Popliteus muscle the ankle. The gastrocnemius muscle acts on both joints. It originates from the lateral surface of the lateral condyle of femur by a rounded tendon, the fibers pass downward and medially and give insertion to the posterior surface of tibia, above the soleal line. The muscle arises within the capsule of knee joint and its tendon separates the lateral meniscus from the lateral ligament of the joint. Nerve supply is via the tibial nerve from spinal roots L5 and S1. There is sometimes an additional head from the sesamoid bone in the lateral (outer) head of the gastrocnemius muscle. Rarely
Subscapularis muscle Subscapularis muscle The subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint. It arises from its medial two-thirds and from the lower two-thirds of the groove on the axillary border (subscapular fossa) of the scapula. Some fibers arise from tendinous laminae, which intersect the muscle and are attached to ridges on the bone; others from an aponeurosis, which separates the muscle from the teres major and the long head of the triceps brachii. The fibers pass laterally and coalesce into