Lateral head of triceps brachii
Caput laterale musculi tricipitis brachii
- Related terms: Lateral head; Triceps brachii: Lateral head; Triceps brachii : Lateral head; Triceps brachii - Lateral head
Definition
Lateral head of triceps brachii | |||
Origin | Posterior humerus, above the radial groove | ||
Insertion | Olecranon process of the ulna | ||
Artery | Profunda brachii artery | ||
Innervation | Radial nerve | ||
Action | Extends the forearm. | ||
Antagonist | Biceps brachii and brachialis muscles | ||
The lateral head of triceps brachii originates from the posterior surface of the shaft of the humerus, superior to the radial groove. It also receives additional fibers from the lateral border of the humerus and the lateral intermuscular septum.
The muscle fibers of the lateral head converge with those of the long and medial heads in the distal arm, forming part of the common triceps tendon. This robust tendon then functionally inserts as a single, confluent unit onto the olecranon process of the ulna. The primary action of the lateral head is to extend the elbow joint.
References
Tiwana MS, Sinkler MA, Bordoni B. Anatomy, Shoulder and Upper Limb, Triceps Muscle. [Updated 2023 Aug 28]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK536996/
Negrão JR, Mogami R, Ramirez Ruiz FA, Wagner FV, Haghighi P, Ward SR, Resnick DL. Distal insertional anatomy of the triceps brachii muscle: MRI assessment in cadaveric specimens employing histologic correlation and Play-doh® models of the anatomic findings. Skeletal Radiol. 2020 Jul;49(7):1057-1067. doi: 10.1007/s00256-020-03382-3. Epub 2020 Jan 28. Erratum in: Skeletal Radiol. 2020 Jul;49(7):1069-1071.
