Triceps brachii muscle
| Triceps brachii muscle |
|---|
|
| origin |
|
Caput longum : shoulder blade ( tuberculum infraglenoidale ) Caput mediale : medial on the humerus bone Caput laterale : lateral on the humerus bone |
| approach |
| Ulna ( olecranon ) |
| function |
| Extensor of the elbow , adduction of the shoulder joint |
| Innervation |
| Radial nerve |
| Spinal segments |
| C7, C8 |
The triceps brachii muscle ( Latin for "three-headed arm muscle"), often just called the triceps , sits on the back of the upper arm . He pulls the bent forearm backwards until the olecranon (elbow hump) blocks further movement in the elbow joint.
The triceps are made up of three heads of muscles . The long head, the caput longum , arises on the shoulder blade below the joint socket and is involved in the formation of the lateral and medial axillary space . The other two parts ( caput mediale and caput laterale ) arise on the back of the humerus . In the lower third of the upper arm, they unite to form a common end tendon that attaches to the ulna . Some studies indicate that the insertion at the olecranon occurs separately from each other by several tendons of the individual triceps heads. The upper third of the triceps is covered by the deltoid muscle .
In some mammals (e.g. predators ) the muscle has a fourth head, caput intermedium .
function
While the caput mediale and the caput lateral act only on the elbow joint in the sense of a stretching ( extension ), the caput longum can also bring the arm in the shoulder joint closer to the body ( adduction ) and move it backwards ( retroversion ). In quadruped mammals, the caput longum acts as a powerful shoulder joint flexor. The triceps is the antagonist of the biceps brachii muscle .
See also
Individual evidence
- ↑ Michael Madsen, Robert G. Marx, Peter J. Millett, Scott A. Rodeo, John W. Sperling, Russell F. Warren: Surgical Anatomy of the Triceps Brachii Tendon. ( Memento from January 29, 2016 in the Internet Archive )
- ↑ Franz-Viktor Salomon: muscle tissue . In: Anatomy for veterinary medicine . Enke Stuttgart, 2nd ext. Ed. 2008, pp. 147-234. ISBN 978-3-8304-1075-1