Damage to the spinal cord is a very complex injury. This article describes the basic anatomy of the spinal cord and provides information on types of spinal cord injury.
The Spinal Cord
The spinal cord is a bundle of nerves that connects the brain to the body. It begins at the base of the brain and extends approximately 18 inches to waist level. The nerves in the spinal cord send messages from the brain to other parts of the body, controlling movement, sensation, and feeling. The spinal cord also controls involuntary activities such as breathing, body temperature, blood pressure, and sweating.
The vertebrae, or backbones, are rings of bone stacked on top of each other. Vertebrae surround and protect the spinal cord. The backbone, or spinal column, is divided into four sections. The spinal column begins at the neck with the seven cervical vertebrae. The next section corresponds with the chest and is made up of the twelve thoracic vertebrae. Further down the back is the lumbar area, with five vertebrae. The bottom of the spinal column consists of the five sacral vertebrae. Each vertebra is named according to its location. The top vertebra, for example, is the first vertebra in the cervical section and is called the C-1. The next vertebra is called C-2, and so on. The thoracic area begins with the T-1 vertebra, where the top rib attaches. The lumbar and sacral portions of the spinal column are named the same way (L-1, S-1, etc.).
Causes of Spinal Cord Injury
When the spinal cord is injured due to trauma, it is usually because the bones of the spinal column are pinching the spinal cord. When the bone compresses the nerves in the spinal cord, bruising or swelling occurs. The spinal cord may even be torn as a result of the trauma. After the initial injury, the damage to the spinal cord may worsen due to responses in the body that cause swelling, inflammation, and free radicals. The sooner the spinal cord is decompressed—relieved of the pressure caused by displaced bone—the better. Other early measures that can be used to prevent complications include traction or surgery to decompress the spinal cord and methylprednisone therapy. Methylprednisone is a high-dose steroid that can improve neurological recovery by 20%. However, methylprednisone must be administered within eight hours of the injury to be effective.
After the initial injury to the spinal cord, the swelling may go down and nerves may begin to function again. There is currently no way to accurately predict what nerves, if any, will work again. Twitching and shaking is also common after a spinal cord injury. However, these spasms are not a sign of recovery. They are often a result of mixed messages from the injured nerves in the spinal cord.
In the first hours after a spinal cord injury, there are several important questions to ask your doctor:
- Was methylprednisone given?
- What is the level of the injury?
- Has the spinal cord been decompressed?
- Have blood thinners been given to prevent dangerous clots?
- Are the lungs, skin, and bladder being properly cared for to prevent complications?
Types of Injury
Spinal cord injuries are described by the location on the spinal column. For example, a person who is injured at the C-3 vertebra (the third vertebra in the cervical area) will have a C-3 injury. Generally, the higher on the spinal column an injury occurs, the more severe the results. A person who sustains a C-1 to T-1 injury is usually described as having tetraplegia, also known as quadriplegia. The person can experience loss of feeling and/or movement in the head, neck, shoulder, arms, and/or upper chest. People with injuries above the C-4 level may require a ventilator in order to breathe. Paraplegia is the term used to describe the condition of a person who has injury at the T-2 to S-5 level. A paraplegic experiences loss of movement and/or feeling in the chest, stomach, hips, legs and/or feet. Paraplegia as a result of a T-2 to T-8 level injury often involves control of the hands but a lack of control of the abdominal muscle. Injuries to the lower part of the thoracic area, T-9 to T-12 injuries, result in good control of the trunk area but little or no control of the legs. Injuries at the lumbar and sacral levels result in decreased control of the hip flexors and legs.
Spinal cord injuries are also classified according to whether they are “complete” or “incomplete.” If an injury is complete, then there is no functioning below the level of the injury. For example, a person with a T-12 level injury would have a complete injury if he had no functioning of his leg muscles, bowel, bladder, or sexual function—these are controlled by spinal cord nerves below the T-12 level. If a spinal cord injury is incomplete, there is some movement or feeling below the level of injury. Each patient varies as to the degree of functioning below the level of injury. People with incomplete injuries have a greater chance of recovering some or all movement and feeling.
In addition to movement and feeling, spinal cord injuries also affect other bodily functions. Nerves in the spinal cord are responsible for bowel, bladder, and sexual functions. People with spinal cord injuries must learn new ways to manage these functions. For example, catheters are used in order for the person to properly eliminate urine because spinal cord injuries paralyze the bladder. Patients must also pay special attention to respiratory and skin problems that result from spinal cord injuries.
Read the next article: Spinal Cord Injury Treatment and Rehabilitation