Infraspinatus Beneath the Skin, Lateral View

Description

Seen from the lateral aspect of the male upper trunk, the infraspinatus muscle occupies the infraspinous fossa on the posterior surface of the scapula, lying inferior to the scapular spine and deep to the posterior fibers of the deltoid. Its fibers converge laterally toward the glenohumeral joint, passing posterior to the humeral head to form the infraspinatus tendon as it inserts on the middle facet of the greater tubercle. Adjacent relationships you would expect in this projection include the teres minor inferiorly along the lateral border of the scapula and the posterior contour of the acromion arching superior to the humeral head. Clear landmarks. Functionally, the infraspinatus is the primary external rotator of the shoulder and a posterior stabilizer of the humeral head, so its position relative to the posterior joint capsule and the greater tubercle matters when you are teaching cuff mechanics or interpreting pain patterns. Posterior-superior cuff tendinopathy and partial-thickness tears often present with weakness in resisted external rotation and nocturnal shoulder pain, and this lateral view makes it easier to connect symptoms to the tendon’s course under the deltoid and toward the greater tubercle. For arthroscopic planning, the anatomy also aligns with standard posterior portal placement and helps explain why posterior cuff pathology can be missed if you only think in anterior terms. Use this artwork in gross anatomy and kinesiology modules covering the rotator cuff, in orthopedic and sports medicine teaching decks discussing external rotation testing and cuff tear patterns, or in patient-facing education for shoulder rehabilitation exercises that target the infraspinatus without over-recruiting the deltoid. It also supports clinical publishing where a semi-transparent skin overlay clarifies deep muscle-to-bone relationships while preserving surface anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.