Upper limb

Triceps Brachii, Lateral Head

Musculus triceps brachii (caput laterale)

Origin

Posterior surface of the humerus, proximal to the radial groove

Insertion

Olecranon of the ulna (common triceps tendon)

Function

Extends the elbow

Innervation

Radial nerve, C7–C8

Movement & chain

The most powerful of the three triceps heads during fast, forceful elbow extension such as a punching or pushing movement.

Palpation

Palpable on the lateral posterior upper arm, between the long and medial heads, during resisted elbow extension.

Clinical

Along with the other heads, involved in triceps tendon ruptures, which often occur with eccentric loading (for example bench press).

Segmental innervation

Radial nerve, C7–C8.

In clinical practice

The lateral head is a commonly used site for intramuscular injections in the upper arm.

Region in the model

Upper limb