What is the origin of the rectus femoris?

• A. AIIS
• B. ASIS
• C. Greater trochanter
• D. Iliac Crest

Answer: (A)

Rectus femoris is one of the quadriceps and is unique in crossing both the hip and knee joints, so its proximal attachment needs to sit on a pelvic structure that anchors a hip-flexing muscle. The primary origin is the anterior inferior iliac spine. This placement lets the muscle contribute to hip flexion while also extending the knee. There is sometimes a second proximal head from the acetabular rim (a reflected head), but the AIIS is the main origin most consistently cited.

The ASIS serves as the origin for other structures like the sartorius, the greater trochanter is where the hip abductors and rotators attach, and the iliac crest is a site for other muscle origins; none of these are the primary origin of rectus femoris.