Muscle, Subscapularis (M. Subscapularis, Pna, Bna, Jna; M. Infrascapularis)

The subscapularis muscle (lat. musculus subscapula—) is part of the pectoralis major muscle, designed to extend and abduct the arm, lift the arm and the entire upper limb forward.

The pectoralis major muscle starts from the collarbone and attaches to the upper end of the scapula. The pectoralis major muscle is divided into three bundles: clavipectoral, sternocostal and subscapular. They lie one above the other. The muscles are separated by intermuscular septa, one of which is the anterior edge of the muscle, the other is its posterior half. Along this septum there is a connection between the pectoralis major and axillary muscles. The boundary line between the head, abdomen and tail of the middle part of the axillary-brachial nerve passes at the border between the pectoralis major and minor muscles on the side and along the anterior border of the axillary-subscapular groove below.

From the middle of the lateral surface of the pectoralis major muscle