The radial nerve is in the arm, and it helps control the movement of the triceps, the extension of the wrist and fingers, and the sensation in part of the hand.
Radial nerve injury can cause pain, weakness, and loss of function in the wrist, hand, and fingers. A common term for this is radial nerve palsy.
In this article, we will explain what the radial nerve is and why it is prone to injury. We will also look at the common causes, symptoms, and treatments for radial nerve palsy.
A radial nerve injury refers to damage to the nerve in the upper arm.
This nerve controls the triceps muscle. It also helps extend the wrist and fingers and provides sensation in part of the hand.
The radial nerve is close to the bone in the upper arm, so it is vulnerable to injury, especially if the arm breaks.
There are varying degrees of nerve damage:
- Neurapraxia, a first-degree injury, is the least serious classification.
- Axonotmesis refers to a second-, third-, or fourth-degree injury.
- Neurotmesis, a fifth-degree injury, is the most severe form of nerve damage.
Injury to the radial nerve can lead to radial nerve palsy.
The symptoms of radial nerve injury and resulting palsy include:
- weakness in the wrist, hand, or fingers
- loss of function in the wrist, hand, or fingers
The most common cause of radial nerve damage is a broken humerus, which is the bone that runs from the elbow to the shoulder.
A person can also sustain radial nerve damage during surgery on the arm, or from a gunshot.
Other causes of radial nerve injury include:
- a direct blow, such as those sustained during a car accident or sports injury
- injuries involving sharp objects, such as knives or glass
- sustained pressure, for example from using crutches incorrectly
- crush injuries
- sleeping on the arm
To diagnose a radial nerve injury, a doctor will perform a physical assessment. They will move each joint in the upper arm and ask the person to report any sensation of stretching, tingling, or pain.
In some cases, the doctor may do other tests to determine the exact location and severity of the injury. These include:
A nerve injury can slow or stop the transmission of electrical signals in the body. Measuring the speed and degree of these signals in the nerve can help with diagnosis.
There are two types of tests a doctor may use: electromyography and a nerve conduction study.
Medical imaging techniques, such as X-rays, ultrasounds, and MRIs can help locate and assess the severity of the nerve damage.
The treatment options depend on the cause and severity of the damage.
A minor neuropraxic injury will usually resolve itself, with sensation and function returning within a few hours or weeks at most. This is typical of minor damage, such as from sleeping on the arm.
For moderate injuries, a doctor may recommend rest and not using the arm whenever possible.
If the person is in pain, or the problem is due to swelling, over-the-counter nonsteroidal anti-inflammatory drugs such as ibuprofen can help.
Radial nerve palsy after a broken arm is very common. Up to 95 percent of people will make a full recovery without surgery. The doctor may recommend wearing a sling to keep the limb stable while it heals.
If the break was severe, or if the problem does not get better with rest and moderate treatment, a person may need surgery.
Procedures a doctor may recommend include:
This operation repairs the nerve. In some cases, a doctor may be able to sew the nerve back together.
If the nerve damage is too severe, they may employ nerve grafting or transfers. These procedures involve using nerves from other parts of the body to repair the damaged nerve.
This operation involves replacing a nonworking tendon with a working one from elsewhere in the body. It is a common treatment for nerve injury. A person will need general or local anesthetic.
After surgery, the person will usually wear a splint or cast for 1 or 2 months while the tendon heals. They will also need physical therapy to help them recover. It can take up to 1 year to know if the operation was successful.
Functional muscle transfer
If the damage is so extensive that a doctor cannot reconstruct the nerve, they may recommend a functional muscle transfer instead.
This is a relatively new procedure to replace a nonworking muscle with a “donor muscle” from elsewhere in the body.
Radial nerve injuries can lead to radial nerve palsy, which can cause pain and a loss of function in the arm, wrist, hands, and fingers. The most common cause of radial nerve injury is a broken arm.
Doctors usually recommend conservative methods, such as rest, but a person may also require surgery.