Which muscle originates from the iliac fossa?

Which muscle originates from the iliac fossa?

• A. Iliacus
• B. Psoas major
• C. Rectus femoris
• D. Gluteus medius

Answer: (A)

Iliac fossa origin is a hallmark of the iliacus muscle. The iliacus sits in the iliac fossa on the inner surface of the ilium, and its fibers blend with the tendon of psoas major to form the iliopsoas, which inserts on the lesser trochanter and functions to flex the hip. Psoas major, in contrast, does not start in the iliac fossa—it originates from the bodies and transverse processes of lumbar vertebrae (T12–L5) and then joins with iliacus. Rectus femoris starts at the anterior inferior iliac spine and the acetabular margin, not from the iliac fossa. Gluteus medius arises from the outer surface of the ilium between the anterior and posterior gluteal lines, above the acetabulum, also not from the iliac fossa.

Iliac fossa origin is a hallmark of the iliacus muscle. The iliacus sits in the iliac fossa on the inner surface of the ilium, and its fibers blend with the tendon of psoas major to form the iliopsoas, which inserts on the lesser trochanter and functions to flex the hip.

Psoas major, in contrast, does not start in the iliac fossa—it originates from the bodies and transverse processes of lumbar vertebrae (T12–L5) and then joins with iliacus. Rectus femoris starts at the anterior inferior iliac spine and the acetabular margin, not from the iliac fossa. Gluteus medius arises from the outer surface of the ilium between the anterior and posterior gluteal lines, above the acetabulum, also not from the iliac fossa.