Hip Flexors, Part 2
The Sartorius Muscle


Function
The Sartorius muscle is not only the longest muscle in the human body but also the only muscle that stretches over two joints.
Effectively helping in moving the hip and knee. While at the hip, it can flex, abduct(opening the legs), and laterally rotate the thigh, it can only flex (bend) the knee. As all all of its actions are weak, the sartorius is considered a synergist muscle.

Where
Generally speaking he sartorius muscle originates from the anterior superior iliac spine and part of the notch between the anterior superior iliac spine and anterior inferior iliac spine . It runs obliquely across the upper and anterior part of the thigh in an inferomedial direction. It passes behind the medial condyle of the femur to end in a tendon. This tendon curves anteriorly to join the tendons of the gracilis and semitendinosus muscles in the pes anserinus, where it inserts into the superomedial surface of the tibia (shin bone).

Like the other muscles in the anterior compartment of the thigh, sartorius is innervated by the femoral nerve.

There are however known variations in this muscle found in disection. It may originate from the outer end of the inguinal ligament, the notch of the ilium, the ilio-pectineal line or the pubis.

The muscle may be split into two parts, and one part may be inserted into the fascia Iata, the femur, the ligament of the patella or the tendon of the semitendinosus.

The tendon of insertion may end in the fascia lata, the capsule of the knee-joint, or the fascia of the leg.

And the muscle may be absent in some people.

Effects on posture
Due to its location and functions it plays a crucial role in development of knee and lumbar pain.
Activities that make you forcefully push off put a lot of strain on this muscle. Spending a lot of time in Lotus or any cross-legged position (daily meditation in the same position) keeps this muscle in constant contraction. And the muscle can be pulled or strained while jumping and running. Playing sports like hockey, rugby, football or basketball put you at a higher risk of developing a sartorius injury.

If the sartorius is extremely tight it can pull the pelvis forward (down facing arrow) as it will pull the Anterior Superior Iliac Spine down, resulting in a stronger lordosis or the lumbar spine (right pointing arrow).
This could cause lower back pain and pushes the abdomen forward but it can also be a contributing factor to an excessive rounding of the thoracic spine and forward head carriage.

Further down the leg it can create an inward rotation of the leg (knock knees) and cause inner knee pain. Common symptom is pain in the inner knee when lying on the side with the knees together.

If you suffer from any of the above symptoms you might want to jump over to the blog post where we explain what you can do yourself to alleviate your discomfort.Or you could book yourself a Bowen treatment at Valentis Therapy to help your body heal itself.