Injury of axillary nerve

Overview of axillary nerve injury

Overview

Diagram of the axillary nerve and its branches

The axillary nerve is a crucial component of the brachial plexus, responsible for innervating the deltoid muscle and the teres minor muscle, as well as providing sensory input from the skin overlying the deltoid. Injury to the axillary nerve can result in significant functional impairment of the shoulder.

Anatomy

The axillary nerve originates from the posterior cord of the brachial plexus, carrying fibers from the C5 and C6 spinal nerves. It travels through the quadrangular space of the shoulder, accompanied by the posterior circumflex humeral artery.

Branches

The axillary nerve gives off several branches:

• The anterior branch innervates the anterior part of the deltoid muscle.
• The posterior branch innervates the posterior part of the deltoid and the teres minor muscle.
• The superior lateral cutaneous nerve of the arm provides sensory innervation to the skin over the deltoid.

Causes of Injury

Injury to the axillary nerve can occur due to various reasons, including:

• Shoulder dislocation
• Fracture of the surgical neck of the humerus
• Compression from improper use of crutches
• Direct trauma to the shoulder region

Clinical Presentation

Patients with axillary nerve injury may present with:

• Weakness or paralysis of the deltoid muscle, leading to difficulty in abduction of the arm
• Atrophy of the deltoid muscle
• Loss of sensation over the lateral aspect of the shoulder

Diagnosis

Diagnosis of axillary nerve injury is primarily clinical, supported by:

• Physical examination
• Electromyography (EMG) and nerve conduction studies
• Magnetic resonance imaging (MRI) to assess the extent of injury

Management

Management of axillary nerve injury depends on the severity and cause of the injury:

• Conservative treatment includes physical therapy and pain management.
• Surgical intervention may be necessary in cases of severe or persistent injury, such as nerve grafting or nerve transfer.

Prognosis

The prognosis for axillary nerve injury varies. Many patients recover with conservative treatment, but some may experience persistent weakness or sensory deficits.

Related pages

• Brachial plexus injuries
• Peripheral nerve injury
• Shoulder anatomy