Long Head of the Triceps Brachii, Posterior View

Description

Posteriorly, the long head of triceps brachii is presented as a fusiform muscle belly arising from the infraglenoid tubercle of the scapula and descending along the medial aspect of the posterior arm. Lateral to it, the lateral head of triceps and the posterior contour of the humeral shaft frame the muscle as it converges distally toward the common triceps tendon inserting on the olecranon of the ulna. Superiorly at the posterior axillary fold, the long head lies adjacent to teres major, with the interval between them forming part of the boundaries of the quadrangular space and the triangular interval. This relationship matters when you are teaching axillary and posterior arm anatomy, because the long head of the triceps is a working landmark for neurovascular passage. The radial nerve and profunda brachii artery traverse the triangular interval inferior to teres major and lateral to the long head, a corridor implicated in compression syndromes and in fracture patterns around the midshaft humerus where nerve injury produces wrist drop. Surgeons also use the long head as a reference during posterior approaches to the humerus and when orienting to the posterior circumflex humeral vessels near the quadrangular space. Clear boundaries. Less guesswork. Use this artwork in gross anatomy and musculoskeletal courses to reinforce triceps compartment anatomy, axillary spaces, and surface landmarks of the posterior axillary fold in the male. It also reads well in orthopedic and sports medicine materials discussing radial nerve palsy, posterior humeral exposure, or triceps-related posterior shoulder pain patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.