The quadriceps femoris is the large extensor muscle of the anterior thigh. Four smaller muscles make up the quadriceps femoris; they are the rectus femoris, the vastus lateralis, the vastus medialis, and the vastus intermedius, forming a large dense mass covering the front and sides of the femur. Tendons of these four muscles that constitute the quadriceps get together at the distal part of the thigh, forming a single strong tendon that embeds the patella and inserts onto the tibial tuberosity. The quadriceps functions to extend the leg as it is very important in walking, running, jumping and squatting. Since the rectus femoris attaches to the ilium, it is also a flexor of the hip. The quadriceps femoris is supplied by the femoral artery and innervated by the femoral nerve.