Muscle
Triceps brachii
Chief elbow extensor
High-yield
Only extensor of the elbow; radial nerve. Triceps reflex tests C7. Long head separates quadrangular and triangular spaces.
Overview
The three-headed muscle of the posterior arm that is the main extensor of the elbow. Its long head crosses the shoulder.
Reference facts
- Origin
- Long head: infraglenoid tubercle of scapula. Lateral head: posterior humerus above the radial groove. Medial head: posterior humerus below the radial groove
- Insertion
- Olecranon process of the ulna
- Action
- Extends the forearm at the elbow; long head extends and adducts the arm
- Innervation
- Radial nerve (C6, C7, C8)
- Blood supply
- Deep brachial (profunda brachii) artery
Frequently asked questions
What does the triceps brachii do?
The triceps brachii extends the forearm at the elbow; long head extends and adducts the arm.
What nerve innervates the triceps brachii?
The triceps brachii is innervated by the radial nerve (C6, C7, C8).
Where does the triceps brachii attach?
Origin: Long head: infraglenoid tubercle of scapula. Lateral head: posterior humerus above the radial groove. Medial head: posterior humerus below the radial groove. Insertion: Olecranon process of the ulna.
What is the blood supply of the triceps brachii?
The triceps brachii is supplied by the deep brachial (profunda brachii) artery.