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Anatomy of the Spinal Cord

The spinal cord is part of the central nervous system. This helps control the sense of feeling, movement, and functioning of the body's internal organs. Made up of bundles of nerves, the spinal cord carries signals from your body to your brain, and vice versa. 

The spinal cord is tube-shaped and extends from the brain all the way down to the lumbar, or lower, region of the spine. Branching off from the spinal cord are small nerves, called nerve roots. These roots emerge from small spaces between the vertebrae (the bones that surround the spinal cord) and run to various parts of the body.

The entire spinal cord is surrounded by a liquid called cerebrospinal fluid (commonly referred to as CSF). The fluid protects the spinal cord from injury. The spinal cord is also protected by 3 layers of coverings called the meninges—the dura mater, the arachnoid mater, and the pia mater.

The spinal cord and spine are divided into 4 regions. Damage to the nerves in the spinal cord can result in various medical conditions, depending on the region that is affected.

Anatomy of the spinal cord
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Cervical region

This portion of the spinal cord contains nerve roots that connect to the upper body, arms, and hands. Between the vertebrae in the spine are spongy cushions called intervertebral disks. If the disks collapse, they may "pinch" the nerves in the cervical spine, leading to a condition called cervical radiculopathy. This condition can cause pain, weakness, or numbness in the arms. If the cervical region of the spinal cord is severely injured, as from a fall, it can cause quadriplegia, a condition in which most of the body is paralyzed.

Thoracic region

The nerve roots in the thoracic spine run to the chest and stomach and control movement in those portions of the body. Serious injuries to the thoracic region of the spinal cord can lead to paraplegia, a paralyzation of the lower portion of the body.

Lumbar region

The lumbar spine is the lower region of the back. Nerve roots coming from the spinal cord in the lumbar spine control the legs, bladder, and bowel. The lumbar region is where the spinal cord ends. It continues as a bundle of nerve roots in the lower back, known as the cauda equina. If an intervertebral disk in the lumbar spine herniates or moves into the space containing a nerve root, lower back pain, or lower extremity pain can result. This is known as lumbar radiculopathy. In severe cases, it can cause cauda equina syndrome, a serious condition that compresses the nerve roots and results in urinary retention, loss of sensation in the groin (saddle anesthesia), and weakness or paralysis of the legs and/or feet. 

Sacral region

The lowest part of the spine contains 5 pairs of nerves, which control the thighs, lower legs, and the genital and anal areas. Sacral nerve injury can happen when the bones in the sacral region become fractured. This can lead to lower back pain, urinary incontinence or retention, loss of feeling in the foot, and even sexual dysfunction. 

Maintaining a healthy spinal cord

Although some spinal cord injuries, like those from car accidents, can't always be avoided, you can take many steps to preserve the health of your spine and the spinal cord nerves within it. Injuries as the result of a car accident may be reduced with the proper use of seat belts and air bags. Maintaining or attaining a healthy weight is suggested because excess pounds can put unnecessary stress on your back. It is also important to maintain good posture and participate in physical activities that strengthen your back muscles. To strengthen the bones of your spine, a calcium-rich diet is also essential. Finally, know your limits and avoid picking up items that are too heavy for you to lift safely. 

Online Medical Reviewer: Freeborn, Donna, PhD, CNM, FNP
Online Medical Reviewer: Jasmin, Luc, MD
Date Last Reviewed: 8/24/2015
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