What are the compartments of the arm and how are they formed?

The arm is divided into two main compartments: the anterior compartment and the posterior compartment. These are formed by deep fascia and two intermuscular septa (medial and lateral) that attach to the humerus bone.

Which structures pass between the arm compartments?

Several structures pierce the intermuscular septa to move between compartments: the ulnar nerve and superior ulnar collateral artery pass through the medial septum, and the radial nerve and radial collateral artery pass through the lateral septum.

What muscles and nerves are found in the anterior compartment of the arm?

The anterior compartment contains the biceps brachii, coracobrachialis, and brachialis muscles. It is primarily supplied by the musculocutaneous nerve.

What is the main muscle and nerve supply of the posterior compartment of the arm?

The posterior compartment is dominated by the triceps brachii muscle (with long, lateral, and medial heads). It is innervated by the radial nerve.

Which arteries supply the anterior and posterior compartments of the arm?

The brachial artery supplies the anterior compartment, while the profunda brachii artery supplies the posterior compartment.

What nerves are present in the anterior compartment besides its primary nerve supply?

In addition to the musculocutaneous nerve, the anterior compartment contains the median nerve, ulnar nerve (in its upper part), and radial nerve (in its lower part after piercing the lateral septum).

Arm Compartments – Anterior & Posterior Anatomy