Triceps brachii (Musculus triceps brachii)
Educational content only — not medical advice.
Anatomy
The sole muscle of the posterior arm compartment: three heads converging into one tendon on the olecranon. It is the only extensor of the elbow, and its long head crosses the shoulder to help stabilize it.
Origin & insertion
Origin: long head from the infraglenoid tubercle; lateral and medial heads from the humeral shaft. Insertion: olecranon of the ulna and its aponeurosis.
Action
Extends the elbow joint.
Innervation
Radial nerve (C6–C8)
Clinical notes
Tendon avulsion from the olecranon is rare but abolishes extension completely; resisted elbow extension tests the radial nerve.
Related structures
Educational references
FAQ
What is the role of the Triceps brachii?
The sole muscle of the posterior arm compartment: three heads converging into one tendon on the olecranon. It is the only extensor of the elbow, and its long head crosses the shoulder to help stabilize it.
Why is the Triceps brachii clinically important?
Tendon avulsion from the olecranon is rare but abolishes extension completely; resisted elbow extension tests the radial nerve.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details