The rectus femoris is unique among the quadriceps in crossing both the hip and knee joints. Its dual origin (AIIS and acetabular rim groove) is important in AIIS impingement syndrome in athletes.
| Origin | Straight head: anterior inferior iliac spine (AIIS); Reflected head: groove above the acetabular rim |
|---|---|
| Insertion | Quadriceps tendon — base of patella and via the patellar ligament to the tibial tuberosity |
| Nerve Supply | Femoral nerve (L2, L3, L4) |
| Blood Supply | Lateral circumflex femoral artery — descending branch |
| Actions | Extends the knee; Flexes the hip — the only quadriceps component crossing the hip; The most powerful quadriceps component during simultaneous hip flexion and knee extension (kicking) |
|---|
Rectus femoris avulsion at the AIIS occurs in adolescent kicking athletes — one of the most common apophyseal avulsion injuries. AIIS impingement from a prominent AIIS post-avulsion produces hip flexion pain in extreme positions. Proximal rectus femoris tears (musculotendinous junction) occur in sprinters and kickers, producing anterior thigh pain and a palpable defect.
Palpated as the central anterior thigh muscle during resisted knee extension with hip extended.
Apophyseal avulsion of the rectus femoris straight head from the AIIS in a kicking sport adolescent, managed conservatively with progressive loading rehabilitation.
