One of the four muscles of the quadriceps femoris group, situated in the center of the thigh under the rectus femoris.

It comes up from the front and lateral surfaces of the femur (main bone in the human thigh) and the medial and lateral intermuscular septa (thin partition or membrane).

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 (the small skeletal muscle located anteriorly on the thigh just above the knee).