Considered the knee’s great extensor muscle, the Quadricepts Femoris, named for its four heads, is most often referred to as the quadricepts, or even better, quads. The quads are a big group of muscles situated on the front of the thigh, lending the femur a cushy covering. Making up the group are the Rectus Femoris, which sits at the centre of the thigh and blankets the other three muscles, Vastus Lateralis which resides on the outer surface of the thigh, Vastus medialis which is on the femur’s medial side, and Vastus Intermedius which rests in between the two Vastus muscles.
A critical muscle in all knee-related actions such as jumping, walking, running, squatting, and kneeling, Quadricepts Femoris is an extremely strong knee extensor, and with an attachment to the ilium, the quads can also flex the hip, give stabilization to the patella, and smoothen the action of the knee while moving. The quads are innervated by (receive their control from) a branch of the femoral nerve.