulnar joint is an articular disc called the triangular fibro-cartilage, which is commonly injured Supination: supinator & biceps Pronation: pronator quadratus & pronator teres Wrist Joint The bones that articulate with the distal ends of the radius and ulna are the scaphoid, lunate and triquetrum. Because the radial styloid process extends further than the ulnar styloid process, the wrist can be adducted more than it can be abducted. The ligaments of note here are the:  The ulnar collateral ligament  The radial collateral ligament  The palmar radio-carpal ligaments  The dorsal radio-carpel ligaments  The inter-carpel ligaments • The radio-carpel and inter-carpel ligaments are clinically important as are often injured • The wrist joint allows flexion and extension. The midcarpal and carpo-metacarpal also allow flexion and extension Intercarpal Joints Contribute to positioning of the hand.

Muscles of the Region

Muscle Origin Anterior Superficial Flexor carpi Humeral headulnaris medial epicondyle of humerus; ulnar head-olecranon and posterior border of ulna Palmaris longus

Medial epicondyle of humerus

Flexor carpi radialis

Medial epicondyle of humerus

Pronator teres

Humeral headmedial epicondyle and adjacent supraepicondylar ridge; ulnar headmedial side of coronoid process Humero-ulnar head-medial epicondyle of humerus and adjacent margin of coronoid process; radial headoblique line of radius

Flexor digitorum superficialis

Anterior Deep Flexor Anterior and digitorum medial surfaces of profundus ulna and anterior medial half of interosseous membrane

Flexor pollicis longus

Pronator quadratus

Anterior surface of radius and radial half of interosseous membrane Linear ridge on distal anterior surface of ulna

Posterior Superficial Brachioradialis Proximal part of lateral supraepicondylar ridge of humerus and adjacent inter-

Insertion

Innervation

Function

Pisiform bone, and then via pisohamate and pisometacarpal ligaments into the hamate and base of metacarpal V Palmar aponeurosis of hand

Ulnar nerve [C7,C8, T1]

Flexes and adducts the wrist joint

Median nerve [C7,C8]

Base of metacarpals II and III Roughening on lateral surface, mid-shaft, of radius

Median nerve [C6,C7]

Flexes wrist joint; because the palmar aponeurosis anchors skin of the hand, contraction of the muscle resists shearing forces when gripping Pronation

Median nerve [C6,C7]

Flexes and abducts the wrist

Four tendons, which attach to the palmar surfaces of the middle phalanges of the index, middle, ring, and little fingers

Median nerve [C8,T1]

Flexes proximal interphalangeal joints of the index, middle, ring, and little fingers; can also flex metacarpophalangeal joints of the same fingers and the wrist joint

Four tendons, which attach to the palmar surfaces of the distal phalanges of the index, middle, ring, and little fingers

Lateral half by median nerve (anterior interosseous nerve); medial half by ulnar nerve [C8,T1]

Palmar surface of base of distal phalanx of thumb

Median nerve (anterior interosseous nerve) [C7,C8] Median nerve (anterior interosseous nerve) [C7,C8]

Flexes distal interphalangeal joints of the index, middle, ring, and little fingers; can also flex metacarpophalangeal joints of the same fingers and the wrist joint Flexes interphalangeal joint of the thumb; can also flex metacarpophalangeal joint of the thumb Pronation

Distal anterior surface of radius

Lateral surface of distal end of radius

Radial nerve [C5,C6] before division into superficial

Accessory flexor of elbow joint when forearm is mid-pronated

Vessels of the Region Radial Artery: a branch of the brachial artery. That passes into along the forearm and into the hand in the dorsolateral part. It supplies mainly the arteries of the thumb and lateral index finger. In the forearm it has 3 main branches:  Radial recurrent artery – forms an anastomotic network of vessels around the elbow.  Palmar carpal branch – supplies carpal bones and joints  Superficial palmar branch – supplies the muscles at the base of the thumb. A radial pulse can be felt just proximal to the thumb on the anterior side of the wrist. Ulnar Artery: another branch of the brachial artery that passes down the medial side of the arm. It passes into the forearm to supply the medial three and a half fingers. It also has many branches in the forearm:  Ulnar recurrent artery: split into anterior and posterior to join the anastomotic network of vessels around the elbow.  Common interosseous artery: which divides into o Anterior interosseous artery: passes anteriorly along the interosseous membrane to supply the deep muscles of the forearm. o Posterior interosseous artery: passes dorsally to supply the posterior compartment of the forearm.  Carpal arteries: supply the wrist. An ulnar pulse can be felt on medial side of the forearm just proximal to the hand. Generally veins surround the arteries and drain into the brachial veins of the arm in the cubital fossa. Nerves of the Region Median Nerve: innervates the muscles in the anterior compartment of the forearm except the flexor carpi ulnaris (FCU) and index and middle fingers of the flexor digitorum profundus (FDP). It passes distally down the forearm and through the carpal tunnel. It has two major branches:  Anterior interosseous nerve: innervates the muscles in the deep layer of the forearm.  Palmar branch: innervates skin over the base and central palm. Ulnar Nerve: mainly supplies the hand although in the forearm it supplies the flexor carpi ulnaris (FCU) and ring and little fingers of the flexor digitorum profundus (FDP). It passes into hand superficial to the flexor retinaculum, not through the carpal tunnel. It also has 3 major branches:

 Muscular branches to the FCU and half of FDP.  Palmar branch to supply the skin on the medial side of the palm.  Dorsal branch to supply skin on the posterior side of the hand and the skin of one and a half digits. Radial Nerve: this bifurcates into a 2 branches on the lateral part of the cubital fossa:  Superficial branch is sensory and supplies the dorsolateral surface of the hand.  Deep branch is motor and supplies muscles in the posterior part of the forearm.

Limbs 4 – Hand Anil Chopra 1. 2. 3. 4. 5.

Name the bones and joints of the wrist and hand Name and demonstrate the movements of the wrist and hand Distinguish between the power and precision grips Outline the main neuromuscular mechanisms underlying each type of grip Summarise in simple terms the overall pattern of motor and sensory segmental nerve distribution to the limb 6. Explain (in principle only) the role of the brachial plexus 7. Explain the main motor and sensory deficits associated with carpal tunnel syndrome, ulnar nerve injury near the elbow, radial nerve injury in the spiral groove, injury to the lower segments of the brachial plexus 8. Outline the functional deficits caused by the common injuries of the flexor and extensor tendons 9. Outline the mallet finger deformity 10. Identify and summarise the functions of the carpal bones 11. Describe how fractures of the scaphoid occur and explain why such injuries are important 12. Discuss the clinical term, trigger finger 13. Describe gamekeeper’s thumb (skier’s thumb) and its anatomical basis. Bones of the Region The Carpel Bones: • Proximal row (lateral to medial)=  Scaphoid – forms the wrist joint  Lunate – forms the wrist joint  Triquetrum – forms the wrist joint  Pisiform – a sesimoid bone (develops in the tendon when it rubs forming a synovial joint (also seen in patella) is formed from FCU (flexor carpi ulnaris) • Distal row (lateral to medial) =  Trapezium – supports the thumb by forming a saddle joint with it  Trapezoid – supports the index finger  Capitate – supports the middle finger. Acts like a keystone in supporting the carpus  Hamate – supports the ring and little finger • The radius articulates with the scaphoid, lunate and triquetrum to form the wrist joint • The ulna does not articulate with the carpus except via the triangular fibrocartilage which extends from the distal radius to ulna • The scaphoid has a clinically important blood supply – blood vessels tend to pass from distal to proximal but can be interrupted by a fracture of the waist of the bone causing the proximal end to undergo avascular necrosis Metacarpals: 5 metacarpals, (the thumb is number I) consisting of a base, shaft and head.

