ANKLE ROM BY ANTHONY LETT
In this post we will be looking at the foot and ankle region with a focus on range of movement.
Part A: Anatomy First, take five minutes to watch this excellent video about the anatomy and kinesiology of the ankle joint: https://www.youtube.com/watch?v=4hCS1O2LP_c.
Flexion Extension
Pronation Sole faces in
Supination Sole faces out
Although it is not often made clear (for example in the image below) planter and dorsi flexion are the only movements that occur at the ankle or talocrural joint. Inversion and eversion occur at the intertarsal joints, and the talus moves very little. The most important intertarsal joints for inversion and eversion are the subtalar, the talocalcaneonavicular, and the calcaneocuboid.
Anatomy and function The foot and ankle is an exceedingly complex region. Twenty-eight individual muscles, acting across 32 joints or joint complexes, control the movement and posture of the ankle and foot. There are 4 layers of intrinsic muscles that originate and insert within the plantar aspect (underneath) of the foot. There are 3 compartments of extrinsic muscles, all which encase multiple muscles within. Because all extrinsic muscles cross multiple joints, they possess multiple actions.
The plantar fascia is located just superficial to the first layer of muscles.
The muscles of the ankle and foot not only control the specific actions of the underlying joints, but also provide the stability, push off and shock absorption necessary for locomotion. In the “take -off “phase of gait for example, the foot must be stiff to act as a rigid lever for propulsion. When landing, the foot pronates and “unlocks,” becoming a flexible structure to allow for small movements between the tarsals and movement of the forefoot relative to the rearfoot. None of this can occur if the foot is stiff!
Extrinsic Muscles
Anterior Compartment There are four muscles of the anterior compartment. All four “pretibial� muscles are dorsiflexors. The tibialis anterior (image 1B) also inverts and adducts the foot as well as providing secondary support to the medial longitudinal arch. The extensor digitorum longus (image 1A) and Peroneus tertius evert the foot. IMAGE 1A
IMAGE 1B
Lateral Compartment The peroneus longus (see image 2 below in green as it assists with plantar flexion) and peroneus brevis (also known as fibularis) muscles are the primary evertors of the foot. These muscles provide the main source of active stability to the lateral side of the ankle. Both muscles are also plantar flexors of the talocrural/ankle joint. IMAGE 2
Posterior Compartment
IMAGE 3
The muscles of the posterior compartment are divided into two groups. The superficial group (see image 3) includes the gastrocnemius, soleus (together known as the triceps surae), and plantaris. The deep group includes the tibialis posterior, flexor digitorum longus, and flexor hallucis longus, located deep to the soleus muscle. In addition to plantar flexion and supination/inversion, the flexor digitorum longus and flexor hallucis longus have additional flexor actions at the more distal joints of the foot at the metatarsophalangeal and interphalangeal joints.
IMAGE 4
The peroneus longus and tibialis posterior and anterior form a sling that supports the transverse and medial longitudinal arches. Their attachments on the underneath of the foot (in image four) indicate their role in providing arch support.
The multiplicity of roles of the extrinsic muscles, increases the complexity of analyzing movement. In gait for example, the muscles may be performing one or many of the following actions: deceleration and control of supination or pronation, fixation, counterbalancing/neutralizing the pull other muscles, support of the transverse and medial longitudinal arches, transference of body weight and absorption of some of the impact of loading.
Part B: The importance of flexibility
Adequate flexibility is essential for the daily life movements of squatting, walking and running. When the calf muscles are tight for example, the foot must pronate in order to unlock the midtarsal joints to increase apparent (but not true) dorsiflexion. This excessive pronation can increase injury risk at the knee and foot. A study in 1997 (molnar and Esterson) demonstrated that because of repetitive plantar flexion, 67% of elite ballet dancers
lacked the normal 10% dorsi flexion required for normal walking gait. The follow up study reported leg injuries correlating significantly with those dancers with low dorsi flexion values. Injuries included plantar fasciitis, midfoot joint strain and Achilles tendinitis. Important to keep in mind in ROM testing is that plantar flexion range is not just from the ankle joint. The contribution of the subtalar, midtarsal, and MTP joints is estimated to be between 10 and 40% of total plantar flexion range. So, we need to stretch the foot and its joints in its entirety!
