The quadriceps femoris (quadriceps extensor, or quads) includes the four remaining muscles on the front of the thigh. It is the great extensor muscle of the leg, forming a large fleshy mass which covers the front and sides of the femur.
It is subdivided into separate portions, which have received distinctive names.
One occupying the middle of the thigh, and connected above with the ilium, is called from its straight course the rectus femoris.
The other three lie in immediate connection with the body of the femur, which they cover from the trochanters to the condyles:
* The portion on the lateral side of the femur is termed the vastus lateralis.
* The portion covering the medial side is termed the vastus medialis.