Spinal cord injuries result from damage to the vertebrae, ligaments or disks of the spinal column or to the spinal cord itself. A traumatic spinal cord injury may stem from a sudden, traumatic blow to your spine that fractures, dislocates, crushes or compresses one or more of your vertebrae. It also may result from a gunshot or knife wound that penetrates and cuts your spinal cord. Additional damage usually occurs over days or weeks because of bleeding, swelling, inflammation and fluid accumulation in and around your spinal cord.

A nontraumatic spinal cord injury may be caused by arthritis, cancer, inflammation, infections, or disk degeneration of the spine.

Your brain and central nervous system

The central nervous system comprises the brain and spinal cord. The spinal cord, made of soft tissue and surrounded by bones (vertebrae), extends downward from the base of your brain and is made up of nerve cells and groups of nerves called tracts, which go to different parts of your body. The lower end of your spinal cord stops a little above your waist in the region called the conus medullaris. Below this region is a group of nerve roots called the cauda equina.

Tracts in your spinal cord carry messages between the brain and the rest of the body. Motor tracts carry signals from the brain to control muscle movement. Sensory tracts carry signals from body parts to the brain relating to heat, cold, pressure, pain and the position of your limbs.

Damage to nerve fibers

Whether the cause is traumatic or nontraumatic, the damage affects the nerve fibers passing through the injured area and may impair part or all of your corresponding muscles and nerves below the injury site. A chest (thoracic) or lower back (lumbar) injury can affect your torso, legs, bowel and bladder control, and sexual function. In addition, a neck (cervical) injury affects movements of your arms and, possibly, your ability to breathe.

Common causes of spinal cord injury

The most common causes of spinal cord injuries in the United States are:

  • Motor vehicle accidents. Auto and motorcycle accidents are the leading cause of spinal cord injuries, accounting for more than 40 percent of new spinal cord injuries each year.
  • Falls. Spinal cord injury after age 65 is most often caused by a fall. Overall, falls cause more than one-quarter of spinal cord injuries.
  • Acts of violence. As many as 15 percent of spinal cord injuries result from violent encounters, often involving gunshot and knife wounds, according to the National Institute of Neurological Disorders and Stroke.
  • Sports and recreation injuries. Athletic activities, such as impact sports and diving in shallow water, cause about 8 percent of spinal cord injuries.
  • Alcohol. Alcohol use is a factor in about 1 out of every 4 spinal cord injuries.
  • Diseases. Cancer, arthritis, osteoporosis and inflammation of the spinal cord also can cause spinal cord injuries.
Oct. 22, 2011

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