Overview of Spinal Cord Injury

Spinal cord injury is a serious condition that affects lives dramatically. The spinal cord is a column that runs from the base of the brain to the lower back. With the brain, it makes up the central nervous system.

The spinal cord is critical for sending messages to and from the brain and other parts of the body. Important body functions like breathing, digestion, movement, and elimination are all associated with nerves of the spinal cord.

The spinal cord is protected by 33 bones called vertebrae, which are stacked one on top of the other. Messages between the brain and other parts of the body travel along pathways, called axons, which branch out from the spinal cord to other areas. Axons are long fibers of nerve cells (neurons) that carry outgoing messages.

The spinal cord often is injured when vertebrae are broken or fractured and axons are damaged. Damage prevents messages from getting through, causing a number of problems. Bleeding, swelling, and the body's chemical responses contribute to waves of additional damage that can continue for days or even weeks following the injury.

Much of the prognosis and recovery depends on the location and severity of the injury. Some patients recover well and others may be paralyzed for life. Generally, patients experience more paralysis when the injury is higher in the spinal column.

If a patient loses function in all 4 limbs, the condition is called quadriplegia or tetraplegia. Paraplegia occurs when function is lost in the lower body only.

Spinal Cord Injury Types

Spinal cord injuries are termed complete or incomplete (also called partial) depending on how much of the spinal cord has been damaged. With a complete injury, messages cannot travel to and from the brain and there is no feeling or movement below the injury. An incomplete injury is less severe. This type of spinal cord injury allows for some messages to get through and for limited sensory and motor ability.

Injuries can also be classified as traumatic or nontraumatic. Traumatic injuries are sudden, often from a strong force that causes immediate damage. Nontraumatic injuries tend to develop more slowly from diseases (e.g., arthritis, cancer), bleeding, infections, or the degeneration of vertebrae.

Incidence and Prevalence of Spinal Cord Injury

According to the Spinal Cord Injury Information Network (August 2014), approximately 12,500 people suffer spinal cord injuries in the United States each year and about 276,000 people in the United States are currently living with such injuries. Approximately 52 percent of spinal cord injuries result in quadriplegia or tetraplegia and about 42 percent result in paraplegia.

Publication Review By: Alan B. Ettinger, M.D.

Published: 14 Feb 2007

Last Modified: 06 Oct 2015