A Lateral View of the Infraspinatus Muscle in a Male

Description

Seen from a lateral shoulder angle, the infraspinatus occupies the infraspinous fossa on the posterior surface of the scapula, lying inferior to the scapular spine and posterior to the glenohumeral joint. Its muscle fibers converge laterally toward a tendon that passes deep to the posterior deltoid to insert on the middle facet of the greater tubercle of the humerus. Superiorly, the infraspinatus abuts the spine and supraspinous fossa, while inferiorly it blends toward the lateral border near the teres minor, with the humeral head positioned anterolateral to the scapular body. External rotation lives here. This lateral perspective clarifies how the infraspinatus functions as a primary external rotator and a dynamic stabilizer of the humeral head against the glenoid, a relationship that becomes clinically obvious in rotator cuff tendinopathy and posterosuperior cuff tears where external rotation strength and endurance drop. It also supports teaching around the posterior shoulder approach, where splitting deltoid fibers exposes the interval leading toward the rotator cuff without confusing the infraspinatus with the more inferior teres minor. Use this artwork for anatomy and kinesiology instruction on the rotator cuff, for orthopedic and sports medicine chapters discussing cuff pathology, and for patient education materials explaining posterior shoulder pain and weakness during external rotation. Anatomical accuracy verified by SciePro's Medical Advisory Board.