Phalanges: each finger has 3 (proximal, middle and distal) the thumb has 2 (proximal and distal). Joints of the Region The distal radio-ulna joint: • A pivot joint that allows the radius to move around the ulna in rotation • Within the joint is an articular disc = triangular fibro-cartilgae which is commonly injured, the disc also allows the ulna to indirectly articular with the carpal bones The wrist joint: • A synovial joint between the distal radius and its associated triangular fibrocartilage and the proximal row of the carpal bones (scaphoid, lunate and triquetrum, but not pisiform) • Ligaments supporting the joint include:  The ulnar collateral ligament  The radial collateral ligament  The palmar radio-carpal ligaments  The dorsal radio-carpel ligaments  The inter-carpel ligaments • The radio-carpel and inter-carpel ligaments are clinically important as are often injured • The wrist joint allows flexion and extension. The midcarpal and carpo-metacarpal also allow flexion and extension • Radial and ulna deviation also occurs at the wrist joint The intercarpal joints: • Joints between the proximal row of carpal bones • Joints between the distal row of carpal bones • Joints between the proximal and distal row of carpal bones – the midcarpal joint • Main movements occurring at the carpal joints is gliding, augmenting the movement occurring at the wrist joint, especially flexion and radial deviation of the wrist Carpometacarpal joints • There are 5 joints between the carpal and metacarpal bones. The saddle joint between metacarpal I and the trapezium (the CMC of the thumb) is much more mobile than those of the fingers and often becomes arthritic. • The other CMC’s are between trapezoid, capitate and hamate with the metacarpals of the digits. The CMC’s of the middle finger are very rigid, that of ring finger less rigid and that of the little finger very mobile • There are also intermetacarpal joints (IMC) between the metacarpals at their bases Metacarpopharyngeal Joints • Metacarpophalangeal joints (MCP’s) are condylar synovial joints between the metacarpal heads and proximal phalanges • They allow for the following movements:  Flexion and extension  Abduction and adduction • The interphalangeal joints (IP’s) are hinge synovial joints which allow for flexion and extension

There is a proximal IP and distal IP in each digit – the thumb only has one IP • The collateral radial and collateral ulna ligaments hold the IP’s and MCP’s together • The ulnar collateral ligament in the thumb is particular important as it is often damaged skiing • The volar plate is an important structure on the anterior surface of the proximal interphalangeal plate. It is a dense condensation of fibrous tissue formed by the collateral ligaments at the front of the proximal IP joint •

The Carpal Tunnel The carpal tunnel is formed anteriorly at the wrist by the deep arch of carpal bones. Contents: • Median nerve • 4 heads of tendons of flexor digitorum profundus • 4 heads of the tendons of flexor digitorum superficialis • tendon of flexor pollicis flongus Carpal Tunnel Syndrome: the entrapment syndrome caused by pressure on the median nerve. Can be caused by swelling of tendons and formation of cysts in the carpal joints (e.g. rheumatoid arthritis). Symptoms include “pins-and-needles” in the muscles in the median nerve region, weakness, loss of muscle bulk of the thenar muscles. The fascia of the palm:  Anatomically continuous with the fascia of the forearm  Palmar fascia lies in the palm – condensations (speciliasations) form the palmer apponeurosis and the digital fibrous sheaths  The palmer apponeurosis  Well defined and overlies the long flexor tendons.  The proximal end is continuous with the flexor retinaculum and the palmaris longus tendon.  The distal end forms 4 bands which is continuous with the fibrous digital sheaths of each finger  The fibrous digital sheaths:  Are tubes which contain flexor tendons and their sheaths  The space between the palmar apponeurosis and the bones of the hands is separated into compartments by extensions of the fascia called septa  A medial septum (to the little finger metacarpal) and a lateral septum (middle finger metacarpal) divides the space into the hypothenar compartment, central compartment and thenar compartment (thenar closet to thumb, hypothenar closest to little finger)  Beneath the thenar compartment is the 4th compartment = adductor compartment which contains adductor pollicis

Intrinsic Muscles of the Hand

Thenar muscles: these consist of the  abductor pollicis brevis  flexor pollicis brevis  opponens pollicis These are all innervated by the median nerve and are responsible for opposition of the thumb. Hypothenar muscles: these consist of  opponens digiti minimi  abductor digiti minimi  flexor digiti minimi. They are innervated by the deep branch of the ulnar nerve. Dorsal interossei: originate on the dorsal sides of the metacarpals and insert in the proximal phalanges. They are responsible for abduction of the fingers (away from the middle) and are innervated by the deep branch of the ulnar nerve.

Palmar interossei: these originate from the palmar metacarpals and insert in the phalanges. They are responsible for adduction of the fingers (toward the middle) and are innervated by the deep branch of the ulnar nerve. Adductor pollicis: responsible for the adduction of the thumb and innervated by the deep branch of the ulnar nerve. Lumbricals: these cause the flexion of the metacarpophalangeal joints when the interphalangeal joints are extended (pointing). They are innervated by the deep branch of the ulnar nerve.

Types of Grip:  Power Grip (e.g. holding a rod)  long flexors of the fingers and thumb  intrinsic muscles of the palm  extensors of the wrist joint  Precision Grip (e.g. buttoning a shirt)  the wrist and fingers are held rigidly by the long flexors and extensors  the intrinsic muscles of the hand carry out the fine movements needed. TENDINOUS ANATOMY OF THE REGION: Anterior tendinous anatomy of the hand: » The fibrous digital sheath is a condenstation/specialisation of the palmar fascia » These sheaths extend from the level of the metacarpal head to the base of the distal phalanx in each digit » Together with the underlying bone form the osseo-fibrous tunnels through which the long flexor tendons and associated synovial sheaths run » Parts of the fibrous digital sheath forms condensations = pulleys which allow for more functional use » These are called the annular and cruciform pulleys » Just after the wrist joint the tendons of FDP (flexor digitorum profundus) and FDS (flexor digitorum superficialis) pass deep to the flexor retinaculum and enter a common synovial sheath » Tendons then pass to the respective digit via a digital synovial sheath which is contained within the fibrous digital sheath » At the base of the proximal phalanx FDS splits around FDP – FDS attaches to the anterior surface of the middle phalanx, FDP to the distal phalanx » Flexor pollicis longus (the long thumb flexor) has its own synovial sheath at the flexor retinaculum – runs to the distal phalanx of thumb Posterior tendinous anatomy: » All the extensor tendons are held to the back of the wrist by the extensor retinaculum » Synovial tendon sheaths that surround the tendons allow for free movement » On the back of the hand the long extensor tendons are joined by bands called inter-tendinous bands which prevent the free movement of one tendon independently to the others » At the level of the metacarpals the long extensor tendons flatten to form extensor expansions which form a hood on the back of the digit » The lumbricals and interossei attach to the extensor expansions » Extensor digitorum extends to the MCP and IP joints. It also plays a part in extension of the wrist

Vessels of the Region Ulnar artery: passes in the anterior compartment of the forearm along the ulna and enter the hand on the medial side of the wrist (not through the carpal tunnel). The vessel lies between the palmaris brevis and the flexor retinaculum and is lateral to the ulnar nerve and the pisiform bone. Distally, the ulnar artery is medial to the hook of the hamate bone and then swings laterally across the palm, forming the superficial palmar arch, which is superficial to the long flexor tendons of the digits and just deep to the palmar aponeurosis. On the lateral side of the palm, the arch communicates with a palmar branch of the radial artery. Branches from the superficial palmar arch include: • a palmar digital artery to the medial side of the little finger; • three large, common palmar digital arteries, which ultimately provide the principal blood supply to the lateral side of the little finger, both sides of the ring and middle fingers, and the medial side of the index finger -they are joined by palmar metacarpal arteries from the deep palmar arch before bifurcating into the proper palmar digital arteries, which enter the fingers Radial Artery: curves around the lateral side of the wrist and passes over the floor of the anatomical snuffbox and straight into the back of hand (not through the carpal tunnel). It passes between the two heads of the first dorsal interosseous muscle and then between the two heads of the adductor pollicis to access the deep plane of the palm and form the deep palmar arch. It splits to from the deep and superficial palmar arches before it reaches the thumb. It supplies the radial half of the index finger and the thumb.

Cephalic Vein: originates form the lateral side of the dorsal venous network and passes over the anatomical snuffbox into the forearm. Basilic vein: originates on the medial side of the dorsal venous network and passes into the Dorsomedial aspect of the forearm. Nerves of the Region Ulnar Nerve: (C8 T1) the ulnar nerve enters the hand lateral to the Pisiform and dorsomedially to the ulnar artery. It divides into deep and superficial branches. The superficial branch supplies the Palmaris brevis, and is sensory for the skin of the little and half of the ring finger. The deep branch supplies all the intrinsic hand muscles except for the thenar muscles thus making it the main nerve for fine movements. Injury to the ulnar nerve causes clawing of the hand. This is because of the inhibition of intrinsic muscles of the hand. Median nerve: (C678 T1) the median nerve enters the hand by passing through the carpal tunnel and dividing into a recurrent branch and digital branches. The digital branches are sensory for the thumb, index, middle and half of the ring finger. The recurrent branch provides motor innervation for the thenar muscles and the first and second lumbricals. NB: Median nerve also supplies the anterior compartment of the forearm except the flexi carpi ulnaris and the ulnar portion of ht flexor digitorum profundus. Radial Nerve: (C5678 T1) only the superficial branch of the radial nerve enters the hand and it does so by passing over the anatomical snuffbox. Its function is only to innervate skin on the dorsal aspect of the hand. Injury to the radial nerve results in wrist drop. NB: Posterior inersseous nerve is a direct continuation of the radial nerve and passes between the heads of supinator to supply the extensor compartment of the forearm.

