Radial nerve dysfunction occurs when there is damage to the radial nerve, which travels down the arm. It aids the movement of the triceps muscle located at the back of the arm, as well as facilitates extension at the wrist and sensation in the wrist and hand. Radial nerve dysfunction is generally caused by a direct trauma, long-term pressure on the nerve, or compression resulting from nearby swelling or injury. It is most commonly associated with fractures of the humerus or upper arm bone, but may also result from unusual compression to the underarm, such as using crutches for an extended period of time.
Radial nerve dysfunction is a form of peripheral neuropathy. When a single nerve group such as the radial nerve is damaged it is called a mononeuropathy, which indicates a single, local cause of nerve damage.
Symptoms may include difficulty extending the arm at the elbow, as well as difficulty extending the wrist. There may also be some numbing, reduction in sensation, a burning sensation and pain. Depending on the severity of the case, patients may experience a wrist drop or finger drop, as a result of a weakened muscle.
Those at Risk
Those sustaining trauma to the upper arm and those subjected to crutches for an extended period of time are at risk for this condition.
Following patient history, and neuromuscular examination of the arm, hand and wrist, diagnosis of radial nerve dysfunction may also involve an electromyogram (EMG) to verify that muscles at the back of the upper arm are working properly. Improper functioning of the muscle is generally caused by a malfunction in the supervising nerve. A nerve conduction velocity (NCV) test may also be used, in order to measure the speed of an electrical impulse as it travels along the radial nerve. A slow speed indicates an entrapped nerve.
The first phase of treatment for radial nerve dysfunction in the triceps is conservative and includes refraining from the activity responsible for the condition, as well as those irritating the condition. A lightweight plastic removable arm splint may be indicated at night if pain worsens during sleep. A patient-specific physical or occupational therapy program is established in order to increase the success of the other conservative treatment plans.
When the condition is nonresponsive to conservative treatment and symptoms persist, an outpatient procedure that helps to decompress the nerve may be indicated.
And following all treatment options is a rehabilitation program that demonstrates correct alignment and positions during activity. It also includes active range of motion and stretching exercises – possibly combined with a soft-tissue massage. Isometric exercises following a surgical procedure helps to improve upper arm and hand strength – while placing minimal stress on the tissues near the recovering nerve.