The sartorius is the longest muscle in the body, crossing both the hip and knee as a two-joint muscle. It produces the tailor's position (sitting cross-legged) by combining hip flexion, abduction, and external rotation with knee flexion. Its course from the ASIS to the medial tibia passes lateral to medial — it is used as the anterior leaf of the subsartorial (adductor) canal flap, providing tissue for medial knee coverage.
| Origin | Anterior superior iliac spine (ASIS) |
|---|---|
| Insertion | Upper medial tibia — pes anserinus (most anterior component, immediately anterior to the gracilis) |
| Nerve Supply | Femoral nerve (L2, L3) |
| Blood Supply | Sartorius branch of the femoral artery |
| Actions | Hip flexion; Hip abduction; Hip external rotation; Knee flexion; Internal tibial rotation when the knee is flexed |
|---|
The sartorius tendon is the most anterior and superficial component of the pes anserinus insertion on the medial tibia. ASIS avulsion fractures in skeletally immature athletes involve the sartorius origin — the ASIS is the most commonly avulsed pelvic apophysis. The sartorius is a useful landmark at the femoral triangle lateral border identifying the interval between it and the tensor fasciae latae.
The sartorius is palpable from the ASIS diagonally across the anterior thigh during resisted hip flexion and external rotation, and as a medial knee tendon at the pes anserinus during resisted knee flexion.
Sartorius origin avulsion at the ASIS in adolescent sprinters managed conservatively for non-displaced fractures and surgically for greater than 2 cm displacement.
