The Anatomical Structure and Location of the Upper Subscapular Nerve of a Human Male

Description

Arising from the posterior cord of the brachial plexus (C5 to C6), the upper subscapular nerve is traced in the axillary region as it courses posterolaterally toward the anterior (costal) surface of the scapula. Its short branch runs inferior to the clavicle and deep to the proximal humerus, heading directly to the superior portion of subscapularis near the subscapular fossa. Adjacent landmarks logically included in this thoracic and shoulder-girdle model include the ribs and costovertebral joints posteriorly, the upper sternum anteriorly, and the scapula lying posterolateral to the rib cage. It is a small nerve. Clean identification of the upper subscapular nerve matters when teaching posterior cord branching and when sorting shoulder weakness by pattern rather than by muscle name alone. Denervation of the superior subscapularis fibers can contribute to loss of internal rotation strength and reduced anterior glenohumeral stability, a point that becomes practical during evaluation of brachial plexus traction injuries or iatrogenic injury around the axilla. This relationship also frames why surgical exposure near the anterior scapula, including approaches that retract subscapularis during open stabilization or shoulder arthroplasty, demands awareness of the nerve’s short, direct course. Educators commonly pair this figure with modules on brachial plexus anatomy, scapulothoracic relationships, and rotator cuff innervation in gross anatomy, kinesiology, or orthopedic residency teaching. It also fits well in operative anatomy sections for textbooks and in patient-facing materials explaining post-traumatic plexopathy patterns after shoulder dislocation or high-energy traction. Anatomical accuracy verified by SciePro's Medical Advisory Board.