Infraspinatus Muscle, Lateral View

Description

Viewed from the lateral shoulder, the infraspinatus occupies the infraspinous fossa on the posterior surface of the scapula, its broad fibers converging laterally toward a tendon that passes deep to the posterior deltoid. The muscle belly lies inferior to the scapular spine and posterior to the glenohumeral joint, with its insertion directed toward the greater tubercle of the humerus, just lateral to the articular capsule. The proximal humerus, posterior scapular margin, and adjacent rotator cuff interval landmarks sit in close proximity. Clear spatial logic. Clinically, this angle maps directly onto the infraspinatus as an external rotator and dynamic stabilizer that resists anterior translation of the humeral head during abduction. Tendinopathy and partial-thickness tears at the infraspinatus footprint on the greater tubercle are common findings on shoulder MRI and ultrasound, and they often accompany posterosuperior cuff involvement in subacromial impingement patterns. Palpation and dry needling targets also rely on knowing where the muscle belly sits relative to the posterior deltoid and scapular spine. Use this artwork in gross anatomy labs covering the scapulohumeral muscles, in sports medicine and orthopaedic teaching on rotator cuff biomechanics, or in surgical and radiology materials that explain cuff tear location, repair anchor placement, and the posterior approach corridor to the shoulder. It also supports patient-facing education on external rotation weakness and posterior shoulder pain patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.