Limbs 5 – Brachial Plexus Anil Chopra 1. Summarise in simple terms the overall patterns of motor and sensory segmental nerve distribution to the limb 2. Explain (in outline only) the role of the brachial plexus 3. Demonstrate where the axillary, radial, median and ulnar nerves nerves are vulnerable to injury 4. Explain the main motor and sensory deficits associated with carpal tunnel syndrome, ulnar nerve injury near the elbow, radial nerve injury in the spiral groove, axillary nerve injury and injury to the roots of the brachial plexus Brachial Plexus Arise from cervical spinal cords C5 – T1 in the neck. Patients however can have prefixed or post-fixed brachial plexi (e.g. C4-C8 or C6-T2). Reasons for Brachial Plexus: - Limbs are so important that we can’t have one muscle supplied by one segement in case of leision. The same applies for sensory terms. - Developmental: muscles more distal are innervated by spinal segments lower down the spinal cord. - Nerves grow out in order down the spinal cord, but not all of the muscle can be supplied by one nerve, when one nerve finishes, the next nerve “mops up” the rest of the muscle. C5 & 6 join together to form upper trunk of brachial plexus. C7 is on its own and forms the middle trunk of brachial plexus C8 & T1 join together to form the upper trunk of the brachial plexus. • C3-C7 supply shoulder girdle muscles • C5-C6 supply shoulder joint muscles and elbow flexors • C7-C8 supply elbow joint extensors • C6-C8 supply wrist and coarse hand muscles • C8-T1 supply small muscles of hand (fine movements) Injuries to the Axillary Nerve Posterior Cord: splits into axillary nerve (motor to teres minor and deltoid). Most commonly injured through dislocations of the shoulder as it wraps around the proximal head of the humerus. Will not be able to abduct the shoulder and causes wasting of the deltoid muscle. Can be tested by testing sense in the “badge area”. Other is radial nerve. Particularly damaged through fractures of the humerus. Results in “wrist drop”, loss of power grip. Musculocutaneous nerve: use left hand when unscrewing. Injury caused by surgery. Supplies biceps, brachialis and sensory innervation to skin. Ulnar nerve: Part of the medial cord, it is most susceptible to fractures when it passes posterior to the epicondyle of the humerus at the elbow. Injury here results in clawing

of the hand, but not as much as if it is injured at the wrist because the flexors to the median 2 digits are lost as well. Median Nerve: loss of fine motor skills of the hand due to loss of flexion of the fingers – no innervation to the anterior forearm muscles.

U M Lat Post

Med Trunks Cords Lower Root Injuries Pathways affected: Roots C8 and T1 form the lower trunk of the plexus The anterior division of this trunk forms the ulnar nerve and the cutaneous nerve of the arm and forearm and contributes to the median nerve The posterior division contributes to the posterior cord, through which it reaches the radial nerve Segmental innervation: Motor: Effects are on the most distal parts – especially the hand Sensory: the dermatomes of C8 and T1 cover the medial aspect of the limb between axilla and wrist. Sensory effects: Sensation is altered or lost on the medial aspect of the arm and forearm and possibly the little finger, but is retained in the rest of the hand (mainly C7) Motor effects: Most important is the total loss of intrinsic hand muscles and therefore loss of precision movements. The long extensors and flexors continue but, in the absence of functional fine control from the intrinsic muscles, they tend to hold the hand in a rather immobile, clawed position

Limbs 6 - Hip, Buttock and Thigh Anil Chopra 1. Identify the bones and joints of the lumbo-sacral region, hip joint and femur 2. Find the following landmarks in the living subject: the mid-inguinal point, the anterior superior iliac spine, the symphysis pubis and the pubic tubercle, the greater trochanter, the medial and lateral femoral epicondyles 3. Demonstrate the following prime movers and muscle groups and the main movements associated with them; a. gluteus maximus b. hip abductors c. ilio-psoas d. hip adductors e. the hamstrings f. quadriceps femoris g. the sartorius

2. Assign muscle groups to the following nerves: the gluteal nerve, the femoral nerve, the obturaor nerve, the sciatic nerve in the thigh 3. Describe a hamstring injury in sportspersons 4. Trace the routes of the femoral artery and the profunda femoris artery 5. Demonstrate the femoral pulse and explain its significance 6. Discuss femoral neck fractures. 7. Explain the difference between intracapsular fractures and extracaspsular fractures of the femoral neck and their clinical importance 8. Describe the Trendelenberg test 9. Briefly describe the principles behind total hip replacement. Bones of the Region Pelvis Ilium: this forms the fan shaped part of the body pelvis. The top of it is the iliac crest ending anteriorly at the ACIS – anterior superior iliac spine (at L5) and posteriorly at the posterosuperior iliac spine. Ischial Tuberosity: associated with the attachments for the hamstring muscles. Pokes out postero-inferiorly from the acetabulum. Acetabulum: the large cup-shaped space associated with articulation with the head of the femur. Pubic Bone: the external surface of the ischiopubic ramus anterior to the ischial tuberosity. It provides attachments for the adductor muscles in the medial compartment of the thigh. NB:All the bones of the pelvis are fused. Sacrum: See spinal anatomy. It articulates with the hip-bone at the sacro-iliac joint. Femur: consists of the head, neck and two trochanters proximally. The proximal head of the femur inserts into the acetabulum. The neck of the femur is a cylindrical strut that connects the head to the shaft. The upper part of the shaft bears the lesser trochanter (attachment for psoas major and iliacus) and the greater trochanter (attachment for the obturator externus, gluteus medius and minimus) which are jointed by the intertrochanteric line and intertrochanteric crest posteriorly. There is a line on the shaft of the femur running posteriorly called the linea aspera.

Fractures of the neck of the femur can cause disruptions to a number of hip vessels and result in necrosis of the femoral head. Joints of the Region Sacro-iliac joint: articulation is fixed. Hip joint: a synovial articulation between the head of the femur and the acetabulum. It is a ball and socket joint and is designed for stability and weightbearing at the expense of flexibility. This is achieved by the acetabulum wrapping almost entirely round the hemisphere of the femoral head. The femoral head is held in place by a number of ligaments o Iliofemoral ligament: anterior to the hip joint o Pubofemoral ligament: anteroinferior to the hip joint o Ischiofemoral ligament: posterior aspect of hip joint - Around the rim of the acetabulum is a rim of tissue called the acetabular labrum - Within the acetabulum is also the transverse acetabular ligament - The capsule of the joint extends down the femur – extends further anteriorly than posteriorly - The capsule contains the important blood supply for the head - Fractures are either intracapsular or extracapsular - Important ligaments at the hip joint: o Ilio-femoral ligament o Pubo-femoral ligament o Ischio-femoral ligament o Ligament of the head of the femur - The blood supply of the joint is derived from the medial and lateral circumflex arteries mainly - Insignificant blood supply for the adult, but significant in the child is provided by the artery of the head of the femur - Circumflex vessels easily damaged in intracapsular fractures of proximal femur leading to avascular necrosis

Foramina of the Hip and Lower Limb

The gluteal region: » Contains important ligaments which connect the bones of the region and provides passageway for nerves and vessels » The greater sciatic notch and the lesser sciatic notch are converted into the greater sciatic foramen and lesser sciatic foramen by the sacrotuberous ligament and sacro-spinous ligament » Greater sciatic foramen – structures passing from pelvis to lower limb (including sciatic nerve) » Lesser sciatic foramen – structures passing from pelvis to perineum The femoral triangle: Borders:  Superior – inguinal ligament  Medial – adductor longus  Lateral - sartorius It contains the femoral nerve, femoral artery and femoral vein (lateral to medial). The femoral sheath encloses the artery and vein but not the nerve. Medially the sheath forms the femoral canal.

