Radial nerve dysfunction

Damage to one nerve, such as the radial nerve, is called mononeuropathy. Mononeuropathy means there is damage to a single nerve. Diseases affecting the entire body (systemic disorders) can also cause isolated nerve damage.

Causes of mononeuropathy include:

• An illness in the whole body that damages a single nerve
• Direct injury to the nerve
• Long-term pressure on the nerve
• Pressure on the nerve caused by swelling or injury of nearby body structures

Radial neuropathy occurs when there is damage to the radial nerve, which travels down the arm and controls:

• Movement of the triceps muscle at the back of the upper arm
• Ability to bend the wrist and fingers backward
• Movement of the wrist and hand
• Sensation of part of the back of the hand

When damage destroys the nerve covering (myelin sheath) or part of the nerve itself, nerve signaling is slowed or prevented.

Damage to the radial nerve can be caused by:

• Broken arm bone and other injury
• Diabetes
• Improper use of crutches leading to excess pressure in the armpit
• Lead poisoning
• Long-term or repeated constriction of the wrist (for example, from wearing a tight watch strap)
• Long-term pressure on the nerve, usually caused by swelling or injury of nearby body structures
• Pressure to the upper arm from arm positions during sleep or coma

In some cases, no cause can be found.

Radial nerve dysfunction is a problem with the radial nerve. This is the nerve that travels from the armpit down the back of the arm to the hand. It helps you move your arm, wrist, and hand.

Your health care provider will examine you and ask about your symptoms and medical history. You may be asked what you were doing before the symptoms started.

Tests that may be needed include:

• Blood tests
• Imaging tests to view the nerve and nearby structures
• Electromyography to check the health of the radial nerve and the muscles it controls
• Nerve biopsy to examine a piece of nerve tissue (rarely needed)
• Nerve conduction tests to check how fast nerve signals travel

If the cause of the nerve dysfunction can be found and successfully treated, there is a good chance that you will fully recover. In some cases, there may be partial or complete loss of movement or sensation.

Complications may include:

• Mild to severe deformity of the hand
• Partial or complete loss of feeling in the hand
• Partial or complete loss of wrist or hand movement
• Recurrent or unnoticed injury to the hand

Avoid prolonged pressure on the upper arm.

Craig A. Neuropathies. In: Cifu DX, ed. Braddom's Physical Medicine and Rehabilitation. 6th ed. Philadelphia, PA: Elsevier; 2021:chap 41.

Jobe MT, Martinez SF, Weller WJ. Peripheral nerve injuries. In: Azar FM, Beaty JH, eds. Campbell's Operative Orthopaedics. 14th ed. Philadelphia, PA: Elsevier; 2021:chap 62.

Katirji B. Disorders of peripheral nerves. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 106.

Patterson JMM, Novak CB, Mackinnon SE. Compression neuropathies. In: Wolfe SW, Pederson WC, Kozin SH, Cohen MS, eds. Green's Operative Hand Surgery. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 28.

Symptoms may include any of the following:

• Abnormal sensations in the back and thumb side of the hand, or in the thumb, 2nd, and 3rd fingers
• Weakness, loss of coordination of the fingers
• Problem straightening the arm at the elbow
• Problem bending the hand back at the wrist, or holding the hand
• Pain, numbness, decreased sensation, tingling, or burning sensation in the areas controlled by the nerve

The goal of treatment is to allow you to use the hand and arm as much as possible. Your provider will find and treat the cause, if possible. Sometimes, no treatment is needed and you will get better on your own.

If medicines are needed, they may include:

• Over-the-counter or prescription pain medicines
• Corticosteroid injections around the nerve to reduce swelling and pressure

Your provider will likely suggest self-care measures. These may include:

• A supportive splint at either the wrist or elbow to help prevent further injury and relieve the symptoms. You may need to wear it all day and night, or only at night.
• An elbow pad if the radial nerve is injured at the elbow. Also, avoid bumping or leaning on the elbow.
• Physical therapy exercises to help maintain muscle strength in the arm.

Occupational therapy or counseling to suggest changes in the workplace may be needed.

Surgery to relieve pressure on the nerve may help if the symptoms get worse, or if there is proof that part of the nerve is wasting away.

Contact your provider if you have an arm injury and develop numbness, tingling, pain, or weakness down the back of the arm and the thumb and your first 2 fingers.