Posterior compartments of the forearm

Posterior Compartments of the Forearm

The forearm is divided into anterior and posterior compartments by a layer of connective tissue known as the interosseous membrane. In this article, we will focus on the posterior compartments of the forearm, which contain several important muscles and structures.

Muscles

The posterior compartments of the forearm house several muscles that are responsible for various movements of the wrist, hand, and fingers. These muscles can be further divided into superficial and deep groups.

Superficial Group

The superficial group of muscles in the posterior compartment includes the following:

1. Triceps brachii: This muscle is located on the back of the upper arm but extends into the posterior compartment of the forearm. It is responsible for extending the elbow joint.

2. Anconeus: The anconeus muscle is a small triangular muscle that lies next to the triceps brachii. It assists in extending the elbow joint and stabilizing the ulna during pronation and supination of the forearm.

3. Brachioradialis: The brachioradialis muscle is a long muscle that runs along the lateral side of the forearm. It helps in flexing the forearm at the elbow joint.

Deep Group

The deep group of muscles in the posterior compartment includes the following:

1. Supinator: The supinator muscle is located deep in the posterior compartment and wraps around the upper part of the radius bone. It is responsible for supinating the forearm, which is the movement of turning the palm upward.

2. Extensor carpi radialis longus and extensor carpi radialis brevis: These two muscles are located on the lateral side of the forearm. They are responsible for extending and abducting the wrist joint.

3. Extensor digitorum: The extensor digitorum muscle is a long muscle that extends from the lateral side of the forearm to the fingers. It is responsible for extending the fingers at the metacarpophalangeal and interphalangeal joints.

Structures

Apart from muscles, the posterior compartments of the forearm also contain important structures such as nerves, blood vessels, and tendons.

1. Radial Nerve: The radial nerve is a major nerve that runs along the posterior aspect of the forearm. It provides sensory innervation to the back of the hand and motor innervation to several muscles in the posterior compartment.

2. Posterior Interosseous Artery: This artery is a branch of the ulnar artery and supplies blood to the deep muscles in the posterior compartment.

3. Extensor Retinaculum: The extensor retinaculum is a thick band of connective tissue that holds the tendons of the extensor muscles in place as they pass over the back of the wrist.

Clinical Significance

Injuries or conditions affecting the posterior compartments of the forearm can result in various symptoms and functional limitations. For example, damage to the radial nerve can lead to weakness or paralysis of the muscles it innervates, causing difficulty in extending the wrist, fingers, and thumb.

Understanding the anatomy of the posterior compartments of the forearm is crucial for diagnosing and treating such conditions effectively.

See Also

• Anterior compartments of the forearm
• Forearm
• Muscles of the forearm