Vastus Intermedius

Musculus vastus intermedius

Lower Body LegsQuadricepsAnterior Compartment of the ThighAnterior Chain

Lying deep to the rectus femoris and between the two vasti, the vastus intermedius is a pure knee extensor that adds overall quad thickness. Because it sits beneath the rectus femoris it cannot be isolated visually, but it contributes substantially to extension torque across all knee angles and is trained by any heavy squat or leg-press work.

Actions

Knee extension

Origin

Anterior and lateral surfaces of the proximal two-thirds to three-fourths of the femoral shaft and the lateral lip of the linea aspera.

Insertion

Deep part of the quadriceps tendon and base/lateral margin of the patella, continuing to the tibial tuberosity via the patellar ligament.

Innervation

Femoral nerve (L2–L4).

Blood supply

Lateral circumflex femoral artery (descending branch) and deep femoral (profunda femoris) artery.

Wikipedia ↗

quadslegsknee-extensiondeep-quadsquat