Summary Vastus medialis Origin Inferior portion of intertrochanteric line, spiral line, medial lip of linea aspera, superior part of medial supracondylar ridge of femur, and medial intermuscular septum Insertion Medial base and border of patella; also forms the medial patellar retinaculum and medial side of quadriceps femoris tendon Action Extends the knee Innervation Muscular branches of femoral nerve (L2, L3, L4) Arterial Supply Femoral artery, profunda femoris artery, and superior medial genicular branch of popliteal artery