What is Radial Nerve Palsy

Radial nerve palsy is the loss of function of the radial nerve in your arm or hand. The radial nerve extends from your shoulder, around the back of your upper arm, and down the outside of your lower arm.

An injury to this nerve causes certain muscles and tendons in your arm and wrist not to work properly, which leads to a condition known as wrist drop. This means that you cannot extend your wrist.

If you are standing with your arm stretched straight out in front of you, your wrist will bend and your hand will drop down toward the floor.

An injury to the radial nerve may also result in lost feeling (sensation) in parts of your arm.

What are the causes?

Common causes of this condition include:

• A break (fracture) of your upper or lower arm bone.
• Complications from surgery.
• Improper use of crutches. Crutches that are too long can put pressure on the radial nerve where it passes through the armpit (crutch palsy).
• Keeping your arm in a position that places prolonged pressure on the radial nerve, such as by sleeping with arms over the back of a chair (Saturday night palsy).
• Performing repetitive activities that involve rotation of your lower arm or movement of your wrist (repetitive use injury).

What increases the risk?

You are more likely to develop this condition if you:

• Play contact sports.
• Have a condition in which your body’s immune system attacks your joints (rheumatoid arthritis).
• Have diabetes.
• Have an underactive thyroid (hypothyroidism).

What are the signs or symptoms?

Symptoms of this condition include:

• Inability to extend your wrist.
• Difficulty straightening your elbow and wrist.
• Numbness or tingling in the back of your arm, forearm, or hand.
• Inability to pinch.
• Muscle of the injured arm looking smaller.

How is this diagnosed?

This condition is diagnosed with a history of the injury and a physical exam. To confirm the diagnosis, you may also have tests, including:

• Ultrasound. This test show if the nerve has an injury.
• Nerve conduction studies. These tests show if the radial nerve is sending electrical signals well.
• X-rays. These may be done if your health care provider suspects that you have an injury to the bones in your arm.
• MRI. This may be used to determine the cause of your radial nerve palsy or to rule out other causes of your symptoms.

How is this treated?

Treatment for this condition depends on the cause. It may involve:

• Medicines.
  • NSAIDs may be used to control pain.
  • A steroid injection may be used to decrease swelling around the nerve.
• Physical and occupational therapy. This may help you:
  • Regain strength in your hand and wrist. 
  • Maintain range of motion of your wrist and elbow.
• Splinting. Your health care provider may make one or more splints for you to wear during the day or at night to help with motion and positioning of your wrist.
• Removing pressure on the radial nerve. This is done if the condition is caused by pressure on the nerve. Using this treatment may allow the nerve to go back to normal within a few weeks or a few months.
• Surgery. Depending on the cause of your radial nerve palsy, surgery may be needed to:
  • Remove pressure on the nerve (entrapment).
  • Repair broken bones.
  • Relocate (transfer) tendons in your lower arm to help you regain strength and mobility of your wrist.
  • Transfer a nerve to the injury site to restore nerve function.

Follow these instructions at home:

If you have a splint or brace

• Wear the splint or brace as told by your health care provider. Remove it only as told by your health care provider.
• Loosen the splint or brace if your fingers tingle, become numb, or turn cold and blue.
• Keep the splint or brace clean.
• If the splint or brace is not waterproof:
  • Do not let it get wet.
  • Cover it with a watertight covering when you take a bath or a shower.

Managing pain, stiffness, and swelling

• If directed, put ice on the injured area:
  • If you have a removable splint or brace, remove it as told by your health care provider.
  • Put ice in a plastic bag.
  • Place a towel between your skin and the bag.
  • Leave the ice on for 20 minutes, 2–3 times a day.
• Move your fingers often to avoid stiffness and to lessen swelling.
• Raise (elevate) the injured area above the level of your heart while you are sitting or lying down.

General instructions

• Follow your health care provider’s instructions about how to protect your hand and wrist.
• Protect your hand from extreme temperature injuries, such as burns and frostbite.
• Exercise your hand, wrist, and arm on a regular basis, as directed by your health care provider or therapist.
• Keep all follow-up visits as told by your health care provider. This is important.

Contact a health care provider if you:

• Have a sudden increase in pain.
• Develop new numbness or new loss of sensation in your hand.

Get help right away if you:

• Have a sudden change in your ability to move your arm, wrist, or hand.
• Notice your fingers become bluish in color or feel cold to the touch.

Summary

• Radial nerve palsy is the loss of function of the radial nerve in your arm or hand. That nerve extends from your shoulder, around the back of your upper arm, and down the outside of your lower arm.
• An injury to the radial nerve causes certain muscles and tendons in your arm and wrist not to work properly. This makes you unable to extend your wrist (a condition known as wrist drop). You may also lose feeling (sensation) in parts of your arm.
• Treatment for this condition depends on the cause. It may include removing pressure on the radial nerve, physical and occupational therapy, splinting, medicines, or surgery.