Knee extension

Vastus Intermedius is one of four quadricep muscles, located deep in the thigh underneath the Rectus Femoris muscle.

Vastus Lateralis is the most lateral (outer) of the four quadriceps knee muscles and is felt on the outside top of the thigh.

Vastus Medialis is the quadriceps muscle on the inside of the knee. The portion of the muscle just above the knee is known as VMO