Radial Nerve Injury
Damage to the nerve that lifts the wrist and fingers
Quick Facts
- Type: Peripheral nerve injury
- Hallmark sign: Wrist drop (inability to lift the wrist)
- Common causes: Pressure, arm fractures, deep cuts
- Outlook: Many cases recover with time and therapy
Overview
The radial nerve runs from the shoulder down the back of the arm and forearm. It controls the muscles that straighten (extend) the elbow, wrist, and fingers, and it carries sensation from part of the back of the hand. A radial nerve injury is any damage that interrupts these signals.
The most recognizable result is wrist drop, where the hand hangs limply because the wrist and fingers cannot be lifted against gravity. The injury can range from temporary pressure on the nerve, which often recovers fully, to a complete cut or stretch that needs surgical repair. The cause and severity largely determine how well and how quickly the nerve recovers.
Symptoms
Symptoms depend on where along its course the nerve is injured and how severely. They can include:
- Wrist drop: Inability to lift the wrist and fingers, so the hand droops.
- Weakness when straightening the elbow, wrist, or fingers
- Difficulty gripping or holding objects firmly
- Numbness or tingling over the back of the hand and thumb side
- A weakened grip, since the wrist cannot be stabilized
Symptoms may appear suddenly after an injury or gradually if the nerve is being compressed over time.
Causes
The radial nerve is vulnerable where it wraps around the upper arm bone. Common causes of injury include:
- Prolonged pressure: Falling asleep with the arm draped over a chair or bed rail (sometimes called "Saturday night palsy") or pressure from improperly fitted crutches.
- Fractures: Breaks of the upper arm bone (humerus) can stretch or pinch the nerve.
- Deep cuts or puncture wounds in the arm.
- Repetitive strain or compression at the elbow.
- Pressure during deep sleep, surgery, or intoxication when a person does not shift position.
Risk Factors
- Fractures or dislocations of the arm
- Activities or positions that press on the upper arm for long periods
- Use of crutches that press into the armpit
- Heavy alcohol or sedative use leading to prolonged immobility
- Repetitive forceful arm movements
Diagnosis
Diagnosis is based on the pattern of weakness and numbness plus tests to locate and grade the injury:
- Physical examination: Checking wrist and finger extension, grip, and sensation on the back of the hand.
- Nerve conduction studies and electromyography (EMG): Measure how well the nerve and muscles are working and show the location and severity of damage.
- Imaging: X-rays for fractures, and sometimes ultrasound or MRI to look at the nerve directly.
Treatment
Treatment depends on the cause and severity. Many compression injuries recover on their own:
- Observation and time: Mild pressure injuries often heal over weeks to months as the nerve recovers.
- Splinting: A wrist splint supports the hand and prevents stiffness while strength returns.
- Physical and occupational therapy: Exercises maintain joint motion, prevent contractures, and rebuild strength.
- Surgery: Needed when the nerve is cut, severely stretched, or trapped by a fracture or scar tissue, or when there is no recovery over time.
Avoiding repeated pressure on the nerve is important so it can heal.
Prevention
- Avoid resting the arm over hard edges for long periods
- Use crutches that bear weight on the hands rather than the armpits
- Take care to change position during long periods of sitting or lying down
- Treat arm fractures promptly and follow rehabilitation advice
- Limit alcohol and sedatives that can lead to prolonged pressure during sleep
When to See a Doctor
See a doctor if you develop weakness or numbness in the hand and cannot lift your wrist, especially after an injury, a fall, or waking from heavy sleep. Seek prompt care if the symptoms follow an arm fracture or a deep cut, or if there is no improvement over a few weeks, as earlier treatment can improve recovery.
Frequently Asked Questions
What is wrist drop?
Wrist drop is the inability to lift the wrist and fingers, so the hand hangs limply. It is the hallmark of a radial nerve injury because the nerve controls the muscles that straighten the wrist and fingers.
Will a radial nerve injury heal on its own?
Many radial nerve injuries from temporary pressure recover on their own over weeks to months as the nerve regenerates. Injuries from a cut, severe stretch, or fracture that traps the nerve are more likely to need surgery.
What is Saturday night palsy?
Saturday night palsy is a radial nerve injury caused by prolonged pressure on the upper arm, classically from falling asleep with the arm draped over a hard surface. It often improves once the pressure is relieved and the nerve recovers.
How is a radial nerve injury treated?
Treatment ranges from observation and a supportive wrist splint with therapy for mild cases to surgery when the nerve is cut, badly stretched, or compressed. Physical therapy helps keep joints flexible and rebuild strength during recovery.
How long does recovery take?
Recovery varies widely. Mild compression injuries may improve within weeks to a few months, while more severe injuries can take many months and may be incomplete. Nerve conduction studies help estimate the outlook.
References
- American Academy of Orthopaedic Surgeons (OrthoInfo). Radial Tunnel Syndrome and Radial Nerve Injury.
- MedlinePlus, U.S. National Library of Medicine. Radial nerve dysfunction.
- National Institute of Neurological Disorders and Stroke (NINDS). Peripheral Neuropathy.