The adductor canal: • Extends on the medial aspect of the thigh from the apex of the femoral triangle • Transmits the superficial femoral artery and vein and the saphenous nerve • Formed by:  Anteriorly – vastus medialis  Posteriorly – adductor longus and mangus  Medially – sartorius

Muscles of the Region Gluteal – extensors and abductors of the hip Gluteus minimus

External surface of ilium between inferior and anterior gluteal lines

Linear facet on the anterolateral aspect of the greater trochanter

Superior gluteal nerve (L4,L5,S1)

Gluteus medius

External surface of ilium between anterior and posterior gluteal lines

Elongate facet on the lateral surface of the greater trochanter

Superior gluteal nerve (L4,L5,S1)

Gluteus maximus

Fascia covering gluteus medius, external surface of ilium behind posterior gluteal line, fascia of erector spinae, dorsal surface of lower sacrum, lateral margin of coccyx, external surface of sacrotuberous ligament

Posterior aspect of iliotibial tract of fascia lata and gluteal tuberosity of proximal femur

Inferior gluteal nerve (L5,S1,S2)

Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh Abducts femur at hip joint; holds pelvis secure over stance leg and prevents pelvic drop on the opposite swing side during walking; medially rotates thigh Powerful extensor of flexed femur at hip joint; lateral stabilizer of hip joint and knee joint; laterally rotates and abducts thigh

Short External Rotators of the Hip Tensor fasciae latae

Lateral aspect of crest of ilium between anterior superior iliac spine and tubercle of the crest Anterior surface of sacrum between anterior sacral foramina

Iliotibial tract of fascia lata

Superior gluteal nerve (L4,L5,S1)

Stabilizes the knee in extension

Medial side of superior border of greater trochanter of femur

Branches from (S1,S2)

Medial side of greater trochanter of femur

Gemellus superior

Anterolateral wall of true pelvis; deep surface of obturator membrane and surrounding bone External surface of ischial spine

Nerve to obturator internus (L5,S1) Nerve to obturator internus (L5,S1)

Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint Laterally rotates the extended femur at hip joint; abduction of flexed femur at hip joint

Gemellus inferior

Upper aspect of ischial tuberosity

Nerve to quadratus femoris (L5,S1)

Laterally rotates the extended femur at hip joint; abducts flexed femur at hip joint

Quadratus femoris

Lateral aspect of the ischium just anterior to the ischial tuberosity

Nerve to quadratus femoris (L5,S1)

Laterally rotates femur at hip joint

Piriformis

Obturator internus

Along length of superior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon Along length of inferior surface of the obturator internus tendon and into the medial side of greater trochanter of femur with obturator internus tendon Quadrate tubercle on the intertrochanteric crest of the proximal femur

Anterior Thigh – Hip flexors and Knee extensors Psoas major

Posterior abdominal wall (lumbar transverse processes, intervertebral discs, and adjacent bodies from TXII to LV and tendinous arches between these points)

Lesser trochanter of femur

Anterior rami L1,L2,L3

Flexes the thigh at the hip joint

Iliacus

Posterior abdominal wall (iliac fossa)

Lesser trochanter of femur

Femoral nerve [L2,L3]

Flexes the thigh at the hip joint

Vastus medialis

Femur-medial part of intertrochanteric line, pectineal line, medial lip of the linea aspera, medial supracondylar line

Quadriceps femoris tendon and medial border of patella

Femoral nerve [L2,L3,L4]

Extends the leg at the knee joint

Vastus intermedius

Femur-upper two-thirds of anterior and lateral surfaces

Quadriceps femoris tendon and lateral margin of patella

Femoral nerve [L2,L3,L4]

Extends the leg at the knee joint

Vastus lateralis

Femur-lateral part of intertrochanteric line, margin of greater trochanter, lateral margin of gluteal tuberosity, lateral lip of the linea aspera

Quadriceps femoris tendon

Femoral nerve [L2,L3,L4]

Extends the leg at the knee joint

Rectus femoris

Straight head originates from the anterior inferior iliac spine; reflected head originates from the ilium just superior to the acetabulum

Quadriceps femoris tendon

Femoral nerve [L2,L3,L4]

Flexes the thigh at the hip joint and extends the leg at the knee joint

Sartorius

Anterior superior iliac spine

Anterior surface of tibia just inferomedial to tibial tuberosity

Femoral nerve [L2,L3]

Flexes the thigh at the hip joint and flexes the leg at the knee joint

Medial Compartment – hip adductors Gracilis

A line on the external surfaces of the body of the pubis, the inferior pubic ramus, and the ramus of the ischium

Medial surface of proximal shaft of the tibia

Obturator nerve [L2,L3]

Adducts thigh at hip joint and flexes leg at knee joint

Pectineus

Pectineal line and adjacent bone of pelvis

Oblique line extending from base of lesser trochanter to linea aspera on posterior surface of proximal femur

Femoral nerve [L2,L3]

Adducts and flexes thigh at hip joint

Adductor longus

External surface of body of pubis (triangular depression inferior to pubic crest and lateral to pubic symphysis)

Linea aspera on middle onethird of shaft of femur

Obturator nerve (anterior division) [L2,L3,L4]

Adducts and medially rotates thigh at hip joint

Adductor brevis

External surface of body of pubis and inferior pubic ramus

Posterior surface of proximal femur and upper one-third of linea aspera

Obturator nerve[L2,L3]

Adducts thigh at hip joint

Adductor magnus

Adductor part-ischiopubic ramus

Posterior surface of proximal femur, linea aspera, medial supracondylar line

Obturator nerve [L2,L3,L4]

Adducts and medially rotates thigh at hip joint

Hamstring part-ischial tuberosity

Adductor tubercle and supracondylar line

Sciatic nerve (tibial division) [L2,L3,L4]

External surface of obturator membrane and adjacent bone

Trochanteric fossa

Obturator nerve (posterior division) [L3,L4]

Obturator externus

Posterior Compartment – hip extensors and knee flexors Biceps femoris

Long head-inferomedial part of the upper area of the ischial tuberosity; short head-lateral lip of linea aspera

Head of fibula

Sciatic nerve [L5 to S2]

Flexes leg at knee joint; extends and laterally rotates thigh at hip joint and laterally rotates leg at knee joint

Semitendinosus

Inferomedial part of the upper area of the ischial tuberosity

Medial surface of proximal tibia

Sciatic nerve [L5 to S2]

Flexes leg at knee joint and extends thigh at hip joint; medially rotates the thigh at the hip joint and leg at the knee joint

Semimembranosu s

Superolateral impression on the ischial tuberosity

Groove and adjacent bone on medial and posterior surface of medial tibial condyle

Sciatic nerve [L5,S1,S2]

Flexes leg at knee joint and extends thigh at hip joint; medially rotates thigh at the hip joint and leg at the knee joint

Vessels of the Region External Iliac Artery: passes from the pelvis beneath the inguinal ligament into the femoral triangle to become the femoral artery. Femoral Artery: this is the major artery that supplies the lower limb. It is a continuation of the external iliac artery. It gives rise to the profunda femoris artery, which itself gives rise to the circumflex vessels which supply the muscles of the thigh. » Palpable at the mid-inguinal point (half-way between the anterior superior iliac spine and pubic symphysis) » It is lateral to the femoral vein and medial to femoral nerve At the knee it becomes the popliteal artery Gluteal Arteries: there are 2 main gluteal arteries, the superior and inferior. They originate in the pelvic cavity and are branches of the internal iliac artery. They supply the gluteal regions. Obturator Artery: another branch of the internal iliac artery, it supplies the medial compartment of the thigh.

Femoral Vein: this is the main deep vein draining the lower limb. The deep veins of the thigh drain into the popliteal vein which becomes the femoral vein. It becomes the external iliac vein when it crosses the inguinal ligament, which itself joins the internal iliac vein to form the common iliac vein. Saphenous Veins: these are the main superficial veins of the lower limb. All the superficial veins drain into these including the venae comitantes of the profunda femoris vein. They join the femoral vein at the saphenofemoral junction. There are 2, the great (long) saphenous vein and the small saphenous vein. The LSV pierces the fascia of the thigh to join the deep system at the femoral triangle. There is an important valve at the sapheno-femoral junction which prevent blood passing from deep to superficial – incompetence causes varicose veins.

