What is the primary action of the pectineus muscle?

What is the primary action of the pectineus muscle?

• A. Hip Extension
• B. Hip Flexion
• C. Knee Flexion
• D. Ankle Dorsiflexion

Answer: (B)

The pectineus mainly acts to flex the hip. It runs from the superior pubic ramus to the pectineal line of the femur, crossing the hip joint on its anterior-medial aspect. When it contracts, it pulls the femur forward, increasing hip flexion. It can also assist with adduction and slight medial rotation, but its primary action at the hip is flexion. Hip extension would require pulling the thigh backward, which isn’t the pectineus’ role given its anterior position. Knee flexion isn’t driven by this muscle because it doesn’t cross the knee joint to bend the knee. Ankle dorsiflexion involves the muscles crossing the ankle, not the hip, so that action isn’t related.

The pectineus mainly acts to flex the hip. It runs from the superior pubic ramus to the pectineal line of the femur, crossing the hip joint on its anterior-medial aspect. When it contracts, it pulls the femur forward, increasing hip flexion. It can also assist with adduction and slight medial rotation, but its primary action at the hip is flexion.

Hip extension would require pulling the thigh backward, which isn’t the pectineus’ role given its anterior position. Knee flexion isn’t driven by this muscle because it doesn’t cross the knee joint to bend the knee. Ankle dorsiflexion involves the muscles crossing the ankle, not the hip, so that action isn’t related.