Impingement In testing ROM, we must be considerate of the possibility of bone compression. Compression or impingement occurs where two bones abut each other and restrict further movement. An example is locking out the elbow joint when straightening the arm. When compression occurs, no further movement is available. It is not dangerous unless repeated constantly, whereupon osteophytes may form. Compression will result in sensations that are different to stretching and will occur at the opposite side of the joint to where the stretch would occur. For example, a stretch for the calf muscles would be experienced at the posterior aspect of the ankle joint. Compression sensations would be experienced at the anterior aspect of the joint.
IMAGE 5
Image five, with the talus highlighted in blue.
IMAGE 6
Posterior compression occurs when the posterior portion of the talus impinges on the posterior aspect of the tibia.
Anterior Compression during planter flexion occurs between the front of the lower tibia and a sulcus, or depression on the talar neck, or the talus itself. See neck of Talar in image 6, highlighted in pink. Bone spurs may also form in the region and need to be removed surgically. See Image 7.
IMAGE 7
Compression may not necessarily be experienced on both limbs because of normal variation. Although further stretching is not possible, the lesson is that a “one size fits all” approach to assessment, stretching, and exercise in general, is flawed.
How to stretch some of the compartments of the leg. Enjoy the stretches below from my book “Stretching on the Pilates reformer: Essential cues and images,” on Amazon books. I have included a strong stretch for the two posterior compartments, a stretch that isolates the soleus, a stretch for the lateral compartment and one for the anterior compartment. Practice them regularly!
For a copy of my book, click here.
The Kneeling Calves • Standard: Advanced • Spring Tension: Medium • Muscle Emphasis: Entire calf group, hamstrings, gluteus maximus
A
A & B. How to stretch Kneel on carriage and straighten one leg. Press carriage away a little with the other leg. Lower heel that is on the bar. Clasp bar. Lift chest to straighten spine if possible.
B
B. How to contract Press thigh down into bar and ball of foot of front leg into bar.
B & C. How to restretch Lift chest. Bend elbows to pull chest toward leg and lower heel further under bar if possible.
C
What to watch out for: • Bending the stretching leg. • Spine rounding/flexing.
The Lying Peroneals • Standard: Any • Spring Tension: Light - Medium • Muscle Emphasis: Peroneal muscle group
A
A & B. How to stretch Press carriage away a little to slacken rope. Take one leg up as pictured and insert foot into strap. Roll ankle inward (invert the foot). Pull down on strap gently.
B
B. How to contract Press foot back toward neutral position.
C
B & C. How to restretch Pull down on strap. Take leg across body.
The Standing Soleus • Standard: Any • Muscle Emphasis: Soleus, tibialis posterior
A
A. How to stretch Place ball of one foot onto foot bar. Lower heel. Lean over thigh so that chest contacts thigh. Use arms to pull chest strongly onto thigh causing heel to lower and foot to dorsi flex.
A. How to contract Press ball of foot into bar as if to accelerate.
B
B. How to restretch Bend elbows to pull chest onto leg with more force. Lower heel as much as possible.
The Lying Peroneals 2.0 • Standard: Any • Spring Tension: Medium - Heavy • Muscle Emphasis: Entire lateral/peroneal compartment
A
A. How to stretch
Press carriage away and place outside of one foot onto jump board. Bend other knee slowly, controlling carriage movement with this leg. As carriage slides in, allow foot to invert/ankle to “roll in”.
A. How to contract: Try to turn foot back toward neutral position; i.e. evert the foot.
B
B. How to restretch
Allow support leg to bend further and carriage to travel in further. Allow foot to invert further.
What to watch out for: • Losing control of carriage movement. • Moving into stretch too quickly, “bouncing.”
The Lying Tib Ant • Standard: Any • Spring Tension: Medium - Heavy • Muscle Emphasis: Entire anterior compartment including tibialis anterior, extensor hallucis and digitorum longus and brevis
A
A. How to stretch
Press carriage away and place top of one foot onto Jump board. Bend other knee slowly, controlling carriage movement with this leg. As carriage slides in allow foot and toes to plantar flex.
A. How to contract: Press foot back into jump board toward neutral position i.e. dorsi flex the foot.
B
B. How to restretch
Allow leg to bend further and carriage to travel in further. Allow foot to plantar flex further.
What to watch out for: • Losing control of carriage movement. • Moving into stretch too quickly, “bouncing.”