long head of triceps brachii

Key points

• Triceps brachii lies mainly on the back of the upper arm and is the principal muscle that straightens the elbow.
• Its long, lateral and medial heads converge towards an attachment on the olecranon of the ulna.
• The long head crosses both the shoulder and elbow joints, allowing it to contribute to movements at both joints.
• The radial nerve supplies triceps brachii, and the atlas entries associated with this article represent its long head rather than the whole muscle.

Read the guide: Triceps brachii: anatomy, location and function