Posterior Perspective of the Infraspinatus Muscle

Description

Posterior surface anatomy of the shoulder girdle is centered on the scapula, where the infraspinatus occupies the infraspinous fossa inferior to the scapular spine and courses laterally toward its tendon on the greater tubercle of the humerus. Along its superior margin it approaches the spine and supraspinous region, while inferiorly it is bounded by the lateral border of the scapula near the teres minor and, more caudally, teres major. Laterally, the posterior deltoid caps the glenohumeral joint and overlaps the rotator cuff insertional area, providing a clear reference for the relationship between superficial shoulder contour and the deeper cuff musculature. Adjacent posterior trunk muscles, including trapezius superiorly, latissimus dorsi inferolaterally, and the erector spinae columns medially, frame the scapulothoracic region. External rotation strength lives here. Infraspinatus dysfunction is a common contributor to posterior shoulder pain and weakness, and its tendon is frequently involved in rotator cuff tendinopathy or full thickness tears that present with loss of resisted external rotation and a positive external rotation lag sign. The posterior view also supports teaching of suprascapular nerve anatomy, since compression at the spinoglenoid notch can selectively denervate the infraspinatus while sparing supraspinatus, a pattern seen with paralabral cysts and overhead athletes. Use this artwork for upper limb anatomy and kinesiology modules, rotator cuff chapters in orthopedic and sports medicine texts, and physiotherapy resources on scapulohumeral rhythm and cuff testing. It also fits procedural education when explaining palpation landmarks for posterior shoulder examination and guiding safe needle trajectory away from the suprascapular neurovascular bundle. Anatomical accuracy verified by SciePro's Medical Advisory Board.