Varicose veins - a condition caused by incompetence of valves in the veins. This causes blood to pile up in the lower veins. It can increase the risk of deep vein thrombosis, is unsightly, causes an increase in pressure and hence can damage capillaries thus producing a brown pigmentation of the skin and venous eczema. Also increases risk of skin ulcers. Lymphatics of the region » Lymph drainage follows the superficial and deep systems » Superficial system runs with long and short saphenous veins and has superficial inguinal lymph nodes in the groin » These drain into the inguinal lymph nodes and external iliac lymph nodes » The deep system drains alongside the deep veins to the deep inguinal lymph nodes which drain to the external iliac lymph nodes

Nerves of the Region Motor segmental supply: » Hip flexors – L23 » Hip extensors – L45 » Knee extensors – L34 » Knee flexors – L5 S1 The nerves of the lower limb all originate from the lumbosacral plexus. There are a number of nerves that emerge: Femoral Nerve: leaves the abdomen by passing under the inguinal ligament and into the femoral triangle. It innervates all the muscles on the anterior compartment of the thigh as well as the skin of the anterior aspect of the thigh, the medial side of the leg and the medial side of the foot. It arises from spinal levels L3 and L4. Sciatic Nerve: the largest nerve in the body, and carries contributions from L4 – S3. It enters the leg through the greater sciatic foramen and passes through the gluteal region. Passes through buttock and divides at an inconsistent level on the posterior aspect of the thigh into the tibial nerve and common peroneal nerve. It innervates the posterior compartment of the thigh, as well as all the muscles of the leg and foot, and the skin on the lateral side of the leg and the lateral sole of the foot. If the buttock is divided into quadrants the nerve lies in the inferior and medial – therefore injections always given in the superior and lateral compartments. Obturator Nerve: this also originates from L2 to L4, but descends along the posterior abdominal wall and enters the thigh through the obturator canal. It innervates the medial compartment of the thigh and the skin on the medial and upper thigh. Gluteal Nerves: there are 2 nerves that supply the gluteal region, the superior gluteal nerve supplies the gluteus minimus and medius, and the inferior gluteal nerve supplies the gluteus maximus.

Trendelenberg Test • Important test of hip abductor function = Trendelenberg Test  Stand on one leg  The contralateral pelvis should rise as a result of the abductor muscles (gluteus medius and minimus)  If dips = positive test. Patients with a positive test waddle when they walk True leg length = the measurement between the medial malleolus of the ankle and the anterior superior iliac spine ( a fixed bony part of the pelvis) • Apparent leg length = measurement between the medial malleolus and the xiphisternum •

Hip Fractures There are four types of “hip fracture”The differences between them are important because each is treated differently. • Femoral head fracture denotes a fracture involving the femoral head. This is usually the result of high energy trauma and a dislocation of the hip joint often accompanies this fracture. • Femoral neck fracture (sometimes Neck of Femur (NOF), subcapital, or intracapsular fracture) denotes a fracture adjacent to the femoral head in the neck between the head and the greater trochanter. These fractures have a propensity to damage the blood supply to the femoral head, potentially causing avascular necrosis. • Intertrochanteric fracture denotes a break in which the fracture line is between the greater and lesser trochanter on the intertrochanteric line. It is the most common type of 'hip fracture' and prognosis for bony healing is generally good if the patient is otherwise healthy. • Subtrochanteric fracture actually involves the shaft of the femur immediately below the lesser trochanter and may extend down the shaft of the femur.

Limbs 7 – Knee, Popliteal Fossa, Leg and Foot Anil Chopra 1. Identify the bones and joints of the entire lower limb 2. Find the following landmarks in the living subject; a. the medial and lateral femoral epicondyles b. the patella and the patellar ligament c. the head of the fibula d. the medial and lateral malleoli e. the navicular tuberosity f. the base of the fifth metatarsal g. the head of the first metatarsal 3. Demonstrate the following prime movers and muscle groups and the main movements associated with them; a. the gastrocnemius-soleus (the superficial flexor compartment of the leg) b. the deep flexor compartment of the leg c. the peroneal compartment of the leg d. the extensor compartment of the leg 4. Assign muscle groups to the following nerves; a. the sciatic nerve in the thigh b. the tibial nerve c. the common peroneal nerve 5. Trace the routes of the femoral artery, the profunda femoris artery, the anterior tibial artery and the posterior tibial artery 6. Demonstrate the femoral pulse, the popliteal pulse, the posterior tibial pulse and the dorsalis pedis artery and explain their significance 7. Briefly explain the operation of total knee replacement and potential damage during the operation 8. Describe arthroscopy of the knee joint 9. Discuss the common injury of anterior cruciate ligament rupture. 10. Discuss Achilles Tendon Ruptures and their anatomical bases 11. Discuss the clinical entity of compartment syndrome and explain its anatomical basis. Bones of the Region Distal Femur: the course of the femur is oblique, resulting in the knee being closer to the midline under the body’s centre of gravity. The shaft of the femur is triangular and has smooth surfaces. The distal end of the femur has 2 epicondyles, lateral and medial in between which is the intercondylar fossa. In here the medial epicondyle attaches to the posterior cruciate ligament and the lateral epicondyle to the anterior cruciate ligament.

Tibia: tibia is medial and the larger of the 2 bones that make up the leg and the only one that articulates with the femur. At its proximal end it flattens into a transverse plane used for weight bearing. It has 2 condyles, lateral and medial – thick horizontal parts of the bone attached to the top of the shaft (the parts in between them known as the intercondylar eminence). There are 6 facets for the attachment of ligaments and menisci (moon shaped cartilaginous tissues): - medial meniscus – attaches both anteriorly and posterior - anterior cruciate ligament - lateral meniscus – attaches both anteriorly and posteriorly - posterior cruciate ligament The distal end of the tibia is shaped like a rectangular box with a bony protuberance on the medial side – the medial malleolus, the inferior of which articulates with the talus (a tarsal bone). On its lateral side it contains a deep triangular notch (the fibular notch) to which the distal head of the fibula is anchored by a thickened part of the interosseous membrane.

Fibula: the most lateral bone of the leg and is not involved at the knee joint. Its head is an expansion at its proximal end and contains attachments for the biceps femoris and the collateral ligament. It has a facet for articulation with the lateral condyle of the tibia and a process sticking out of the top called the styloid process. The fibula is narrower than the tibia as it is not involved in weight bearing. The distal end of the tibia expands to form the lateral malleolus. It articulates with the lateral surface of the talus hence forming the lateral part of the ankle.

Patella: also known as the “knee cap”, the patella is a sesamoid bone (formed within a tendon) and is an attachment for the quadriceps tendon and the patellar ligament. It is triangular in shape and sits anterior to the distal end of the femur.

The Foot Tarsal Bones: the tarsal bones are split into 2 main groups, the proximal group consists  Talus – a snail shaped bone that articulates with the tibia and fibula. It has a rounded head, which projects forward onto a short broad neck. The head is domed anteriorly – the talar dome, which articulates with navicular bone. At its posterior end, it has a groove for the attachment of the flexor hallucis longus.  Calcaneus – an irregular shaped bone that sits underneath the talus and forms the heel of the foot. It has articulations for attachment of the calcaneal tendon (Achilles’ tendon) on its posterior surface. On its medial surface it contains the sustentaculum tali – a shelf of bone projecting medially and supporting the posterior part of the talus. The plantar surface of the bone contains the calcaneal tuberosity. The intermediate tarsal bone is the:  Navicular: a boat shaped bone on the medial side of the foot. It articulates with the talus and has a rounded tuberosity which is an attachment site for the tibialis posterior tendon. The distal group contains:  Cuboid: in front of the caclaneus.  Cuneiforms: there are 3 cuneiforms, lateral, intermediate and medial, they are in front of the navicular bone and behind the metatarsals. Metatarsals: the metatarsals articulate with the tarsals and the proximal phalanges. They consists of base, shaft, head and neck. N.B. – the tuberosity on the base of the 5th which articulates with the cuboid Phalanges: there are 3 phalanges for each toe: proximal, middle and distal apart from the great toe (big toe) which has 2 – a proximal and distal)

