Posterior compartments of the forearms

Posterior Compartments of the Forearms

The forearms are 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 important roles in forearm movement and stability. These muscles can be further divided into superficial and deep layers.

Superficial Layer

The superficial layer of the posterior compartment includes the following muscles:

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 elbow joint.

2. Anconeus: This small triangular muscle is located on the lateral side of the elbow joint. It assists in extending the forearm and stabilizing the elbow joint.

Deep Layer

The deep layer of the posterior compartment includes the following muscles:

1. Supinator: This muscle is located on the lateral side of the forearm. It plays a crucial role in supination, which is the movement of the forearm that allows the palm to face upward.

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

3. Extensor carpi radialis longus and extensor carpi radialis brevis: These muscles are responsible for extending and abducting the wrist joint.

4. Extensor digitorum: This muscle extends the fingers and assists in wrist extension.

5. Extensor carpi ulnaris: Located on the medial side of the forearm, this muscle extends and adducts the wrist joint.

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 provides motor innervation to the muscles in the posterior compartments, 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, supplying oxygenated blood to the muscles and other structures 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 loss of function in forearm movement, pain, numbness, or tingling sensations. Common conditions include radial nerve entrapment, tennis elbow, and muscle strains.

See Also

• Anterior compartments of the forearms
• Forearm anatomy
• Muscles of the upper limb