Origin Anterior part of the popliteal groove on lateral surface of lateral femoral condyle Insertion Posterior surface of tibia in a fan-like fashion, just superior to the popliteal line Action Internally rotates tibia relative to femur and unlocks knee during knee flexion initiation Innervation Tibial nerve (L4, L5, S1) (L4, L5, S1) Arterial Supply Medial inferior genicular branch of popliteal artery and muscular branch of posterior tibial artery