Triceps brachii · long head

The scapular head of triceps

The long head is one of three heads of triceps brachii. Its scapular origin distinguishes it from the humeral origins of the lateral and medial heads.

All three are separate selectable meshes here, but they belong to one muscle. A separate page is a way to study a head, not a claim that it is an independent muscle.

Sources: Loyola anatomy

From below the socket to the elbow

The long head begins at the infraglenoid tubercle of the scapula, below the shoulder socket. Distally, the triceps attachment reaches the olecranon of the ulna.

Both bones are loaded on this page. The tubercle and tendon footprint are not separate clickable structures; selecting Scapula or Ulna highlights the whole bone.

Sources: Loyola anatomy

An elbow action and a shoulder role

Alongside elbow extension, the long head contributes to shoulder extension and adduction. Its two-joint course separates it from the humeral heads.

Rotating the model changes the viewpoint only. It does not move the joints, shorten muscle fibers or calculate how much force each head contributes.

Sources: Arm anatomy tables

Usual supply and reported variation

Radial-nerve supply is the standard description. Research on the long head has also reported axillary or posterior-cord contributions, with differing findings between studies; no single prevalence is assumed here.

Deep brachial arterial branches contribute to triceps blood supply. Nerves and vessels are absent from the scene, so the model cannot resolve an individual branching pattern.

Sources: Innervation study (2018) · Variation study (2017) · Arm anatomy tables

Read the model

Explore triceps brachii · long head in 3D

1. Start with the posterior view. Choose Back, then drag the isolated long head to inspect its shape. Use its full name to distinguish it from the long head of biceps.
2. Restore the shoulder bones. Choose Show context and select the long head again. Enable Fade others, then alternate between Scapula and the selected head to compare their positions.
3. Compare the humeral heads. Select the lateral or medial triceps head in the list. Open its title to continue with a guide to that head’s different origin.

Sources and editorial status

This guide uses independently written explanations with links to the evidence behind them. Source checking and specialist anatomical review are separate steps; the latter is still pending.

1. Loyola University Chicago — LUMEN, Triceps

   Head-specific origins, ulnar attachment and elbow action. No source illustrations reproduced.

2. Texas Tech University Health Sciences Center El Paso — Axilla, Posterior Shoulder, & Arm

   Triceps row: head origins, elbow and long-head shoulder actions, radial nerve and deep brachial arterial supply.

3. Wade, McDowell & Ziermann — Innervation of the Long Head of the Triceps Brachii in Humans—A Fresh Look (2018)

   Abstract: 27 triceps from 15 cadavers, all with radial supply in that sample; discussion of differing reports. No prevalence generalized.

4. Erhardt & Futterman — Variations in the Innervation of the Long Head of the Triceps Brachii: A Cadaveric Investigation (2017)

   Abstract: cadaveric study reporting radial, axillary and dual patterns. Read alongside the 2018 study; not a patient-specific nerve map.

3D geometry and its separate license are credited beneath the viewer. References do not imply endorsement of this site.