What are the types &
effects of SCIs?
The two main types of spinal injury are known as 'complete', and 'incomplete'. This page has information on both of these types.
A post-injury swelling known as ‘spinal shock’ means that it is not easy to determine which one has been suffered. It usually takes 6 to 8 weeks for the swelling to reduce, and for the injury type to be determined.
Complete spinal cord injury
Of the two main types, a complete spinal cord injury is the most severe.
In such cases, there is sufficient trauma to cause damage across the whole width of the spinal cord resulting in a complete and permanent loss of function and sensation below the level of injury.
Depending on where the site of injury is, the eventual condition is known as either complete paraplegia or complete tetraplegia.
Generally, complete paraplegia is the result of complete damage to the spinal cord anywhere below the neck.
Specifically this is caused by injury to the cord in the spinal column’s middle section, known as the thoracic region, or further below this in what are known as the lumbar and sacral regions.
This injury causes a complete loss of movement and feeling in the legs and in some circumstances the trunk, whilst normal use of the arms will continue.
The extent of this paralysis is affected by the site of the injury to the spinal cord, which in turn determines how the injury is classified. In the thoracic region, the first vertebra (bone) beneath the neck is called the T1, beneath this the T2 and so on down to T12. So for example, complete injury to spinal nerves at the T4 bone is known as T4 paraplegia.
The same applies below this in the lumbar region, where the first vertebra is called the L1 running downwards to L5, and then below this again in the sacral region (S1 to S5). For example, following the same system a complete injury to the spine at the L2 region is known as L2 paraplegia and so forth.
This classification system shows that the higher up the spine a complete injury occurs, the more severe the loss of function and sensation is in the lower body.
Complete tetraplegia is the most extreme level of paralysis, where there is loss of function and sensation in the arms, body and legs.
This happens after there has been severe injury to the spinal cord in the neck, also known as the cervical region. Depending on which part of the cord has sustained complete damage, the extent of arm paralysis will vary and this dictates how the injury is classified.
There are eight levels of complete tetraplegia, and each one refers to where the spine has been injured in relation to eight nerves that are protected by seven vertebrae in the neck. Each nerve is numbered in order; starting with C1, being closest to the skull and then continuing down the spine to C8, hence if the site of complete injury is at C4 it is known as C4 Tetraplegia.
The higher the site of injury to the spinal cord in the neck, the more severe the loss of function and sensation in the entire body.
Incomplete spinal cord injuries are much more common.
In such cases, areas of the spinal cord remain intact meaning that rather than a complete loss of function, some limited mobility or sensation (or both) will remain.
If spinal shock has occurred, the symptoms exhibited immediately post-injury may appear to be those related to complete paralysis. However, a small amount of movement may return at any time without any feeling, or alternatively some feeling may return but with little or no mobility.
Incomplete spinal cord injuries vary greatly from case to case because of the many ways in which the spine can be damaged, the different parts of the cord that can be affected, and the force of impact that caused the injury.
However, there are five main categories of incomplete spinal cord injury:
Anterior cord syndrome: Injury to the front of the spinal cord.
Central cord syndrome: Injury to the centre of the spinal cord.
Posterior cord syndrome: Injury to the back of the spinal cord.
Brown-Sequard syndrome: Injury to the one side of the spinal cord.
Cauda equina syndrome: This final category of injury is one to a group of nerves in the lower region of the spine.
A variety of treatment methods are available to people who have a spinal cord injury. To learn more, please visit our spinal injury rehabilitation section.