What is the radial nerve?
The radial nerve helps you move your elbow, wrist, hand and fingers. It runs down the back of the arm from the armpit to the hand.
The radial nerve is part of the peripheral nervous system. The peripheral nervous system sends signals from your brain to your arms and fingers, lower limbs, skin and internal organs.
What is the purpose of the radial nerve?
The radial nerve provides motor (movement) and sensory functions to the arm. It:
- Stimulates muscles so you can straighten and raise your elbows, wrists, hands and fingers.
- Provides touch, pain and temperature sensations to portions of the back of the upper arm, forearm, and to the back of the hand and fingers.
Where is the radial nerve?
The radial nerve is one of five terminal nerve branches that make up the brachial plexus. The brachial plexus is a complex bundle of nerves that control movements and sensations in your shoulders, arms, hands and fingers. These nerves start from the lower cervical area in the neck and the upper chest (thoracic) portion of the spine and travel underneath the collarbone (clavicle), and then through the armpit (axilla).
The radial nerve starts at the lower armpit. It originates from several nerve roots (where a nerve connects to the central nervous system) that run from the:
- C5 to C8 cervical vertebrae, the lowest spinal bones in the neck.
- T1 thoracic vertebra, the topmost upper-back/chest spinal bone.
From there, the nerve:
- Wraps around the humerus, the long upper arm bone that runs from the shoulder to the elbow.
- Passes through the radial tunnel, a narrow opening between bone and muscle at the outside of the elbow.
- Branches into smaller nerves .
- Travels down the outside of the forearm to the wrist, hand and fingers.
What are the radial nerve branches?
The radial nerve branches include:
- A superficial branch: This branch only provides sensory information. This branch travels from just below the elbow to the wrist and into the hand and fingers. In the forearm, it runs alongside the radial artery, one of the blood vessels that supplies blood to the forearm and hand.
- A deep branch: This branch runs between muscles in the forearm that help you rotate your forearm and stimulates several muscles to make your wrist, hand and fingers move upward. This nerve branch ends at the wrist.
What are the other nerves in the arm?
Some of the other nerves responsible for movement and sensations to the arm include the:
- Axillary nerve.
- Median nerve.
- Musculocutaneous nerve.
- Ulnar nerve.
Conditions and Disorders
What conditions and disorders affect the radial nerve?
- Radial tunnel syndrome: The radial tunnel (created by normal muscles and ligaments in the elbow and forearm area) can press on the radial nerve. Radial tunnel syndrome is also called radial nerve entrapment.
- Radial nerve palsy: Palsy is weakness, or paralysis of several forearm muscles that are responsible for wrist, hand and finger upward motion.
- Wartenberg syndrome: A type of mononeuropathy that affects the radial nerve. It occurs when muscles trap or compress the nerve’s superficial sensory branch in the wrist.
What causes radial nerve problems?
- Overuse injuries or prolonged pressure on the arms from casts or splints, or from simply laying on the nerve (which causes pressure) for a period of time.
- Complications from surgeries, such as shoulder replacements.
- Trauma, including accidents, gunshot injuries and knife wounds.
- Tumors or cysts.
What are the signs of radial nerve problems?
Signs of a radial nerve problem include:
- Hand or arm numbness, weakness, paralysis or pain.
- Difficulty straightening the elbows, wrists, hands or fingers.
- Problems grasping, pinching or picking up objects.
- Wrist drop (limply hanging wrist that you can’t lift).
How can I protect my radial nerves?
These steps can keep your nervous system healthy:
- Achieve and maintain a healthy weight.
- Be physically active and eat a nutritious diet.
- Decrease stress through meditation, walking or other healthy techniques.
- Don’t skimp on sleep.
- Manage conditions like diabetes and high blood pressure that damage nerves.
- Seek help to quit smoking. Tobacco use slows blood flow to nerves.
- Avoid prolonged pressure on your arms.
When should I call my doctor?
You should call your healthcare provider if you experience:
- Difficulty picking up items.
- Inability to extend the arm, wrist, hand or fingers.
- Pain, numbness or weakness in the arm, wrist, hand or fingers.
- Wrist drop.
A note from Cleveland Clinic
The radial nerves help you move your arm, wrist, hands and fingers. They also send information about touch, pain and temperature to your brain. A broken arm or dislocated shoulder can damage the radial nerve, leading to pain, weakness or numbness. A pinched nerve can cause radial tunnel syndrome or radial nerve palsy. You may have pain, weakness or paralysis in the arm, wrist or hands. These symptoms often improve with treatment.
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