Infraspinatus Muscle

Description

Positioned in the infraspinous fossa of the scapula, the infraspinatus muscle occupies the broad posterior surface inferior to the scapular spine, its fibers running superolaterally toward a stout tendon that passes deep to the posterior deltoid to reach the greater tubercle of the humerus. Superiorly, trapezius contours the posterior neck and shoulder girdle, while rhomboid major and minor lie deep and medial along the vertebral border of the scapula. Along the lateral border, the infraspinatus sits adjacent to teres minor superiorly and teres major inferiorly, with latissimus dorsi sweeping inferolaterally toward the posterior axillary fold. Other posterior compartment groups are shown in context, including triceps brachii in the arm and the extensor mass in the forearm. Clear landmarks. External rotation strength and dynamic glenohumeral stability hinge on this rotator cuff component, so a focused posterior view helps you teach how its tendon blends with the capsule and how its line of pull compresses the humeral head against the glenoid during elevation. Clinically, infraspinatus tendinopathy and partial thickness tears often coexist with subacromial impingement, and selective atrophy can point to suprascapular nerve entrapment at the spinoglenoid notch, a pattern commonly discussed alongside MRI findings and overhead athlete mechanics. Distinguishing infraspinatus from teres minor matters in exam and imaging, because isolated weakness of external rotation at 0 degrees abduction can shift differential diagnosis. Use this plate in upper limb anatomy labs, kinesiology and biomechanics lectures on shoulder rotation, and orthopedics or sports medicine materials covering rotator cuff pathology, posterior shoulder approaches, and postoperative rehab counseling. It also supports atlases and patient education handouts that need an accurate posterior map of scapular musculature in a female body habitus. Anatomical accuracy verified by SciePro's Medical Advisory Board.