key term - Triceps brachii

Definition

The triceps brachii is a major muscle on the back of the upper arm responsible for extending the elbow. It comprises three heads (long, medial, and lateral) that converge to attach to the ulna, one of the forearm bones.

Related terms

Elbow Extension: The action of increasing the angle between the forearm and upper arm, primarily performed by the triceps brachii.

Biceps Brachii:

A muscle located on the front of the upper arm opposite to the triceps, mainly involved in bending (flexing) the elbow.

Ulna:

One of two bones forming the forearm, where the triceps brachii attaches at its lower end to allow for elbow extension