Radial palsy describes a condition where the radial nerve, which runs down the arm, experiences damage or compression. This can lead to various degrees of weakness or paralysis in specific parts of the arm, wrist, and hand. It is a relatively common type of nerve injury that can significantly affect daily activities and overall arm function.
What is Radial Palsy
The radial nerve is one of the three major nerves in the arm, originating from nerve roots in the neck and extending down to the hand. Its primary function involves controlling muscles responsible for straightening the elbow, extending the wrist, and extending the fingers and thumb. It also provides sensation to the back of the hand, thumb, and the first two fingers.
When this nerve is injured, compressed, or otherwise compromised along its path, this disruption prevents it from sending proper signals to the muscles it controls, resulting in a loss of their ability to function. A characteristic sign is often referred to as “wrist drop,” where the wrist and fingers hang limply due to the inability to extend them.
Causes of Radial Palsy
Radial palsy can result from various incidents that place pressure on or directly injure the radial nerve. A frequent cause is prolonged compression of the nerve, often seen in situations like “Saturday night palsy” or “honeymoon palsy” where the arm remains in an awkward position for an extended period, such as draped over a chair or compressed by crutches. This sustained pressure can temporarily interrupt nerve signals.
Fractures of the humerus, the upper arm bone, are another common cause, as the radial nerve runs in close proximity to this bone and can be damaged during a break. Deep cuts or direct trauma to the arm, such as from sharp objects or crush injuries, can also sever or significantly harm the nerve. Less commonly, radial palsy may arise from nerve compression by tumors, cysts, or inflammation along the nerve’s pathway.
Signs and Symptoms
Individuals with radial palsy present with signs and symptoms related to impaired nerve function. A hallmark symptom is “wrist drop,” the inability to lift or extend the wrist and fingers. This makes everyday tasks requiring wrist and finger extension difficult.
Beyond wrist drop, weakness or difficulty in straightening the elbow may occur, especially if the injury is higher up the arm. Numbness, tingling, or a burning sensation can be felt along the back of the hand, thumb, and first two fingers, corresponding to the radial nerve’s sensory distribution. Additionally, people may struggle with grasping or manipulating objects due to weakness in their wrist and finger extensors.
Diagnosing Radial Palsy
Diagnosis of radial palsy begins with a physical examination. During this examination, muscle strength in the arm, wrist, and hand is assessed, testing the ability to extend the elbow, wrist, and fingers. Sensation along the radial nerve’s distribution on the back of the hand and forearm is also checked.
To evaluate nerve function, nerve conduction studies (NCS) and electromyography (EMG) may be performed. NCS measures how quickly electrical signals travel along the nerve, while EMG assesses the electrical activity of the muscles it supplies, helping pinpoint the location and severity of nerve damage. Imaging tests, such as X-rays, ultrasound, or MRI scans, may identify underlying causes like bone fractures, tumors, or other tissue damage that could be compressing the nerve.
Treatment Options
Treatment for radial palsy often begins with conservative approaches, particularly for compression-related cases. Splinting or bracing the wrist and hand is a common initial step, supporting the wrist in an extended position to prevent muscle tightening and allow nerve healing. This also helps maintain hand function during recovery.
Physical therapy plays a role, involving exercises to strengthen weakened muscles and maintain range of motion in affected joints. Occupational therapy also assists by teaching adaptive strategies and exercises to help individuals perform daily activities while the nerve recovers. Medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), may be prescribed to manage pain or reduce inflammation.
If conservative methods do not show improvement after several months (typically three to four months), or if there is evidence of a complete nerve tear, surgical intervention may be considered. Surgical options include direct nerve repair (reconnecting severed nerve ends) or nerve grafting (using a nerve segment from another body part to bridge a gap). In cases where nerve recovery is unlikely, tendon transfer procedures may be performed, rerouting healthy tendons to restore lost function.
Recovery and Outlook
The prognosis for radial palsy is often favorable, with many individuals, particularly those with compression-related conditions, experiencing a full recovery. Recovery timelines vary widely, from several weeks to many months, depending on the cause and severity of nerve damage. For instance, minor compression injuries may resolve within weeks, while more severe damage, such as from a fracture, could take six to eighteen months for full function to return.
Nerve regeneration occurs at about one millimeter per day, meaning recovery is a gradual process. Adherence to prescribed physical and occupational therapy is important for maximizing functional recovery and preventing complications like joint stiffness or muscle atrophy. Regular follow-up appointments allow for monitoring progress and adjustments to the treatment plan.