Infraspinatus Muscle Under the Skin

Description

Running across the posterior shoulder girdle, the deltoid cap is emphasized bilaterally while the overlying skin remains in place, letting you track the contours of the scapula and the underlying rotator cuff. Deep to the posterior deltoid, the infraspinatus occupies the infraspinous fossa inferior to the scapular spine, with fibers converging laterally toward the greater tubercle of the humerus. Teres minor sits along the lateral border of the scapula, just inferior to infraspinatus and superior to teres major, while trapezius frames the superior medial back near the midline spinous processes. Midline symmetry reads clearly. Posterior shoulder pain often gets mislabeled as generic strain, and this view helps separate deltoid bulk from the flatter infraspinatus belly that drives external rotation at the glenohumeral joint. Pay attention to the lateral scapular border and the region of the spinoglenoid notch, where the suprascapular nerve can be compressed by a ganglion cyst, producing selective infraspinatus atrophy with relative supraspinatus sparing. A clear landmark. The lateral fiber direction also supports teaching of rotator cuff force couples, since infraspinatus and teres minor counterbalance subscapularis to center the humeral head during abduction. Use this artwork for gross anatomy labs covering the posterior scapular region, kinesiology modules on shoulder external rotation, and orthopedics or sports medicine materials on rotator cuff tendinopathy and postoperative rehabilitation after arthroscopic repair. It also fits patient-facing explanations of rotator cuff tears when you want skin-surface orientation without losing the relationship to scapular landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.