Peripheral nerves send messages from the brain and spinal cord to the rest of the body. They help do things such as sense that the feet are cold and move the body's muscles for walking. Peripheral nerves are made of fibers called axons that are insulated by surrounding tissues.
Peripheral nerves are fragile and easily damaged. A nerve injury can affect the brain's ability to communicate with muscles and organs. Damage to the peripheral nerves is called peripheral neuropathy.
It's important to get medical care for a peripheral nerve injury as soon as possible. Early diagnosis and treatment may prevent complications and permanent damage.
With a peripheral nerve injury, you may experience symptoms that range from mild to seriously limiting your daily activities. Your symptoms often depend on which nerve fibers are damaged:
- Motor nerves. These nerves regulate all the muscles under your conscious control, such as those used for walking, talking and holding objects. Damage to these nerves is typically associated with muscle weakness, painful cramps and uncontrollable muscle twitching.
- Sensory nerves. Because these nerves relay information about touch, temperature and pain, you may experience a variety of symptoms. These include numbness or tingling in the hands or feet. You may have trouble sensing pain or changes in temperature, walking, keeping your balance with your eyes closed, or fastening buttons.
- Autonomic (aw-tuh-NOM-ik) nerves. This group of nerves regulates activities that are not controlled consciously, such as breathing, heart and thyroid function, and digesting food. Symptoms may include excessive sweating, changes in blood pressure, the inability to tolerate heat and gastrointestinal symptoms.
You may experience a range of symptoms because many peripheral nerve injuries affect more than one type of nerve fiber.
When to see a doctor
If you experience weakness, tingling, numbness or a total loss of feeling in a limb, see your health care provider to determine the cause. It's important to treat peripheral nerve injuries early.
Peripheral nerves can be damaged in several ways:
- Injury from an accident, a fall or sports, which can stretch, compress, crush or cut nerves
- Medical conditions, such as diabetes, Guillain-Barre syndrome and carpal tunnel syndrome
- Autoimmune diseases including lupus, rheumatoid arthritis and Sjogren's syndrome
Other causes include narrowing of the arteries, hormonal imbalances and tumors.