The Popliteal Fossa – the gateway to the lower limb. It is a diamond shaped fossa on the back of the knee formed by:  Superolaterally – biceps femoris  Superomedially – semimembranosus  Inferolaterally – lateral head of gastrocnemius  Inferomedially – medial head of gastrocnemius  Posteriorly – skin and fascia  Anteriorly – the femur The contents of the popliteal fossa are:  Popliteal artery  Popliteal vein  The tibial and common peroneal nerves – the tibial nerve runs straight, the peroneal nerve runs to the side before running round the neck of the fibula  Short saphenous vein  Popliteal lymph nodes Joints of the Region Knee joint: the largest synovial joint in the body. It consists of the articulation between the femur and the tibia (weight bearing) and the articulation between the patella and the femur. There are 3 main compartments to the knee: the medial compartment, lateral compartment and patello-femoral compartment. • The distal femur:  Articular condyles – articulate with the tibia, medial is bigger than lateral  The patella articulates anteriorly  The linea aspera provides the attachment for vastus and biceps femoris • Proximal tibia:  The articular surfaces receive the femoral condyles  Intercondylar eminence provides attachment for cruciate ligaments and menisci  Tibial tuberosity provides attachment for the patellar ligament • Proximal fibula:  The head articulates with the tibia • Patella – a sesimoid bone in the tendon of quadriceps femoris It is held in place by the two menisci one on each side between the femoral condyles. The medial and lateral menisci form partial cushions between tibia and femur and are attached to the intercondylar eminence of the tibia. The medial meniscus is commonly injured in twisting, more commonly than lateral It is essentially a hinge joint which involves flexion and extension. It can also when the joint is extended to assist with standing. It contains a number of different ligaments: - Patellar ligament: attaches from patella to tibial tuberosity - Collateral ligaments: stabilise the hinge-like motion of the knee; there are 2, a fibular collateral ligament which attaches from the lateral femoral epicondyle to the lateral fibular head; and the tibial cruciate ligament which attaches from the medial femoral epicondyle to the medial condyle of the tibia. o The medial collateral is a broad flat thickening of the knee capsule and is attached to the medical meniscus. Prevents knee abduction o Lateral collateral is a cord like ligament and is not attached to either the knee capsule or lateral meniscus. Prevents knee adduction

Cruciate ligaments: there are 2; anterior and posterior, both attach from the intercondylar area at the back of the tibia, to the intercondylar area of the femur. o Anterior cruciate is attached to the intercondylar area of tibia and passes upwards, backwards and laterally. Limits anterior movement of the tibia on the femur (or posterior movement of the femur on the tibia). We can live without it o Posterior cruciate is attached to the posterior intercondylar area of the tibia and lateral meniscus. It passes upwards, forwards and medially. It prevents posterior movement of the tibia on the femur and vice verse. It takes the weight of the body when the knees are bent – so it is important -

Bursae around the knee: - bags of synovial membrane and fluid found between tendons or muscles and skin  Pre-patellar bursa   

Pre-patellar tendon bursa  Popliteal bursa (Baker’s cyst) Interosseous Membrane: this is a tough fibrous membrane that connects the tibia and fibula. It has two apertures, one at the proximal end for the anterior tibial vessels and one at the distal end for the fibular artery. There are also two tibiofibular ligaments at the distal end of the two bones, anterior and posterior Ankle Joint: A hinge synovial joint between the medial malleolus of the tibia, lateral malleolus of the fibula and talar dome of the talus that only plantarflexion or dorsiflexion. The joint is stabilised by the medial and lateral ligaments: - The lateral ligament complex – calcaneofibular, anterior talofibular and posterior talofibular. The anterior talofibular ligament most often sprained - The medial or deltoid ligament of the ankle – from the medial malleolus the medial ligament spreads out as a triangle. The superficial part goes and down and

back to the tail of the calcaneus, the deep part goes backwards and downwards along the entire length od the sustentaculum tali The articular surface of the talus is wider at the front than the back so in dorsiflexion the joint is more stable than in plantar flexion. Eversion and Inversion do not occur at the ankle joint but at the sub-talus joint Intertarsal Joints: these joints are used in eversion or inversion of the foot, (rocking the sole of the foot) and supination and pronation (rotating the foot). ⊕ The foot is divided into the hind foot, mid foot and fore foot ⊕ The sub-talar joint consists of: o The talo-calcaneal joint – anterior to the head of the talus o The talo-navicular joint o The calcaneo-cuboid joint – a separate joint cavity but a functional unit with the talo-calcaneal joint ⊕ The mid-tarsal joint consists of joints between the midtrasal bones and the metatarsals Tarsometatarsal joints: limited sliding movement Metatarsophalangeal joints: allow extension, flexion, adduction, abduction, rotation and circum duction of the toes. Interphalangeal joints: held in place by collateral ligaments.

Muscles of the Region Superficial Posterior Compartment – plantar flexors (foot down) Muscle Origin Gastrocnemius Medial head-posterior surface of distal femur just superior to medial condyle; lateral head-upper posterolateral surface of lateral femoral condyle

Insertion Innervation Via calcaneal tendon, Tibial nerve to posterior surface of [S1,S2] calcaneus

Function Plantarflexes foot and flexes knee

Plantaris

Inferior part of lateral supracondylar line of femur and Via calcaneal tendon, Tibial nerve oblique popliteal ligament of knee to posterior surface of [S1,S2] calcaneus

Plantarflexes foot and flexes knee

Soleus

Soleal line and medial border of tibia; posterior aspect Via calcaneal tendon, Tibial nerve of fibular head and adjacent surfaces of neck and to posterior surface of [S1,S2] proximal shaft; tendinous arch between tibial and calcaneus fibular attachments

Plantarflexes the foot

NB: Gastrocnemius is superficial to soleus (the main two muscles), they come together to form the Achilles heel

Deep Posterior Compartment Muscle Popliteus

Origin Insertion Posterior surface of proximal tibia Lateral femoral condyle

Innervation Tibial nerve [L4 to S1]

Function Unlocks knee joint (laterally rotates femur on fixed tibia)

Flexor hallucis longus

Posterior surface of fibula and Plantar surface of distal adjacent interosseous membrane phalanx of great toe

Tibial nerve [S2,S3]

Flexes great toe

Flexor digitorum longus

Medial side of posterior surface of Plantar surfaces of bases of Tibial nerve the tibia distal phalanges of the [S2,S3] lateral four toes

Flexes lateral four toes

Tibialis posterior

Posterior surfaces of interosseous Mainly to tuberosity of membrane and adjacent regions navicular and adjacent of tibia and fibula region of medial cuneiform

Inversion and plantarflexion of foot; support of medial arch of foot during walking

Tibial nerve [L4,L5]

Lateral Compartment – ankle evertors (sole of foot away from midline) Muscle Fibularis longus

Origin Upper lateral surface of fibula, head of fibula and lateral tibial condyle

Insertion Innervation Undersurface of lateral sides of distal Superficial fibular end of medial cuneiform and base of nerve [L5,S1,S2] metatarsal I

Function Eversion and plantarflexion of foot; supports arches of foot

Fibularis brevis

Lower two-thirds of lateral surface of shaft of fibula

Lateral tubercle at base of metatarsal Superficial fibular V nerve [L5,S1,S2]

Eversion of foot

Anterior Compartment – plantar flexors (foot up) Muscle Tibialis anterior

Origin Lateral surface of tibia and adjacent interosseous membrane

Insertion Innervation Medial and inferior surfaces of Deep fibular medial cuneiform and adjacent nerve [L4,L5] surfaces on base of metatarsal I

Function Dorsiflexion of foot at ankle joint; inversion of foot; dynamic support of medial arch of foot

Extensor hallucis longus

Middle one-half of medial surface of fibula and adjacent surface of interosseous membrane

Dorsal surface of base of distal Deep fibular phalanx of great toe nerve [L5,S1]

Extension of great toe and dorsiflexion of foot

Extensor digitorum longus

Proximal one-half of medial Via dorsal digital expansions surface of fibula and related into bases of distal and middle surface of lateral tibial condyle phalanges of lateral four toes

Fibularis tertius

Distal part of medial surface of Dorsomedial surface of base of Deep fibular fibula metatarsal V nerve [L5,S1]

Deep fibular nerve [L5,S1]

Extension of lateral four toes and dorsiflexion of foot Dorsiflexion and eversion of foot

Intrinsic Foot Muscles Dorsal Aspect of the Foot Muscle Extensor digitorum brevis

Origin Superolateral surface of the calcaneus

Insertion Innervation Base of proximal phalanx of great Deep fibular toe and lateral sides of the tendons nerve [S1,S2] of extensor digitorum longus of toes II to IV

Function Extension of metatarsophalangeal joint of great toe and flexion of toes II to IV

Sole of Foot

First Layer Muscle Abductor hallucis

Origin Insertion Medial process of calcaneal tuberosity Medial side of base of proximal phalanx of great toe

Innervation Function Medial plantar nerve Abducts and flexes great toe from the tibial nerve at metatarsophalangeal joint [S2,S3]

Flexor digitorum brevis

Medial process of calcaneal tuberosity Sides of plantar and plantar aponeurosis surface of middle phalanges of lateral four toes

Medial plantar nerve Flexes lateral four toes at from the tibial nerve proximal interphalangeal joint [S2,S3]

