Radial Nerve

What is the radial nerve?

Your radial nerve is a peripheral nerve that supplies movement and sensory function to parts of your arm, forearm, wrist and hand. You have a radial nerve in each of your arms. It’s called “radial” because part of it runs alongside the radius bone (and the radial artery) in your forearm.

Nerves are like cables that carry electrical impulses between your brain and the rest of your body. These impulses help you feel sensations and move your muscles.

What is the function of the radial nerve?

The function of your radial nerve is to supply movement (motor) and sensory information between your brain and parts of your arm, wrist and hand.

The motor branch of your radial nerve stimulates the:

• Triceps muscles on the back of your upper arm to straighten your elbow.
• Muscles in the outer part of your forearm that rotate your forearm and straighten (extend) your wrist and fingers.

The sensory branch of your radial nerve provides touch, pain and temperature sensations for the skin on:

• Your inner upper arm.
• Your outer forearm.
• The back part of your wrist and hand that’s closest to your thumb.

Some of the other nerves responsible for movement and sensations in your arm include your:

• Axillary nerve.
• Median nerve.
• Musculocutaneous nerve.
• Ulnar nerve.

Where is the radial nerve?

All of your peripheral nerves — including your radial nerves — are branches of other nerves in your body that originate from your spinal cord. If your spinal cord is the trunk of a tree, your peripheral nerves are its branches or roots. To understand your radial nerve, it helps to know where it starts and ends.

Your radial nerve is one of five nerve branches that extend from your brachial plexus. The brachial plexus nerves start from nerves that extend from your spinal cord (nerve roots) in your lower neck (cervical spine) and upper chest (thoracic spine). They travel underneath your collarbone (clavicle) and through your armpit.

Your radial nerve starts at your lower armpit. From there, it has a winding path, like a gently curving river. Your radial nerve:

• Wraps around your humerus — the long upper arm bone that runs from your shoulder to your elbow.
• Provides several smaller branches that supply motor (movement) function to muscles or sensory functions to the skin in your upper arm.
• Passes through the radial tunnel, a narrow opening between bone and muscle at the outside of your elbow.

At your elbow, your radial nerve splits into two major branches:

• A superficial branch: This branch only provides sensory information. This branch travels from just below your elbow to your wrist and into your hand and fingers. In your forearm, it runs alongside the radial artery, one of the blood vessels that supply blood to your forearm and hand.
• A deep branch: This branch runs between muscles in your forearm that help you rotate your forearm. It also stimulates several muscles to make your wrist, hand and fingers extend (such as when you open your hand from a clenched fist position). This nerve branch ends at your wrist.

What are the common conditions that affect the radial nerve?

Certain conditions and problems can cause radial nerve injury. It typically happens when there’s pressure on your radial nerve, causing a pinched nerve and nerve (neuropathic) pain.

Conditions that affect your radial nerve include:

• Radial nerve entrapment: This happens when your radial nerve gets injured or compressed (squeezed) anywhere along its path. It can result in pain and sensory and/or movement issues depending on where it’s compressed.
• Radial tunnel syndrome: This happens when your radial nerve is compressed specifically in the radial tunnel. This is a natural tunnel formed by muscles and ligaments in your elbow and forearm area that your radial nerve runs through. If you have this syndrome, the area around your elbow may hurt and you may have weakness in your forearm and wrist.
• Radial nerve palsy: “Palsy” means weakness or paralysis. This can happen when you sleep on an outstretched arm, have compression in your armpit from crutches or have a humerus bone fracture. If you injure your radial nerve, you may have symptoms like weakness and numbness. You may not be able to control the muscles that this nerve supplies. It’s the main cause of wrist drop.
• Wartenberg syndrome (cheiralgia paresthetica): This is a type of mononeuropathy that affects your radial nerve. It happens when muscles trap or compress the nerve’s superficial sensory branch in your wrist.

What are the symptoms of radial nerve damage?

Symptoms of radial nerve damage can vary based on where your radial nerve is injured.

One consistent symptom is radial nerve pain (radial nerve neuropathy). You may have the following sensations in your arm, wrist and/or hand:

• Pain.
• Burning.
• Itching.
• Tingling.
• Numbness.

Other signs of radial nerve damage may include:

• Arm, wrist or hand weakness or paralysis.
• Difficulty straightening your 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 keep my radial nerves healthy?

These steps can help keep your radial nerves — and your nervous system — healthy:

• Avoid prolonged pressure on your armpits, elbows and arms. If you have to use crutches, be sure to take frequent breaks.
• Follow safety best practices when participating in high-impact activities. Humerus fractures can cause radial nerve damage.
• Manage chronic conditions that can damage nerves, like diabetes and high blood pressure.
• Seek help to quit smoking. Tobacco use slows blood flow to your nerves.
• Reach and maintain a weight that’s healthy for you.
• Be physically active and eat nutritious foods.
• Decrease stress through meditation, walking or other healthy techniques.

When should I call my healthcare provider?

You should call a healthcare provider if you experience:

• Difficulty picking up items.
• Inability to extend your arm, wrist, hand or fingers.
• Pain, numbness or weakness in your arm, wrist, hand or fingers.
• Wrist drop.