Hip Flexion ROM

HIP FLEXION

BY ANTHONY LETT

The focus of this article is on hip flexion with the knee flexed.

With the knee flexed the hamstrings are taken out of the equation to a large extent. The “normal ‘range is said to be around 120 degrees, although this will vary depending on the text you read.

The limitations to further range of motion consist of: apposition of thigh on abdomen, bony/joint configuration, inferior and posterior joint capsule, and muscle tension/stiffness in the gluteus maximus, and adductors, in particular the posterior head of the adductor magnus.

The adductor magnus and the gluteus maximus have the greatest cross-sectional areas of all the extensors.

IMAGE 1

The adductors The posterior head of the adductor magnus consists of a thick mass of fibers arising from the region of the pelvis adjacent to the ischial tuberosity. From this posterior attachment the fibers run vertically and attach as a tendon on the adductor tubercle on the medial side of the distal femur. Because of location, innervation, and action similar to those of the hamstring muscles, the posterior head is often referred to as the extensor head of the adductor magnus. See Image one.

Note the posterior head of adductor magnus (deep to the hamstrings) on the medial side of the opening that allows for the passage of the femoral artery.

IMAGE 2

The anterior head of the adductor magnus has two sets of fibers: horizontal and oblique. The small set of horizontally directed fibers crosses from the inferior pubic ramus to the proximal end of the linea aspera and is often called the adductor minimus.

The larger obliquely directed fibers run from the ischial ramus to nearly the entire length of the linea aspera, as far distally as the medial supracondylar line.

See Image two

Saggital plane function The adductor muscles have leverage as significant flexors or extensors of the hip. The exception is within an arc of about 40 to 70 degrees of hip flexion when the line of the adductor muscles (excluding the posterior head of magnus) runs directly through or close to the medial-lateral axis of rotation of the hip. At this point, the adductor muscles lose their potential to produce any torque in the sagittal plane.

With the leg/hip flexed outside of the 40 to 70 degree arc, the line of force of the adductors is well posterior to the mediallateral axis of the joint. At this position the adductors have an extensor moment arm and are capable of generating an extension torque—similar to the posterior head of the adductor magnus.( Regardless of hip position, the posterior fibers of the adductor magnus are powerful extensors of the hip, similar to the hamstring muscles.)

Because the adductor muscles are one joint muscles, and given their significant leverage as extensors of the hip, limitation experienced at the posterior aspect of the thigh in hip flexion is very likley to arise from the addcutor muscles as opposed to the two joint hamstrings.

IMAGE 3

Gluteus Maximus.

The gluteus maximus has numerous proximal attachments from the posterior side of the ilium, sacrum, coccyx, sacrotuberous and posterior sacroiliac ligaments, and adjacent fascia. The muscle attaches into the iliotibial band of the fascia lata (along with the tensor fasciae latae), and the gluteal tuberosity on the femur. The gluteus maximus is a primary extensor and external rotator of the hip. The muscle fibers and attachement on the gluteal tuberisoty will be strongly stretched during hip flexion.

See image three

The Lunge The lunge, image 4, as we have seen previously, serves as a useful test for the one joint hip flexors, inside of the pelvic bowl in yellow. In fact, the lunge is very often a compound stretch, meaning it effects multiple muscles and joints.

IMAGE 4

The adductor magnus and gluteus maximus can be seen stretching on the underside (posterior aspect) of the front leg. The ROMA test can be viewed as a reproduction of this stretch performed with the client lying prone.

IMAGE 5

IMAGE 6

Bony/joint compression is an issue that may affect the hip flexion test. There is wide variation in the shape and orientation of the acetabulum and the head and neck of the femur. Note the variation in images 5 and 6 above. If compression or impingement occurs, clients will report discomfort around the ASIS and AIIS. Adaptations for testing will be discussed in class.

Watch video Finally, note the stretch of the gluteus maximus and adductor magnus in the video.

Click image above to play video