Abductor Lateral and medial processes of Lateral side of base of Lateral plantar digiti minimi calcaneal tuberosity, and band of proximal phalanx of nerve from tibial connective tissue connecting calcaneus little toe nerve [S2,S3] with base of metatarsal V

Abducts little toe at the metatarsophalangeal joint

Second Layer Muscle Origin Quadratus Medial surface of calcaneus and plantae lateral process of calcaneal tuberosity

Insertion Innervation Lateral side of Lateral plantar nerve from tendon of flexor tibial nerve [S1 to S3] digitorum longus in proximal sole of the foot

Function Assists flexor digitorum longus tendon in flexing toes II to V

Lumbricals First lumbrical-medial side of tendon of flexor digitorum longus associated with toe II; second, third, and fourth lumbricalsadjacent surfaces of adjacent tendons of flexor digitorum longus

Medial free margins of extensor hoods of toes II to V

Flexion of metatarsophalangeal joint and extension of interphalangeal joints

First lumbrical-medial plantar nerve from the tibial nerve; second, third, and fourth lumbricals-lateral plantar nerve from the tibial nerve [S2,S3]

Third layer Muscle Flexor hallucis brevis

Origin Plantar surface of cuboid and lateral cuneiform; tendon of tibialis posterior

Insertion Lateral and medial sides of base of proximal phalanx of the great toe

Innervation Lateral plantar nerve from tibial nerve [S1,S2]

Adductor hallucis

Transverse head-ligaments associated with metatarsophalangeal joints of lateral three toes; oblique head-bases of metatarsals II to IV and from sheath covering fibularis longus

Lateral side of base of proximal phalanx of great toe

Lateral plantar Adducts great toe at nerve from tibial metatarsopha-langeal joint nerve [S2,S3]

Flexor digiti Base of metatarsal V and related sheath of minimi fibularis longus tendon brevis

Function Flexes metatarsophalangeal joint of the great toe

Lateral side of Lateral plantar Flexes little toe at base of proximal nerve from tibial metatarsophalangeal joint phalanx of little toe nerve [S2,S3]

Fourth layer Muscle Origin Insertion Dorsal Sides of adjacent Dorsal expansions interossei metatarsals and bases of proximal phalanges of toes II to IV

Innervation Function Lateral plantar nerve from tibial Abduction of toes II to IV at nerve; first and second dorsal metatarsophalangeal joints; resist extension interossei also innervated by of metatarsophalangeal joints and flexion of deep fibular nerve [S2,S3] interphalangeal joints

Plantar Medial sides of interossei metatarsals of toes III toV

Lateral plantar nerve from tibial Adduction of toes III to V at nerve [S2,S3] metatarsophalangeal joints; resist extension of the metatarsophalangeal joints and flexion of the interphalangeal joints

Dorsal expansions and bases of proximal phalanges of toes III to V

Vessels of the Region Popliteal artery: this is the major blood supply to the leg and foot and enters the posterior compartment of the leg from the popliteal fossa. It becomes the popliteal artery from the femoral artery and has 3 major branches. Peroneal artery: which runs in lateral compartment of the leg Anterior tibial artery: passes forward thorough the aperture of the interosseous membrane and supplies the anterior compartment of the leg. In the foot is forms the dorsalis pedis artery. Posterior tibial artery: descends through the deep region of the posterior compartment. It supplies both the lateral and posterior compartments of the leg. It splits in just inferior to the knee into the: - circumflex fibular artery - anastomosis with vessels surrounding the knee - fibular artery – supplies the posterior compartment of the leg, it also sends of a perforating branch which anastomosis with a branch of the anterior tibial artery. The posterior tibial artery enters the foot through the tarsal tunnel. This is a palpable spot because the artery is not covered by very much. It bifurcates into lateral and medial plantar arteries. The lateral plantar artery forms the deep plantar arch. These go on to supply the plantar side of the toes. Dorsalis Pedis: a continuation of the anterior tibial artery. It enters the foot after passing the ankle joint. It passes inferiorly into the deep plantar arch between the first and second metatarsal. Its pulse is palpable on the dorsal surface of the foot in between the metatarsals of the first and second toe.

Deep Veins: the deep veins of the leg generally follow the arteries and eventually drain in to the great and small saphenous vein which drains into the femoral vein. They consists of the: posterior tibial veins, dorsal digital veins, popliteal vein and the perforating veins through which blood passes from superficial to deep. The deep system forms a powerful muscle pump in the calf Dorsal Venous Arch: connect the great and small saphenous veins in the foot. ⊕ From the medial aspect of the dorsal venous arch runs the long saphenous vein – lies 2cm above and 2cm medial to medial malleolus. It runs in the medial aspect of the leg, behind the knee and empties into the femoral vein at the sapheno-femoral junction in the groin. In the leg it anastomoses freely with the short saphenous vein and has connecting veins to the deep system ⊕ From the lateral aspect of the dorsal venous arch runs the short saphenous vein. It runs posterior to the lateral maleolus, up the back of the calf and drains into the deep system and popliteal vein in the popliteal fossa

Nerves of the Region Segmental motor supply: • Hip flexors – L23 • Hip extensors – L45 • Knee extension – L34 • Knee flexion – L5S1 • Ankle dorsiflexion – L45 • Ankle plantaflexion – S12 • Think patterns in walking – walking starts at the top and passes down the lumbro-sacral region Segmental Sensory Supply: • Regular dermatomal supply • L3 to knee, L4 to floor • L5 to the dorsum of the great toe • S1 to lateral side of foot • S1 to sole of foot Tibial Nerve: this is the nerve that mainly associated with the posterior compartment of the leg. It is a branch of the sciatic nerve which descends in to the posterior compartment from the popliteal fossa. It also supplies the skin on the lower posterolateral surface of the leg and the lateral side of the foot and little toe. When it reaches the foot is splits into a - medial plantar nerve which is sensory for the sole of the foot - lateral plantar nerve which supplies motor fibres to the intrinsic muscles of the sole – the plantar flexors. Superficial Fibular Nerve: this supplies the lateral compartment of the leg and originates as one of the two branches from the common fibular nerve (originating from the sciatic nerve). Deep fibular nerve: this supplies the anterior compartment of the leg and continues onto the foot where it innervates the dorsal flexors of the foot. Gait Gait can be divided into the swing phase and stance phase. The swing phase = 1/3 of cycle, the stance phase 2/3

Limbs 8 - Lower limb Nerves and Vessels Anil Chopra

1. Summarise and demonstrate the arterial supply and venous drainage of the lower limb 2. Review the techniques of palpation of the femoral, popliteal, posterior tibial and dorsalis pedis arteries 3. Explain the likely causes and consequences of embolism in the lower limb 4. Explain the term intermittent claudication 5. Explain the causes and likely consequences of compartment syndromes, giving appropriate examples 6. Explain the mechanism for venous return from the lower limb in terms of superficial and deep veins, perforators, valves and the muscle pump 7. Explain how varicose veins arise in the lower limbs and how they may lead to venous circulatory incompetence 8. Describe the common sites and causes of deep venous thrombosis and outline its possible consequences 9. Discuss the anatomical basis of canulation of the femoral vein and arterial access to the femoral artery in the groin. 10. Describe how to perform a cut-down of the long saphenous vein at the ankle, including its anatomical landmarks and clinical importance Neuroanatomy of the Lower Limb There are 2 types of nerve distribution, both of which can be damaged: Segmental: part of the spinal cord that can be damaged by lesions Peripheral: part of the separate peripheral nerves themselves which can be damaged by surgery, laceration, limb injury. The lower limb undergoes extension and internal rotation, therefore the extensor muscles are anterior and the flexor muscles are posterior: HIP KNEE ANKLE L2} FLEX L3} L4} EXTEND L5}

L3} EXTEND L4} L5} FLEX S1}

L4} D-FLEX L5} S1} P-FLEX S2}

The segmental dermatomes are as follows: L3 – front of the thigh (“L3 to the knee”) L4 – front of the leg (“L4 to the floor”) L5 – dorsum of the great toe

S1 – lateral aspect of the foot S2-4 – perineum and perianal region There are 2 main reflex arcs in the knee that are controlled by segemental neves: - Knee jerk: L3 - Ankle jerk: S1 The different peripheral nerves all arise from the lumbosacral plexus: - The iliohypogastric and ilio-inguinal nerves (L1) - The genitofemoral nerve (L1L2) - The lateral cutaneous nerve of the thigh (L2L3) - The femoral nerve (L2L3L4, posterior divisions) - The obturator nerve (L2L3L4, anterior divisions) - The lumbosacral trunk (L4L5) – feeds the sacral plexus - The Sciatic Nerve (L4L5S1S2S3) - The nerve to piriformis (S1S2) - The posterior cutanous nerve of the thigh (S1S2S3) - The pelvic splanchnic nerves (S2S3S4) – parasympathetic - The pudendal nerve (S2S3S4) - The nerve to nerve to obturator internus (L5S1S2) - The superior gluteal nerve (L4L5S1) - The inferior gluteal nerve (L5S1S2) Clinical Neurological Problems with Lower Limb

