Long Head of the Triceps Brachii Beneath the Skin, Medial View

Description

Medially along the posterior arm, the long head of triceps brachii is presented as a fusiform belly arising from the infraglenoid tubercle of the scapula and descending inferiorly to join the triceps tendon toward the olecranon of the ulna. Superficial skin has been removed, so the deep fascia (brachial fascia) can be appreciated as it invests the muscle and defines its contour. Proximally, the long head lies medial to the lateral head and posterior to the humerus, forming the medial boundary of the quadrangular space and the lateral boundary of the triangular interval. Relationship is the lesson. Clinically, this medial perspective helps orient surgeons and trainees to the posterior shoulder and arm corridors where the axillary nerve and posterior circumflex humeral artery traverse the quadrangular space, and where the radial nerve with the profunda brachii artery pass through the triangular interval before entering the spiral groove. Distal to the muscle belly, continuity into the common triceps tendon matters when discussing partial versus complete triceps tears near the olecranon and the exam finding of weakness in elbow extension. The fascia is not decoration, it is a plane. Use this artwork in gross anatomy lab manuals, orthopedic and sports medicine teaching on posterior shoulder approaches, and rehabilitation materials that explain elbow extensor mechanics and palpable landmarks along the posteromedial arm. It also suits surgical anatomy figures for nerve entrapment, iatrogenic risk zones, and triceps tendon repair orientation. Anatomical accuracy verified by SciePro's Medical Advisory Board.