Subscapular System

Abstract

Scapular region is on the superior posterior surface of the trunk and is defined by the muscles that attach to the scapula. These muscles can be divided into extrinsic muscles, which join the axial to the appendicular skeleton (trapezius, latissimus dorsi, levator scapulae, rhomboid minor, and rhomboid major), and intrinsic muscles, which join the scapula to the humerus (deltoid, supraspinatus, infraspinatus, teres minor, teres major, and subscapularis). Scapula is a flat triangular bone which consists of a costal (anterior) surface, a dorsal (posterior) surface, and three borders, superior, medial (vertebral), and lateral (axillary). The lowest point is the inferior angle, defined as the tip of the scapula, while a transverse process, the spine of the scapula, divides the posterior surface in a supraspinous fossa above and a larger infraspinous fossa below. Blood is brought to the scapular region by a network of arteries, which form the scapular anastomosis: muscles medial and superior to the scapula receive blood from the dorsal scapular, transverse cervical, and suprascapular arteries, which are branches of the subclavian artery, and also from the acromial artery, which is a branch of the axillary artery; muscles anterior and lateral to the scapula are supplied by the subscapular and posterior circumflex humeral arteries, which are derived from the axillary artery. The extensive arterial anastomosis at the scapular region provides a collateral circulation, so if one vessel is blocked or damaged, many others can provide blood to the region.