Radial Nerve Injury

Alternate Names
radial nerve trauma
radial nerve damage

Definition of Radial Nerve Injury

The radial nerve attaches to the skin and muscles of certain areas of the arm, forearm, and hand, particularly the thumb and forefingers. It makes possible sensation in and movement of these parts. Someone with an injury to the radial nerve may lose function in these areas. In most cases, the radial nerve is damaged by trauma, repeated use of the nerve, or because the nerve is being compressed by other structures. The injury may be permanent.

What are the signs and symptoms of the injury?

Symptoms of a radial nerve injury depend on where the nerve injury occurs, but may include:

• numbness or tingling of the skin on the back of the arm, forearm, and hand
• pain in the same areas as the numbness or tingling
• muscle weakness, which usually affects the ability to straighten the elbow, wrist, and fingers
• muscle shrinkage or wasting, which takes a long time to develop
• deformities in the hand or forearm, usually due to muscle wasting

Symptoms may also result from the injury that caused the nerve damage.

What are the causes and risks of the injury?

Radial nerve injury can be caused by a number of activities, including:

• the improper use of crutches, usually when a person rests his or her weight on the armpits rather than the hands
• hanging the arms over the back of a chair for too long or lying on an arm for too long. This is sometimes called "Saturday night palsy," because it often happens in those who are very intoxicated with alcohol.
• a bone fracture involving the upper arm bone, or humerus

Rarely, no cause can be found for the nerve damage. In these cases, the injury may come from certain repeated motions of the arm, known as a repetitive stress injury. A radial nerve injury may be permanent, causing lifelong weakness and numbness, and sometimes chronic pain.

In some people, the muscles can shrink and cause the arm to become deformed over time. In other people, some or all of the arm's function may be regained over time.

What can be done to prevent the injury?

Most cases of radial nerve injury cannot be prevented. Avoiding injury, overuse of the arm, and improper use of crutches can prevent some cases.

How is the injury recognized?

A radial nerve injury can often be diagnosed with a history and physical exam. Tests may be ordered to help figure out the cause of the nerve injury. An x-ray of the arm is commonly done to look for a break or other bone injury.

A test called a nerve conduction velocity (NCV) study may be done to determine the location of the nerve injury. This test involves attaching wires to the skin. Small shocks are used to stimulate the nerve and measure its function.

Blood tests or a nerve biopsy are sometimes needed in unusual cases. A biopsy is a procedure to remove a small piece of tissue from the body. A special tool or needle can be inserted through the skin and into the nerve. A small piece of the nerve can be removed with the tool and sent to the lab for further examination and testing.

What are the treatments for the injury?

When the radial nerve injury is caused by a broken bone, fixing the bone by surgery or casting may reverse the nerve injury or at least result in some return of function.

Other treatments may include:

• pain medications, such as aspirin or ibuprofen
• other medications to help with nerve pain, such as amitriptyline or gabapentin
• physical therapy to help improve arm use and strength
• occupational therapy to help the person improve his or her ability to perform daily activities

What are the side effects of the treatments?

Surgery may be complicated by bleeding, infection, or an allergic reaction to the anesthetic. Aspirin and other pain medications may cause stomach upset, allergic reactions, or kidney damage. Other side effects depend on the specific medication used.

What happens after treatment for the injury?

Treatment for a radial nerve injury may or may not be able to reverse the lost function in the person's arm. Someone who does not recover fully often benefits from long-term physical therapy and occupational therapy. Deformity of the hand and muscle shrinkage can occur in severe cases.

Some people may recover completely and need no further treatment. The healthcare professional can help people monitor the injury by measuring the strength and sensation in the affected areas. Some of the medications used to treat pain may also need monitoring with blood tests. Any new or worsening symptoms should be reported to the healthcare professional.