Spinal Nerves: Anatomy, Function, Diagram, Number, & Facts

The spinal nerves are the body’s major nerves within the peripheral nervous system (PNS). They link the spinal cord to the rest of the body, allowing messages to travel back and forth.

These nerves carry three types of signals: motor (movement), sensory (feeling), and autonomic (involuntary processes).

There are 31 pairs of spinal nerves, grouped by their location in the spine:

8 pairs of cervical nerves (C1-C8).

12 pairs of thoracic nerves (T1-T12).

5 pairs of lumbar nerves (L1-L5).

5 pairs of sacral nerves (S1-S5).

1 pair of coccygeal nerves (CO1).

Each pair connects to a specific section of the body, helping to control and sense that area.

spinal column
Spinal nerves are peripheral nerves that emerge from the spinal cord and carry motor, sensory, and autonomic signals between the spinal cord and the rest of the body. There are 31 pairs of spinal nerves: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal, named according to their corresponding vertebral levels.

How Spinal Nerves Work

Spinal nerves emerge from the spinal cord and split off to reach every corner of your body. They act like highways, carrying information to and from your brain.

Think of your spinal nerves like a two-way street:

  • On one side, sensory nerves are like delivery drivers bringing information (such as pain, touch, or temperature) from your skin and organs to your brain.
  • On the other side, motor nerves are like outgoing trucks carrying instructions from your brain to your muscles, telling them how to move.

Anatomy of Spinal Nerves

Each spinal nerve is formed from two roots:

  • The dorsal root brings sensory information into the spinal cord.
  • The ventral root sends motor commands out to the body.

These roots join together near the spine to form a spinal nerve. Some groups of nerves merge to form a large plexus of nerves, whereas some divide into smaller branches without forming a plexus.

Spinal nerves exit the spine through small openings between vertebrae called intervertebral foramina.

Key terms

💡 Dorsal Root: The back part of the spinal nerve where sensory information enters the spinal cord.

💡 Ventral Root: The front part of the spinal nerve where motor commands leave the spinal cord and travel to muscles.

💡 Plexus: A bundle of nerves that branch out and control specific body areas—like an electrical junction box that sends power to different rooms.

💡 Intervertebral Foramen: A small opening between two spine bones where nerves exit the spinal cord and travel to the body.

Diagram of the spinal cord

Function: Sensory and Motor Roles

Spinal nerves are mixed nerves, meaning they perform both sensory and motor functions:

  • Sensory: They carry signals from the skin, muscles, and organs to the spinal cord.
  • Motor: They deliver commands from the spinal cord to muscles, causing movement.

These signals allow you to do everything from lifting your arm to sensing heat or pain.

Spinal Nerve Groups

Cervical Nerves (C1–C8)

Located at the top of the spine, these nerves control the neck, shoulders, arms, and diaphragm:

  • C1–C3: Head and neck movement
  • C4: Upper shoulders and diaphragm (breathing)
  • C5: Deltoid and biceps (upper arms)
  • C6: Wrist extension and partial biceps
  • C7: Triceps and wrist extension
  • C8: Hand and finger flexion (grip)

C1–C5 form the cervical plexus, while C5–T1 contribute to the brachial plexus, which controls the arms and upper back.

Cervical nerves

Thoracic Nerves (T1–T12)

These nerves branch into the chest and abdominal muscles:

  • T1–T2: Upper chest, arms, and hands
  • T3–T5: Chest wall and breathing
  • T6–T8: Chest to abdomen
  • T9–T12: Abdomen and lower back
Thoracic nerve

Lumbar Nerves (L1–L5)

Located in the lower back, these nerves control the legs and lower body:

  • L1: Groin and genitals
  • L2–L4: Front thighs, hips, knees
  • L5: Outer lower legs and feet

L1–L4 form the lumbar plexus, which supports movement and sensation in the abdomen and legs.

lumbar plexus

Sacral Nerves (S1–S5)

These nerves manage the pelvis and back of the legs:

  • S1: Hips and groin
  • S2: Back of thighs
  • S3: Buttocks
  • S4–S5: Perineal area (genital and pelvic floor)

L4–S4 combine to form the sacral plexus, which includes the sciatic nerve (the body’s largest nerve).

