Gastrocnemius muscle

Origin: Lateral head arises by a large tendon of the lateral supracondylar tuberosity of the femur. The medial head arises on the medial supracondylar tuberosity of the femur.

Insertion: Via the calcaneal tendon to the tuber calcanei.

Action: Primarily extends the tarsal joint; slight flexion of the stifle joint.

Nerve: Tibialis