When a person suffers from a sudden blow to the spine, that person may suffer a broken neck or broken back. These injuries may result in a spinal cord injury, or SCI, where there is damage to the spinal nerves as a result of the trauma.

As of 2005, over 40 percent of spinal cord injuries in the United States were caused by car accidents and approximately 27 percent were caused by falls. The rest of the injuries were caused by violence, sport-related accidents and other unknown causes.

A spinal cord injury is defined by its level, severity and type. The level has to do with the location of the injury, as in the name and number of the vertebrae at the injury site. There are seven cervical vertebrae, C1 through C7, in the neck, and 12 thoracic vertebrae in the upper back, T1 through T12. There are also five lumbar vertebrae, L1 to L5, in the lower back, five sacral vertebrae which form the sacrum and four vertebrae of the coccyx, or tailbone.

The severity of a SCI can fall under two categories: complete injury or incomplete injury. A complete injury requires that all sensory function and motor function be lost below the area of the SCI. An incomplete injury allows for some sensory or motor function below the damaged area.

As far as type goes, a SCI can fall under tetraplegia or paraplegia. Tetraplegia refers to a spinal injury that occurs anywhere from C1 vertebra to T1. The symptoms of such an injury can involve loss of sensation or movement in the head, neck, shoulders, arms, upper chest, hands, legs, or pelvic organs. Paraplegia, on the other hand, typically involves injury from T2 down to S5. This means that the person is unable to move the lower parts of the body. The chest, stomach, hips, legs and feet may all be affected. The closer a spinal injury is to the skull, the higher the risk for serious damage. Spinal cord injuries can result in permanent disability or paralysis.

Source: NIH, “Spinal Cord Injury (SCI): Condition Information,” accessed on Nov. 23, 2015