Anatomical Location of the Infraspinatus

Description

Posterior shoulder anatomy is centered on the infraspinatus occupying the infraspinous fossa of the scapula, its broad fibers running laterally and slightly superiorly to converge on a thick tendon. The tendon courses deep to the posterior deltoid and inserts on the middle facet of the greater tubercle of the humerus, just inferior to the supraspinatus insertion and superior to teres minor. Medially, the muscle originates from the scapular spine and infraspinous fossa; laterally it approaches the glenohumeral joint capsule, where its cuff fibers blend with the capsule near the posterior aspect of the greater tubercle. External rotation lives here. Because the infraspinatus forms the dominant posterior component of the rotator cuff, this view helps you correlate the line of pull with clinical tests such as resisted external rotation and the external rotation lag sign used to screen for posterosuperior cuff tears. The course of the suprascapular nerve and vessels at the spinoglenoid notch sits at the functional doorstep of the infraspinatus, making this muscle the one that denervates in isolated spinoglenoid notch ganglion compression seen in overhead athletes. Use this illustration for upper limb and back dissection guides, rotator cuff teaching in orthopedic and sports medicine modules, and physical therapy resources that differentiate infraspinatus weakness from deltoid or teres minor compensation. It also suits surgical education for posterior shoulder arthroscopy portals and for explaining pain patterns in posterior cuff tendinopathy in women. Anatomical accuracy verified by SciePro's Medical Advisory Board.