Posterior compartments of forearms

Posterior Compartments of Forearms

The human forearm is divided into anterior and posterior compartments, each containing various muscles, nerves, and blood vessels. In this article, we will focus on the posterior compartments of the forearms, exploring their anatomy and functions.

Muscles

The posterior compartments of the forearms consist of several muscles that play crucial roles in forearm movement and stability. These muscles can be further divided into superficial and deep groups.

Superficial Muscles

The superficial muscles in the posterior compartment include the following:

1. Triceps brachii: This is a large muscle located on the back of the upper arm. It consists of three heads - the long head, lateral head, and medial head. The triceps brachii is responsible for extending the forearm at the elbow joint.

2. Brachioradialis: Positioned on the lateral side of the forearm, the brachioradialis muscle assists in flexing the forearm at the elbow joint.

3. Extensor carpi radialis longus: This muscle runs along the lateral side of the forearm and is involved in extending and abducting the wrist.

4. Extensor carpi radialis brevis: Located next to the extensor carpi radialis longus, this muscle also contributes to wrist extension and abduction.

5. Extensor digitorum: As the name suggests, this muscle extends the fingers at the metacarpophalangeal and interphalangeal joints.

6. Extensor digiti minimi: Situated on the ulnar side of the forearm, this muscle extends the little finger at the metacarpophalangeal and interphalangeal joints.

Deep Muscles

The deep muscles in the posterior compartment include the following:

1. Supinator: This muscle is responsible for supination of the forearm, which involves rotating the palm to face upward.

2. Abductor pollicis longus: Located on the posterior side of the forearm, this muscle abducts the thumb at the carpometacarpal joint.

3. Extensor pollicis brevis: Positioned next to the abductor pollicis longus, this muscle extends the thumb at the metacarpophalangeal and interphalangeal joints.

4. Extensor pollicis longus: Running along the posterior side of the forearm, this muscle extends the thumb at the interphalangeal joint.

5. Extensor indicis: Situated between the extensor pollicis longus and extensor digitorum, this muscle extends the index finger at the metacarpophalangeal and interphalangeal joints.

Nerves

The posterior compartments of the forearms are innervated by the radial nerve, which is a major nerve of the upper limb. The radial nerve supplies motor innervation to most of the muscles in the posterior compartment, allowing for their contraction and movement.

Blood Supply

The blood supply to the posterior compartments of the forearms is primarily provided by the radial artery. This artery runs along the radial side of the forearm, giving off branches that supply oxygenated blood to the muscles and tissues in this region.

Clinical Significance

Injuries or conditions affecting the muscles, nerves, or blood vessels in the posterior compartments of the forearms can lead to various clinical manifestations. These may include weakness or paralysis of forearm movement, sensory deficits, or impaired blood flow.

See Also

• Anterior compartments of forearms
• Human forearm anatomy
• Radial nerve
• Radial artery