Spinal Cord

What is the spinal cord?

Your spinal cord is a cylindrical structure that runs through the center of your spine, from your brainstem to your low back. It's a delicate structure that contains nerve bundles and cells that carry messages from your brain to the rest of your body. Your spinal cord is one of the main parts of your nervous system.

What is the difference between the spinal cord and the vertebral column?

People often refer to the spinal cord and vertebral column together as the spine. Your spinal cord is a band of tissues, nerves and cells. A protective layer of bone called the vertebral column covers and protects your spinal cord.

The bones in the vertebral column are called vertebrae (plural of one spine bone, a vertebra). Your vertebrae stack on top of each other, from your pelvic bones to your skull. Between each pair of vertebrae, you have a spinal disk. Disks have a tough outer shell and a gel-like interior. They act as shock absorption and cushion for your vertebrae and spinal cord.

What is the purpose of the spinal cord?

Your spinal cord’s main purpose is to carry nerve signals throughout your body. These nerve messages have three crucial functions. They:

• Control body movements and functions. Signals from your brain to other body parts control your movements. They also direct autonomic (involuntary) functions like your breathing rate and heartbeat, as well as bowel and bladder function.
• Report senses to your brain. Signals from other parts of your body help your brain record and process sensations like pressure or pain.
• Manage your reflexes. Your spinal cord controls some reflexes (involuntary movements) without involving your brain. For example, your spinal cord manages your patellar reflex (involuntarily moving your leg when someone taps your shin in a certain spot).

What are the main parts of the spinal cord?

Your spinal cord has three main parts:

• Cervical (neck).
• Thoracic (chest).
• Lumbar (lower back).

What tissues and fluids make up the spinal cord?

Like your brain, layers of tissue called meninges cover the spinal cord. These protective tissues include:

• Dura mater. The outer layer that protects your spinal cord from injury.
• Arachnoid mater. The middle layer between the epidural and subarachnoid space.
• Pia mater. The inner layer that covers your spinal cord.

What are the epidural and arachnoid spaces?

The epidural space is between the dura mater and arachnoid mater. This space is where healthcare providers insert anesthesia during childbirth, known as epidurals.

The subarachnoid space is between the arachnoid mater and the pia mater. Here, cerebrospinal fluid (CSF) provides extra cushioning and protection for your spinal cord.

Sometimes, providers need to insert a needle into the subarachnoid space to test CSF for certain infections. This procedure is called a spinal tap. Both the epidural and arachnoid spaces provide extra shock absorption for your spine.

What nerves are in your spinal cord?

You have 31 pairs of nerves and nerve roots in your spinal cord. These include:

• Eight cervical nerve pairs (nerves starting in your neck and running mostly to your face and head).
• Twelve thoracic nerve pairs (nerves in your upper body that extend to your chest, upper back and abdomen).
• Five lumbar nerve pairs (nerves in the low back that run to your legs and feet).
• Five sacral nerve pairs (nerves in the low back extending into the pelvis).

You also have a nerve bundle at the base of your spinal cord called the cauda equina. The cauda equina comes from the Latin words for “horse’s tail,” because early anatomists thought the nerve collection looked like a horse tail. The cauda equina includes nerves that provide sensation to your lower body.

Your spinal nerves send electrical signals between your brain, spinal cord and the rest of your body. These electrical nerve signals help you feel sensations (sensory nerve) and move your body (motor nerves).

Where is the spinal cord located?

The spinal cord begins at the bottom part of your brainstem, called the medulla oblongata. At your lower back, your spinal cord forms a cone shape called the conus medullaris.

How long is your spinal cord?

In most adults, your spinal cord is about 18 inches (45 centimeters) long.

What conditions and disorders affect the spinal cord?

Many disorders or injuries can affect your spinal cord. Spinal cord injuries and disorders are serious. Any injury to your spinal cord can cause severe symptoms in the parts of your body below the injury.

Severe symptoms that can result from spinal cord damage can include loss of bladder control or paralysis. For some disorders, getting treatment quickly can lower your risk of long-term or permanent symptoms.

Common conditions that can affect your spinal cord include:

• Acute transverse myelitis. Inflammation in one or more segments of your spinal cord.
• Cervical spondylosis. Progressive wear-and-tear of the spinal disks in your neck (cervical disks) that can press on the spinal cord (cervical myelopathy).
• Herniated disks. when a spinal disk slips out of place and moves into the space around your spinal cord, pressing on nearby nerves.
• Spinal fractures. When one or more vertebrae are crushed (compression fracture) or broken (burst fracture) and put pressure on your spinal cord.
• Spinal muscular atrophy. A rare genetic condition where people lose motor nerve cells in the spinal cord, causing muscle weakness and atrophy (wasting away).
• Spinal stenosis. Narrowing of your spinal column, leading to pinched nerves and spinal cord irritation.
• Spinal tumors. Masses — which may be cancerous or not (benign) — that start in your spinal column and can put pressure on your spinal cord.
• Spinal infections. When the pressure of an expanding abscess or collapse of an infected vertebrae or disc puts pressure on the spinal cord.

How can I keep my spinal cord healthy?

You can keep your spinal cord, vertebral column and entire back healthier by practicing healthy habits. You may:

• Eat a nutritious diet with fruits, vegetables, whole grains, healthy fats and lean proteins.
• Exercise consistently, with a combination of aerobic activities, strengthening and stretching.
• Practice good posture and avoid hunching while sitting or standing.
• Quit smoking and using other tobacco products.
• Sleep in positions that support the natural curve of your neck and lower back.
• Walk often and take breaks throughout the day.
• Limit alcohol use and avoid using recreational drugs.

A note from Cleveland Clinic

Your spinal cord is the long, cylindrical structure that connects your brain and lower back. It contains tissues, fluids and nerve cells. A bony column of vertebrae surrounds and protects your spinal cord. Your spinal cord helps carry electrical nerve signals throughout your body. These nerve signals help you feel sensations and move your muscles. Any damage or injury to your spinal cord can affect your movement and function.