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Spinal Cord: Function, Anatomy and Structure

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.