The spinal cord is a slender tubular-shaped structure about the diameter of the little finger. It begins at the base of the brain, at the brain stem, and extends downward and ends at the first lumbar, or low back, vertebrae, abbreviated L1.
The end of the spinal cord is called the conus medullaris. Thereafter, the cord splits into a bundle of nerves known as the cauda equina. The cauda equina resembles a horse’s tail.
How the Spinal Cord Is Protected
The structural design of the spine’s bony parts, such as the vertebral bodies and laminae, create a hollow tube. Inside the tube, the spinal cord is bathed and surrounded by cerebrospinal fluid, a colorless clear body fluid. Three membranes, called meninges, encase the spinal cord and provide additional protection.
Nerve Roots
Nerve roots branch off the spinal cord and exit the spinal canal through neuroforamen. Neuroforamen are nerve passageways naturally created by intervertebral disc height between two vertebral bodies. These passageways are at the left and right sides of the disc.
Purpose of the Spinal Cord and Nerves
The brain and the spinal cord make up the central nervous system, or CNS. Nerve roots branch outward through neuroforamen into the body forming the peripheral nervous system, or PNS. Nerve roots innervate, stimulate sensation, feeling, and function, movement.
- Brain Stem: It connects the brain and spinal cord.
- Spinal Cord: Carries nerve impulses to and from the brain.
Spinal Nerve Root Regions
| Region | Number | Area Innervated |
| Cervical | 8 pair | Head, neck, shoulders, arms, hands |
| Thoracic | 12 pair | Upper abdomen, chest, and back muscles |
| Lumbar | 5 pair | Lower back and legs |
| Sacral | 5 pair | Buttocks, legs, feet, and anal and genital areas |
Dermatomes
Sometimes a spinal condition causes a specific area of the skin’s surface to feel pain, numbness, or tingling sensations. The skin sensation originates from a single spinal nerve root. Another name for the area of skin sensation is dermatome.
Dermatome patterns can help medical providers understand whether symptoms may be related to a specific spinal nerve root. For example, nerve irritation in the neck may contribute to symptoms into the shoulder, arm, or hand, while nerve irritation in the lower back may contribute to symptoms into the buttock, leg, or foot.
Related Spine and Nerve Conditions
Spinal nerve irritation may be associated with several pain conditions, including cervical radiculopathy, lumbar radiculopathy, sciatica, disc herniation, or spinal stenosis.
When to Seek Evaluation
Newark Rehabilitation Center can help patients better understand back and/or neck pain. Our doctors diagnose the cause of pain and welcome the opportunity to recommend appropriate non-surgical and surgical treatment options to help patients manage their condition.