n. any of three muscles (vastus intermedius, vastus lateralis, and vastus medialis) that form part of the *quadriceps muscle of the thigh.
(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.... quadriceps
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