Definition of Axillary nerve dysfunction:

Axillary nerve dysfunction is nerve damage that leads to a loss of movement or sensation in the shoulder.

Causes, incidence, and risk factors:

Axillary nerve dysfunction is a form of peripheral neuropathy. It occurs when there is damage to the axillary nerve, which supplies the deltoid muscles of the shoulder and the skin around it. A problem with just one nerve, such as the axillary nerve, is called mononeuropathy.

The usual causes are:

• Direct trauma
• Long-term pressure on the nerve
• Pressure on the nerve from nearby body structures
• Shoulder injury

Entrapment creates pressure on the nerve where it passes through a narrow structure.

The damage may destroy the myelin sheath that covers the nerve, or part of the nerve cell (the axon). Damage of either type reduces or prevents the movement of impulses through the nerve.

Conditions that can lead to axillary nerve dysfunction include:

• Body-wide (systemic) disorders that cause nerve inflammation
• Deep infection
• Fracture of the upper arm bone (humerus)
• Pressure from casts or splints
• Improper use of crutches
• Shoulder dislocation

In some cases, no cause can be found.