Overview
The arm is divided into anterior and posterior compartments by the medial and lateral intermuscular septa.
Anterior compartment
Muscles
- Biceps brachii
- Brachialis
- Coracobrachialis
Nerve
- Musculocutaneous nerve
Main arterial supply
- Brachial artery
Posterior compartment
Muscle
- Triceps brachii
Nerve
- Radial nerve
Key relationship
- Radial nerve and profunda brachii run in the spiral groove posteriorly
Important surface anatomy
- Median nerve accompanies the brachial artery medially
- Ulnar nerve passes medially and then posterior to the medial epicondyle distally
- Basilic vein is medial, cephalic vein lateral
Clinical relevance
- Compartment syndrome of the arm is uncommon but can occur
- Shaft humeral fractures may injure the radial nerve
- Surgical approaches require knowledge of neurovascular relationships
Diagram
