The iliopsoas is composed of which two muscles?

• A. Iliacus and Psoas major
• B. Gluteus maximus and gluteus medius
• C. Sartorius and Tensor fasciae latae
• D. Rectus femoris and vastus lateralis

Answer: (A)

The key idea here is identifying the two muscles that blend to form the iliopsoas. The iliopsoas is made up of the iliacus and the psoas major. The iliacus originates from the iliac fossa of the pelvis, while the psoas major comes from the lumbar spine. They converge to insert on the lesser trochanter of the femur, working together as the primary hip flexor to lift the thigh or bend the trunk toward the thigh.

Other muscles listed are not part of this combined group: the gluteus maximus and gluteus medius are mainly hip extensors and stabilizers; the sartorius and tensor fasciae latae assist with hip flexion among other actions but are separate muscles; and the rectus femoris with vastus lateralis are part of the quadriceps used to extend the knee (rectus femoris also crosses the hip but does not form the iliopsoas).