Injury to the Femoral Nerve The femoral nerve is relatively superficial in the groin but is rarely damaged except by doctors (iatrogenic injuries). The commonest injury today is via traction injuries during hip replacements, and also at laparoscopic repair of inguinal hernias. It can also be damaged during erroneous attempted cannulations of the femoral artery or femoral vein. The Lateral Cutanous Nerve of the thigh This superficial nerve passes 2cm medial to the anterior superior iliac spine at the level of the inguinal ligament. It can be compressed at this level causing meralgia paraesthetica. The obturator nerve The obturator nerve is rarely damaged. Beware pain in the distribution of the obturator nerve as it can be indicative of malignant disease in the pelvis. Injury to the superior gluteal nerve The superior gluteal nerve supplies the gluteus medius and gluteus minimus muscles. If this nerve is damaged, the result is a Tredelenberg gait, where the pelvis lurches during gait. The commonest injury today to the superior gluteal nerve is at hip replacement. The nerve lies approximately 5cm proximal to the tip of

the greater trochanter, and approaches to the hip joint should not extend more than 5cm from the tip of the greater trochanter. Injury to the sciatic nerve ⊕ The commonest cause today of injury to the sciatic nerve is after hip replacement. The common peroneal division is far more vulnerable than the tibial division. ⊕ Can result in the flaccid paralysis of hamstrings, paralysis of all muscles below the knee and loss of most sensation below the knee. ⊕ To avoid damage to the sciatic nerve, always give an intramuscular injection in the upper outer quadrant of the buttock. Keep away from the lower inner quadrant, which is where the nerve is most likely to be situated. ⊕ Other causes of damage are trauma (e.g. hip dislocations or acetabular fractures) and pelvic disease. Injury to the common peroneal nerve As well as being damaged at the level of the hip, the common peroneal nerve is highly vulnerable to damage at the level of the fibular neck, around which the nerve winds. Results in paralysis of extensor and peroneal compartment of leg results in foot drop accompanied by loss of sensation over most of antero-lateral leg and dorsum of foot. Causes of damage are trauma, knee replacement and external pressure e.g. from plasters or during surgical procedures. Injury to the saphenous nerve Injury to this nerve is surprisingly common. The nerve can be damaged at the medial malleolus (e.g. after varicose vein surgery or cut down) or at the level of the knee (e.g. ACL surgery). Compression of the spinal roots Often results after lumbar disc injury – pain is felt down route of affected nerve. L4 or L5 is common leading to sciatica Anaesthetic Nerve Blocks Nerve blocks can be utilised by anaesthetists to aid or substitute general anaesthesia during surgery. Examples include femoral nerve blocks, sciatic nerve blocks, ankle blocks or blocks of the lateral cutaneous nerve of the thigh. Knowledge of peripheral anatomy allows the anaesthetist to localise the best place to insert local anaesthetic and also to predict the level and extent of anaesthesia provided. Vascular Problems with the Lower Limb Femoral hernias Pass into the femoral canal which is medial to the femoral vein in the femoral sheath Cannulation of the femoral artery and vein The femoral artery and vein can be easily exposed and cannulated at the groin e.g. for cardiac arteriography (artery) or for resuscitation (vein).

Cut-down at the medial malleolus of the long saphenous vein. In the shocked patient, venous cannulation may not be easy or possible. The anatomical surface marking of the long saphenous vein at the ankle (2cm above and proximal to the tip of the medial malleolus) makes it an excellent site to perform a “cut-down”. A small incision can be made at the ankle and a venous cannula placed under direct vision into the vein for resuscitation. The concept of arterial embolism Acute arterial embolism can be caused by sudden occlusion of an atheroclerotic vessel or by thrombus from atrial fibrillation. If a vessel is suddenly occluded with no time for a collateral circulation to develop, the consequences can be severe. For example if an arterial clot forms in the popliteal artery, there may be no time for a collateral circulation to develop and the leg may become ischaemic and require amputation if the lesion is no cleared within a few hours. Intermittent claudication is a condition where there is a gradual occlusion of arteries within the limb, usually atherosclerotic. The muscles supplied distal to the occlusion become deprived of blood on exercise so that there is a limited walking distance before pain occurs, most commonly in the calf, but sometimes in the thigh or buttock. Compartment syndrome Compartment syndromes can occur anywhere in the leg but are most common in the true leg itself. There are three compartments in the leg, the anterior, posterior and lateral compartments. Each compartment is bound by a very tight fascia, which only let the enclosed muscles swell to a certain degree before resisting any further expansion and then increase the pressure in the muscle itself. If the pressure in the muscle increases too far, the arterial supply and venous return of the muscle in that compartment is cut off, resulting in muscle death, with resulting loss of movement and contractures in the limb. There are clinical syndromes where muscle swelling causes such damage, and these are termed compartment syndromes. Acute compartment syndrome occurs after trauma to a limb, e.g. fractures, muscle damage. Unless the fascia is released urgently by a fasciotomy the muscle will die with disastrous consequences. Note that the arterial pulse is not lost in acute compartment syndromes. The tissue pressure is only 25mmHg and pressure need only to rise to 50-60mmHg to cause a compartment syndrome. The diastolic blood pressure is 80mmHg and the systolic 120mmHg! Chronic compartment syndrome occurs in athletes where the muscles swells during exercise and causes activity-related pain. Elective fasciotomy can relieve the pain of this condition.

Varicose veins and deep venous insufficiency As explained above, the superficial veins in the limb have valves which prevent backflow of blood. However, as well as this, the deep veins and the perforating veins also have valves. Probably the most important valve is at the sapheno-femoral junction in the groin. If this valve is incompetent, then blood can easily flow back into the superficial venous system, causing varicose veins. Most operations for varicose veins involve tying off the sapheno-femoral junction. Varicose veins are dilated and tortuous superficial veins. They can be painful, causing an aching discomfort on standing. However, they are also pathological in that the increased pressure within the superficial venous system can cause increased pressure in the superficial circulation, causing skin changes (lipodermatosclerosis) and often skin ulcers. Most skin ulcers are due to venous insufficiency of this type. Deep venous thrombosis Blood can clot (thrombose) in the superficial and deep veins of the lower limb. When it occurs in the deep veins, this is termed deep venous thrombosis (DVT). DVT is often “silent” but may present with pain and swelling in the calf or the proximal thigh. A distal DVT occurs in the calf whilst a proximal DVT extends into the thigh and pelvis. A proximal DVT is very dangerous, as there is a high risk of propagation of the clot into the lungs. DVT is very important clinically. It can occur idiopathically (i.e. without an obvious cause) but is often associated with immobility, trauma, surgery within the abdomen, pelvis or limbs, obesity, malignancy, pregnancy or with the use of the oral contrceptive pill. DVT has two main consequences; a. the clot may propagate into the pulmonary circulation, causing a pulmonary embolus (PE). A PE may be fatal and for this reason DVT’s are usually treated by anticoagulation to prevent this complication occurring. b. The clot in the deep veins may cause increased back pressure in the deep veins, causing venous insufficiency and leg ulcers (the post-phlebitic syndrome) The superficial veins may also clot or become inflamed/infected. This causes superficial thrombophlebitis. This is not so dangerous as DVT but can be very painful. The treatment is usually symptomatic (analgesia, rest, ice etc) rather than with anticoagulation. The superficial veins as grafts in elective surgery The saphenous veins are often used in cardiac and vascular surgery as grafts to replace arteries. Obviously the veins need to be orientated correctly due to the valves present within them. As there is such an excellent anastomosis in the leg, the removal of the superficial veins rarely causes a problem.

Femoral Triangle The femoral triangle is outlined by; » Superiorly – the inguinal ligament » Medially – by the adductor longus » Laterally – by the sartorius The femoral triangle contains the femoral nerve, artery and vein, which are arranged as follows, from lateral to medial;  Femoral Nerve  Femoral Artery  Femoral Vein The femoral sheath encloses the femoral artery and vein (but not the femoral nerve). A portion of it medially forms the femoral canal.

Lower Limb Pulses