The vastus intermedius muscle is one of the four heads of the quadriceps femoris. It lies on the anterior aspect of thigh, between the vastus lateralis and vastus medialis. It is completely covered by the rectus femoris muscle.
The vastus intermedius muscle arises from the intertrochanteric line of head of femur. Then it travels downwards along the femur getting narrower as it goes. When it has reached the middle portion of thigh, it becomes a wide tendon, which fuses with the tendon of the rectus femoris to form the common tendon of the quadriceps femoris muscle.
Action
Extension of leg at the knee joint.
Innervation
This vastus intermedius muscle is innervated by nerve fibers arising from the femoral nerve (L2-L4).
Blood Supply
Like the other muscles of quadriceps, it receives oxygenated blood from the lateral circumflex and profunda femoris artery.
Below, two pictures of vastus intermedius; the first one with the vastus lateralis and the vastus medialis. The other without these muscles.
