The rectus femoris is part of which muscle group?

• A. Hamstrings
• B. Adductors
• C. Quadriceps femoris
• D. Calf muscles

Answer: (C)

This question tests understanding of muscle group classification in the thigh. The rectus femoris belongs to the quadriceps femoris group, the large front-thigh muscle set that powers knee extension. It’s one of the four muscles in this group (the others are vastus lateralis, vastus medialis, and vastus intermedius). A key point is that the rectus femoris crosses both the hip and knee joints, which lets it contribute to hip flexion as well as knee extension. The other muscle groups listed don’t include the rectus femoris: the hamstrings are at the back of the thigh and primarily extend the hip and flex the knee; the adductors run along the inner thigh and bring the leg toward the midline; the calf muscles are in the lower leg and mainly plantarflex the foot.