Upper Back Muscles Beneath the Skin, Posterior View

Description

Across the posterior upper trunk of an adult male, the trapezius forms a broad superficial sheet from the external occipital protuberance and nuchal ligament down to the thoracic spinous processes, tapering laterally to the acromion and spine of the scapula. Inferior and lateral to it, the latissimus dorsi sweeps superolaterally toward the humerus, while the scapular fossae frame the infraspinatus over the infraspinous fossa and the rhomboid minor and major spanning from the midline to the medial border of the scapula. Along the vertebral column, paraspinal muscle contours (erector spinae region) create paired longitudinal ridges, and the subcutaneous tissue and skin plane remain present as the overlying layer that softens superficial landmarks. Posterior surface anatomy in this region is where scapulothoracic motion becomes readable: the trapezius and rhomboids oppose protraction and upward rotation forces, and their fiber directions help explain common patterns of scapular dyskinesis during overhead activity. Injury to the spinal accessory nerve produces lateral scapular droop and impaired shoulder shrug, while dorsal scapular nerve dysfunction weakens rhomboid-driven retraction, both findings that match what you see on inspection and palpation. A clean posterior perspective also supports teaching the rotator cuff relationship, since infraspinatus sits deep to the posterior deltoid and converges toward the greater tubercle. Rehabilitation teams can pair this artwork with exercise instruction for scapular stabilization, trigger point mapping, and postural retraining, and surgeons can reference it when describing posterior approaches around the scapular spine and medial border. It also fits well in musculoskeletal anatomy courses and in clinical skills texts that teach inspection, palpation, and surface marking of the upper back. Anatomical accuracy verified by SciePro's Medical Advisory Board.