Coccygeal Nerve (CO1)

This single nerve affects sensation around the tailbone and coccyx region.

Coccygea Nerves

Spinal Nerve Damage

Damage to spinal nerves can disrupt communication between the brain and body.

Imagine your spinal nerves as the electrical wiring in your house:

When everything is working, signals flow smoothly—lights turn on, appliances run, and everything functions as expected. But if the wires are pinched, frayed, or broken, the signals get disrupted.

In your body, this shows up as pain, tingling, weakness, or numbness when spinal nerves are damaged.

Symptoms of Spinal Nerve Damage

  • Pain (mild to severe)
  • Numbness or tingling in limbs
  • Muscle weakness
  • Loss of reflexes
  • Back or neck problems

💡 Reflexes: Automatic, rapid responses to certain stimuli—like when your knee jerks after being tapped.

Common Conditions That Affect Spinal Nerves

Compressive Neuropathy

Occurs when spinal nerves are compressed or pinched. This can be temporary or permanent, and often causes sharp pain or numbness.

Herniated Disc

Also called a “slipped disc,” this happens when a disc between vertebrae bulges out and presses on a nerve. It often causes pain, numbness, or weakness.

Herniated disc

Trauma

Injuries like falls or accidents can stretch, bruise, or tear spinal nerves. Neck injuries may affect the cervical plexus, while lower back injuries can impact the lumbar plexus.

Spinal Infections

Infections near spinal nerves can cause inflammation and pain, sometimes spreading symptoms to other body parts.

Guillain-Barré Syndrome (GBS)

This rare condition damages the myelin sheath that insulates nerves, weakening signal transmission.

Guillain Barre syndrome

Treatment Options

Treatment depends on the cause and severity of the nerve issue:

  • Over-the-counter or prescription pain relief
  • Anti-inflammatory medication
  • Physical therapy
  • Surgery (for severe compression or trauma)

If you experience ongoing symptoms like weakness or tingling, it’s important to seek medical advice.

References

Eidelson, S. G. (2019, June 3). Spinal Nerve Disorders. https://www.spineuniverse.com/conditions/sciatica/spinal-nerve-disorders

Moawad, H. (2020, January 18). The Anatomy of Spinal Nerves. Very Well Health. https://www.verywellhealth.com/spinal-nerves-anatomy-4682599#associated-conditions

Gorman, N. (2021, May 31). Spinal Nerves. Kenhub. https://www.kenhub.com/en/library/anatomy/spinal-nerves

Lumen. (n.d.). Spinal Nerves. Retrieved 2021, August 9 from: https://courses.lumenlearning.com/boundless-ap/chapter/spinal-nerves/

Spinal nerves chart and medical neural network in human body outline diagram. Labeled educational scheme with front and back neurology explanation

Karina Ascunce González

Neuroscience B.A. (Hons), Harvard University

PhD Neuroscience Student, Yale University

PhD Student at the Yale Biological & Biomedical Sciences' Interdepartmental Neuroscience Program interested in neurodegeneration, stem cell culture, and bioethics. AB in Neuroscience with a Secondary in Global Health & Health Policy from Harvard University. Karina has been published in peer reviewed journals.


Saul McLeod, PhD

BSc (Hons) Psychology, MRes, PhD, University of Manchester

Editor-in-Chief for Simply Psychology

Saul McLeod, PhD., is a qualified psychology teacher with over 18 years of experience in further and higher education. He has been published in peer-reviewed journals, including the Journal of Clinical Psychology.

Olivia Guy-Evans, MSc

Associate Editor for Simply Psychology

BSc (Hons) Psychology, MSc Psychology of Education

Olivia Guy-Evans is a writer and associate editor for Simply Psychology. She has previously worked in healthcare and educational sectors.

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