vastus intermedius /vas″təs/ [L, vastus, enormous, inter, between, mediare, to divide] , one of the four muscles of the quadriceps femoris group, situated in the center of the thigh under the rectus femoris. It arises from the front and lateral surfaces of the femur and the medial and lateral intermuscular septa. Its fibers end in a superficial aponeurosis that forms the deep part of the quadriceps femoris tendon, inserted under the patella and onto the tibial tuberosity. It functions with the other three muscles of the quadriceps to extend the leg. Its deepest fibers are called articularis genus. Also called crureus. Compare rectus femoris, vastus lateralis, vastus medialis. See also quadriceps femoris.
