The effects of SCI depend on the type of injury and the level of the injury. SCI can be divided into two types of injury - complete and incomplete. A complete injury means that there is no function below the level of the injury; no sensation and no voluntary movement. Both sides of the body are equally affected. An incomplete injury means that there is some functioning below the primary level of the injury. A person with an incomplete injury may be able to move one limb more than another, may be able to feel parts of the body that cannot be moved, or may have more functioning on one side of the body than the other. With the advances in acute treatment of SCI, incomplete injuries are becoming more common.

Paralysis also has other effects as well as a loss of sensation or motor functioning Individuals with SCI also experience other neurological changes. For example, the person may experience dysfunction of the bowel and bladder,. Sexual functioning is frequently affected in men with SCI, as they may have their fertility affected, while women's fertility is generally not affected. High spinal injuries injuries (C-1, C-2) can result in a loss of many involuntary bodily functions, including the ability to breathe. Breathing aids such as mechanical ventilators or diaphragmatic pacemakers may be needed to regulate a persons breathing in these cases. Other effects of SCI may include low postural blood pressure (Postural Hypotension), inability to regulate blood pressure effectively , reduced control of body temperature (poikilothermic), inability to sweat below the level of injury, and chronic pain.