Quadriceps Health Dictionary

(More accurately quadriceps femoris) – the large, four-headed muscle occupying the front and sides of the thigh, which straightens the leg at the knee-joint and maintains the body in an upright position. It comprises the rectus femoris, vastus lateralis, vastus intermedius and vastus medialis.

n. one of the great extensor muscles of the legs. It is situated in the thigh and is subdivided into four distinct portions: the rectus femoris (which also flexes the thigh), vastus lateralis, vastus medialis, and vastus intermedius (see illustration).