Which muscle is the primary hip flexor?

Which muscle is the primary hip flexor?

• A. Rectus femoris
• B. Iliopsoas
• C. Sartorius
• D. Tensor fasciae latae

Answer: (B)

The main muscle that flexes the hip is the iliopsoas, a combined muscle made up of the psoas major and the iliacus. It crosses the hip joint and attaches to the lesser trochanter of the femur, giving it a direct and powerful pull to lift the thigh toward the torso. This strong, direct line of action makes it the primary hip flexor, especially in movements like bringing the knee up or rising from a chair. Other muscles crossing the hip can assist with flexion—such as the rectus femoris, which also crosses the hip but is primarily a knee extensor; the sartorius, which can help but is a weaker, multi-joint contributor; and the tensor fasciae latae, which flexes the hip somewhat but mainly stabilizes and assists with abduction and medial rotation.

The main muscle that flexes the hip is the iliopsoas, a combined muscle made up of the psoas major and the iliacus. It crosses the hip joint and attaches to the lesser trochanter of the femur, giving it a direct and powerful pull to lift the thigh toward the torso. This strong, direct line of action makes it the primary hip flexor, especially in movements like bringing the knee up or rising from a chair. Other muscles crossing the hip can assist with flexion—such as the rectus femoris, which also crosses the hip but is primarily a knee extensor; the sartorius, which can help but is a weaker, multi-joint contributor; and the tensor fasciae latae, which flexes the hip somewhat but mainly stabilizes and assists with abduction and medial rotation.