Triceps brachii · lateral head

Lateral is an anatomical direction

The lateral head is a humeral component of triceps brachii. It is not the long head viewed from a different angle.

Camera rotation can swap the apparent left and right sides of the screen. Use the structure name and neighboring bones to identify the head instead of relying on its screen position.

Sources: Loyola anatomy

A posterior humeral origin

Its origin lies on the upper posterior humerus. The distal triceps attachment is on the ulnar olecranon, rather than the radius.

Compare this with the medial head’s lower, deeper humeral origin. The geometry provides surface shapes, not a drawn border between their attachment footprints.

Sources: Loyola anatomy

Contributing to elbow extension

The lateral head contributes to straightening the elbow. Unlike the long head, its humeral origin does not give it the same shoulder-spanning course.

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

The size of a rendered mesh is not a measurement of strength. This viewer does not rank the heads or prescribe exercises for one of them.

Sources: Arm anatomy tables

Radial nerve and deep brachial supply

Motor supply comes through radial-nerve branches. The deep brachial artery contributes to the muscle’s blood supply.

Nerves and vessels are not loaded in this subset, so the text describes connections you cannot select in the viewer.

Sources: Arm anatomy tables

Read the model

Explore triceps brachii · lateral head in 3D

1. Inspect the lateral head alone. Use Back and Oblique to inspect its outline without the other heads overlapping it.
2. Find the humeral context. Choose Show context, select the lateral head and enable Fade others. Switch to Humerus to see the bone around which the heads are arranged.
3. Compare lateral with medial. Alternate the two names in the structure list. For a closer look, use Isolate and Focus selection. Open the other head’s title to compare its guide.

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.

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