Organ5 min read
Peripheral nerves
Peripheral nerves lie outside the brain and spinal cord, carrying signals between the central nervous system and the rest of the body for movement, sensation and automatic functions.
Three types: motor, which control voluntary muscles; sensory, which carry touch, temperature and pain; and autonomic (involuntary), which regulate breathing, digestion, heartbeat and glands. Damage causes symptoms according to the type: weakness in motor nerves, numbness, tingling and pain in sensory nerves, and changes in sweating, digestion and pulse in autonomic nerves.
The most common cause of peripheral neuropathy is diabetes according to MedlinePlus, and other causes include injuries, infections, autoimmune diseases, kidney and liver diseases, some drugs and toxins, alcohol, smoking, vitamin B12 deficiency, and heredity. Diagnosis depends on the medical history, examination, blood tests, imaging, nerve conduction studies, electromyography and sometimes a biopsy (NINDS).
In one minute123
- What is it?
- The nerves outside the brain and spinal cord that connect the central nervous system to the rest of the body.
- Who is usually affected?
- Especially affected are people with diabetes, as well as those with injuries, infections or vitamin deficiency.
- Acute or chronic?
- Damage may progress over time depending on the cause.
- Main symptoms
- Numbness, tingling, pain, weakness and change in sweating or digestion (depending on the type).
- Red flags?
- Yes: numbness with weakness or slurred speech or a change in vision.
- Preventable?
- Controlling blood sugar, avoiding alcohol and smoking, and avoiding B12 deficiency.
What and where are they?
The peripheral nerves, "nerves outside the brain and spinal cord", branch from the central nervous system to reach all parts of the body (MedlinePlus), and are a communication network that sends signals between the central nervous system and the rest of the body (NINDS). They belong to the nervous system and connect to the brain and spinal cord.
Types and roles
| Type | Function | Symptoms of damage |
|---|---|---|
| Motor | Control the muscles we move voluntarily: walking, gripping and speaking | Weakness, cramps, muscle twitching, balance problems |
| Sensory | Carry light touch, temperature and pain | Tingling, numbness, pain, reduced sensation |
| Autonomic | Regulate what we do not consciously think about: breathing, digestion, heart rate and glands | Irregular pulse, difficulty swallowing, changes in sweating, digestive, urinary and sexual problems |
How it works
- 1SensationSensory nerves pick up touch, temperature and pain and carry them to the central nervous system.
- 2ProcessingThe brain and spinal cord process the information.
- 3CommandMotor nerves carry commands to the muscles.
- 4Automatic regulationAutonomic nerves regulate breathing, digestion and heart rate without conscious thought.
Links to other organs
- The brain and spinal cord
- The centre of the nervous system, to which the peripheral nerves connect, sending signals to it and receiving signals from it.
- The heart and the digestive system
- Autonomic nerves regulate heart rate and digestion; damage to them causes rhythm disturbances and digestive problems.
Conditions that affect them
MedlinePlus lists these main causes: diabetes (the most common), injuries, infections (such as HIV and Lyme disease), autoimmune diseases (such as rheumatoid arthritis and lupus), kidney or liver disease, certain medicines, exposure to toxins, alcohol misuse, smoking, vitamin B12 deficiency, and inherited conditions.
Related conditions that MedlinePlus mentions include carpal tunnel syndrome, sciatica, complex regional pain syndrome, brachial plexus injuries, Guillain-Barré syndrome and trigeminal neuralgia.
Tests used to study them
According to NINDS, doctors use the medical history, a physical examination, blood tests, MRI or CT imaging, nerve conduction studies, electromyography and sometimes a skin or nerve biopsy.
Factors linked to their health
Factors that the sources give as causes of peripheral nerve damage are linked to nerve health: diabetes (the most common), alcohol misuse, smoking and vitamin B12 deficiency. The page on diabetic neuropathy covers what is reported about managing it.
When do you need urgent help?
Call emergency services now 998
- Numbness or tingling with weakness, inability to move, slurred speech or a change in vision: seek emergency care (see the numbness and tingling page).4
See your doctor within days
- Persistent numbness, tingling, weakness or pain in the limbs that worsens over time: see a doctor.2
Educational content only — no diagnosis, and no substitute for a clinician.
References
- 1MedlinePlus. Peripheral Nerve Disorders. medlineplus.gov/peripheralnervedisorders.htmlHealth agencies & guidelines · Accessed 2026-10-06
- 2NINDS. Peripheral Neuropathy. www.ninds.nih.gov/health-information/disorders/peripheral-neuropathyHealth agencies & guidelines · Accessed 2026-10-06
- 3NIDDK / NIH. Diabetic Neuropathy. www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/nerve-damage-diabetic-neuropathiesHealth agencies & guidelines · Accessed 2026-10-03
- 4MedlinePlus. Numbness and tingling. medlineplus.gov/ency/article/003206.htmHealth agencies & guidelines · Accessed 2026-10-06
Review status: Edited content · Last updated:
Change log
- — Page created.
Educational content only — no diagnosis, and no substitute for a clinician.