Name

# Triceps Brachii

Pronunciation

(TRI-seps BRA-ke-I)

Origin/Proximal Attachment

Long Head: infraglenoid tubercle of the scapula Lateral Head: upper 1/2 of the posterior surface of the shaft of the humerus. Medial Head: posterior shaft of the humerus, distal to radial groove & both the medial

Insertion/Distal Attachment

Posterior surface of the olecranon process of the ulna, deep fascia of the antebrachium

Action/Relevance

All Heads: extends the forearm at the elbowLong Head: Adducts the armLong Head: Extends the shoulder (from a flexed position)

Innervation

Radial nerve (C7,8)

Notes

The triceps brachii muscle is a large three-headed skeletal muscle found in humans. It runs along the back of the upper arm and serving to extend the forearm, hence it is an extensor muscle.

The triceps brachii muscle is often simply called the triceps. However, the term triceps (Latin for "three heads") can mean any skeletal muscle having three origins.

The three heads are called: the Long Head, the Lateral Head and the the Medial Head

The Triceps account for 2/3 of the arm's mass and people who exercise the arms with weights often neglect this group of muscles in favour of the biceps brachii.