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. It is not a specific, separate disease, but is caused by many conditions that can damage the axillary nerve.
Dysfunction of a single nerve group, such as the axillary nerve, is called mononeuropathy. Mononeuropathy implies a local cause of the nerve damage, although systemic disorders may occasionally cause isolated nerve damage (such as occurs with mononeuritis multiplex). The usual causes are direct trauma, prolonged external pressure on the nerve, and pressure on the nerve from nearby body structures.
Conditions associated with axillary nerve dysfunction include fracture of the humerus (upper arm bone), pressure from casts or splints, improper use of crutches, intramuscular injections, and shoulder dislocation. Other causes include systemic disorders that cause neuritis (inflammation of nerves). In some cases, no detectable cause can be identified. Mechanical factors may be complicated by ischemia (a lack of oxygen from decreased blood flow) in the area.
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