Radial nerve palsy affects the radial nerve, which runs from the upper arm to the wrist and fingers. This condition can cause difficulties with arm and hand movement and sensation changes, ranging from temporary to lasting.
The Radial Nerve’s Role
The radial nerve originates from a network of nerves in the neck and shoulder, known as the brachial plexus, carrying fibers from spinal nerves C5 through T1. It then travels down the back of the upper arm, wrapping around the humerus bone before continuing into the forearm. At the elbow, it divides into two main branches: a superficial sensory branch and a deep motor branch.
The radial nerve controls muscles for elbow extension (triceps), wrist and finger extension, and forearm supination (turning the palm upward). It also provides sensation to the back of the upper arm, outer forearm, and the back of the hand, including the thumb side and first three fingers.
What Leads to Radial Nerve Palsy
Radial nerve palsy frequently results from direct pressure or trauma to the nerve. Common scenarios include prolonged compression, such as “Saturday night palsy,” where the arm is pressed against a hard surface for an extended period, or “crutch palsy,” caused by pressure from crutches in the armpit. Direct trauma, like fractures of the humerus bone in the upper arm, dislocations, or deep cuts to the arm or wrist, can also damage the radial nerve.
Less common causes include tumors, cysts, infections, or inflammation pressing on the nerve. Symptoms include “wrist drop” (inability to extend the wrist and fingers), muscle weakness from the triceps to the fingers, and numbness, tingling, or burning in affected areas of the arm, hand, or fingers.
Identifying and Managing Radial Nerve Palsy
Diagnosing radial nerve palsy typically begins with a physical examination, where a healthcare provider assesses arm and hand movement, muscle strength, and sensation. To confirm the diagnosis and pinpoint the exact location and nature of the nerve damage, specific tests are often utilized. Nerve conduction studies (NCS) measure how quickly electrical signals travel along the nerve, while electromyography (EMG) evaluates the electrical activity of muscles at rest and during contraction. Imaging tests, such as X-rays, MRI, or ultrasound, can also be used to check for underlying causes like bone fractures, tumors, or other soft tissue issues that might be compressing the nerve.
Management approaches vary depending on the severity and cause of the palsy. Conservative treatments are often the first line of action. These include rest, activity modification to reduce pressure, and splints to support the wrist and hand, prevent “wrist drop,” and maintain joint position. Physical therapy, with specific exercises, helps maintain muscle strength and range of motion. Pain management, often with medication, can also be part of the treatment plan.
If conservative measures do not lead to improvement, or in cases of severe nerve damage, surgical intervention may be considered. This could involve nerve repair, decompression to relieve pressure, or tendon transfers to restore function if the nerve damage is irreparable.
What to Expect During Recovery
The recovery process for radial nerve palsy varies significantly. Outcome depends on the cause and severity of nerve damage, such as compression versus a complete laceration.
Recovery times range from weeks for mild compression to months or over a year for severe cases. Adherence to physical and occupational therapy is important to maintain muscle strength, improve range of motion, and facilitate function return. While many fully recover, some may have lingering symptoms or partial loss of function.