infraglenoid

Infraglenoid is an anatomical term used to describe structures located below the glenoid fossa of the scapula. The most prominent infraglenoid structure is the infraglenoid tubercle, a small bony prominence on the lateral border of the scapula just inferior to the glenoid cavity.

Anatomy and relations: The infraglenoid tubercle lies along the lateral border of the scapula, near the inferior margin of the glenoid cavity. It is the origin of the long head of the triceps brachii. The long head runs with the other heads of the triceps down the posterior arm and is innervated by the radial nerve, with vascular supply from branches of the profunda brachii artery.

Function: The infraglenoid region provides attachment for the long head of the triceps brachii, which contributes to extension of the elbow and also assists with shoulder stabilization in certain positions. The coordination of all three heads enables powerful elbow extension and, with the long head, contributes to shoulder extension and adduction to some extent.

Clinical relevance: Fractures or avulsions involving the infraglenoid tubercle are uncommon but can occur with shoulder girdle injuries, scapular fractures, or dislocations. Such injuries may affect the function of the long head of the triceps, potentially weakening elbow extension or altering shoulder mechanics. Diagnosis is typically via imaging, and treatment depends on the injury pattern and should consider the radial nerve and vascular structures in the area.

See also: scapula anatomy, glenoid cavity, triceps brachii, radial nerve.