The two main types of SCIs are complete and incomplete. A complete injury causes a total loss of sensation and movement below the level of the injury. An incomplete injury causes partial loss of sensation and movement below the level of the injury because only part of the spinal cord or nerves have been damaged.

Complete Spinal Cord Injury
A complete SCI is least likely to get better.
There is no function below the level of injury:
- No movement
- No sharp/dull feeling
- No hot/cold feeling
- No vibration sensation
- No feeling of light or deep touch
- No sense of position of the arms or legs
Incomplete Spinal Cord Injury
The three main types of incomplete injuries are: anterior cord syndrome, central cord syndrome, and Brown-Séquard syndrome.

Anterior cord syndrome:
This happens when the front part of the spinal cord is damaged. It causes loss of movement and loss of sharp/dull and hot/cold feelings below the level of injury. A person still has the sense of position of the arms and legs, vibration, and sense of light/deep.
It is caused by acute disc herniations, tumors, and when the head is forced to the chest (cervical flexion).

Central cord syndrome:
This happens when the middle part of the spinal cord is damaged. It causes more loss of movement and sensation in the arms than in the legs.
It is caused by a hyperextension injury (when the head is forced backward). It also can be due to degenerative bone changes in the spine and/or narrowing of the spinal canal that surrounds the spinal cord.

Brown-Séquard syndrome:
This happens when one-half of the spinal cord is damaged. It causes one side of the body to be stronger than the other side below the level of injury. The side of the body that is weaker is able to feel sensations of hot/cold and sharp/dull better than the other side of the body. The strength and sensations differ based on the degree of damage to the spinal cord.
It can happen from bullet or knife wound injuries, and rarely with acute ruptured discs.