Which action best describes the rectus femoris?

• A. Extends Leg and Flexes Thigh (Kicking Muscle)
• B. Flexes Leg
• C. Abducts Thigh
• D. Extends Thigh

Answer: (A)

Rectus femoris is a biarticular muscle, meaning it crosses both the hip and knee joints. Because of this, it can do two actions: extend the knee and flex the hip (move the thigh forward). Describing it as extending the leg and flexing the thigh captures both of these actions, which is why this option is the best fit. It isn’t an abducter, so it won’t move the thigh away from the midline. It also isn’t primarily a thigh extensor, since the rectus femoris helps flex the thigh at the hip rather than extend it. This dual action makes it a key player in kicking movements, where the thigh flexes at the hip while the knee straightens.