The sartorius muscle is a long, slim, superficially running muscle, formally belonging to the extensors of the thigh. The sartorius muscle moves both the hip and knee joint.
Even though it is located in the anterior compartment of the thigh, it should not be confused as an extensor of the thigh.
It serves a number of functions in the lower limb, as it works on both the hip and knee joints.
|Origin||Anterior superior iliac spine (ASIS)|
|Insertion||Medial surface of proximal tibia (via pes anserinus)|
|Innervation||Femoral nerve (L2-L4)|
Hip joint: thigh flexion, thigh abduction, thigh external rotation;
Knee joint: leg flexion, leg internal rotation
This article will discuss the anatomy of the sartorius muscle.
Anatomy and supply
It originates from the anterior superior iliac spine of the pelvic bone and runs spirally towards the knee region. There it inserts at the pes anserinus medially from the tibial tuberosity. In its entire course the muscle is covered by a fascial duplication of the fascia lata. The innervation is supplied by the femoral nerve (L2-L4).
Topographically the sartorius muscle forms the lateral border of the femoral triangle (Scarpa’s triangle) where the large vessels of the thigh pass through. For this reason the muscle serves as a leading structure when surgically accessing the femoral artery.
The sartorius muscle is a two-joint muscle and moves both the hip and knee joint. Even though anatomically it ranks among the extensors of the thigh, because it is located in the anterior (extensor) compartment of the thigh, its contraction truly causes a flexion of the hip joint. IIt is also involved in the abduction and outward rotation of the hip joint.
In the knee joint, it forces flexion and inward rotation. The flexion movement is the result of the tendon inserting at the knee joint behind the flexion-extension axis. When all five movements are executed simultaneously the legs would cross like in a tailor seat. Therefore, the “tailor’s muscle” is most easily palpable in this position.
The pes anserine bursa located at the insertion of the sartorius muscle can become inflammed (pes anserine bursitis) when chronically overstrained (e.g. when jogging or breaststroking).
Common symptoms are pain, swelling and a functional impairment of the three muscles inserting at the pes anserinus (sartorius, semitendinosus and gracilis muscle). If the inflammation is overseen or poorly treated (rest, cooling, pain medication, local corticoid injection if necessary) the bursitis often becomes chronic.