Axillary nerve dysfunction
Key points
- Axillary nerve dysfunction is a loss of movement or sensation of the shoulder because of damage to the axillary nerve.
- Axillary nerve dysfunction is a form of peripheral neuropathy.
- A neuromuscular examination of the arm and shoulder indicates axillary nerve dysfunction.
- Treatment is aimed at identifying the cause, treating it, and increasing mobility and independence.
Alternative names
Neuropathy - axillary nerve
Definition
Axillary nerve dysfunction is a loss of movement or sensation of the shoulder because of damage to the axillary nerve.
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. 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, and improper use of crutches. 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.
Symptoms
- Numbness over part of the outer shoulder
- Shoulder weakness
o Difficulty lifting objects with the affected arm
o Difficulty lifting arm above the head
Signs and tests
A neuromuscular examination of the arm and shoulder indicates axillary nerve dysfunction. There may be weakness of the shoulder, with difficulty moving the arm.
The deltoid muscle of the shoulder may show signs of muscle atrophy. A detailed history may be needed to determine the possible cause of the neuropathy.
Tests that reveal axillary nerve dysfunction may include:
- An EMG (a recording of electrical activity in muscles)
- A nerve biopsy (may reveal systemic causes for the dysfunction)
- An MRI to check for masses or lesions
Tests are given based on the suspected cause of the dysfunction suggested by the patient's history, symptoms, and pattern of symptom development. They may include various blood tests, , scans, or other tests.
Frequently asked questions
What is axillary nerve dysfunction?
Axillary nerve dysfunction is a loss of movement or sensation of the shoulder because of damage to the axillary nerve.
What are the risk factors for axillary nerve dysfunction?
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.
What are the symptoms of axillary nerve dysfunction?
- Numbness over part of the outer shoulder
- Shoulder weakness o Difficulty lifting objects with the affected arm o Difficulty lifting arm above the head
How is axillary nerve dysfunction treated?
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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