Long Head of the Triceps, Posterior View

Description

Running from the infraglenoid tubercle of the scapula to the common triceps tendon, the long head of triceps brachii is highlighted in red on the posterior upper limb, descending inferiorly between teres minor superiorly and teres major inferiorly as it approaches the posterior humerus. Lateral to it, the lateral head of triceps emerges from the posterior humeral shaft, while medially the long head helps form the posterior axillary fold with latissimus dorsi and teres major. Superiorly, the posterior deltoid caps the glenohumeral region, with adjacent scapular musculature in grayscale providing landmarks for orientation. Fiber direction is clear. Because the long head crosses both the shoulder and elbow, this posterior perspective gives a clean read on its dual action: elbow extension with a shoulder component (extension and adduction) that becomes obvious when you follow the muscle proximally to the scapula rather than stopping at the humerus. Its borders matter in the operating room and on exams, since the long head defines the medial boundary of the quadrangular space (axillary nerve and posterior circumflex humeral artery) and the lateral boundary of the triangular interval, where the radial nerve and profunda brachii artery pass toward the posterior arm. A critical landmark. This view also supports teaching of posterior approach planning around the triceps and the neurovascular plane near the radial groove in midarm fractures or iatrogenic injury during posterior plating. Suitable for gross anatomy and kinesiology coursework when discussing the triceps heads, posterior shoulder landmarks, and the posterior axilla, and for surgical education materials covering axillary nerve entrapment patterns or radial nerve risk zones in humeral shaft trauma. Anatomical accuracy verified by SciePro's Medical Advisory Board.