Posterior region of arm
Regio posterior brachii
- Latin synonym: Regio brachialis posterior
- Synonym: Posterior brachial region
Definition
The posterior region of arm or brachium is the extensor region, primarily dominated by the large triceps brachii muscle. This muscle comprises three distinct heads: the long head, lateral head, and medial head. The small anconeus muscle, located near the elbow, functionally assists the triceps brachii in elbow extension and is often considered part of this compartment.
The primary function of the muscles within the posterior region of arm is extension of the forearm at the elbow joint.
The main nerve supply to this region is the radial nerve, which, along with the profunda brachii artery, courses within the radial (spiral) groove of the humerus. This neurovascular bundle is crucial for the innervation and blood supply of the triceps brachii and anconeus muscles.
References
Alshammari SM, Bordoni B. Anatomy, Shoulder and Upper Limb, Arm Muscles. [Updated 2023 Jul 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554420/
Cho H, Lee HY, Gil YC, Choi YR, Yang HJ. Topographical anatomy of the radial nerve and its muscular branches related to surface landmarks. Clin Anat. 2013 Oct;26(7):862-9.
