Levels of paralysis (functional)
Because the spinal-cord is arranged in a hierarchical order from where it exits this skull all the way down to the base of the spine, it is possible to estimate the level of spinal cord injury according to any change in either sensory or motor function in the injured person.
The cervical vertebrae are numbered C1 through to C7, and the nerves which exit from the spinal-cord at these levels are similarly numbered, with the C1 nerve root exiting above the C1 vertebrae and the C7 nerve root exiting above the C7 vertebrae. The C8 nerve root exits below the C7 vertebraand from that point onwards each of the nerves corresponding to T2 to T12, L1 to L5 and S1 to S5 exits below the corresponding vertebra.
By recognising the function (motor and sensory) corresponding to each of these spinal nerves, and noting any change from normal, the “level” of the spinal cord injury can be determined.
The level of injury and remaining function is important long-term if there is permanent damage for things like bowel and bladder control, ability to use a wheelchair etc.