Containing more than 20 million nerve fibers, it is the major conduit for transmitting motor and sensory information between brain and body. It runs vertically within the spinal column, composed of 33 vertebrae separated by rubbery disks. The nerve signals that travel the spinal cord help regulate sensation, movement, and bodily functions, such as bladder control. Axons transmit nerve signals from cell to cell, so when they're destroyed the cells can't communicate, causing loss of functions controlled by the affected cells. Spinal cord injury affects a number of body functions.
Bladder control is usually impaired, and sometimes completely destroyed.
Some people retain involuntary reflexes that help empty the bladder, but others have completely flaccid bladder muscles. Urine left in the bladder breeds infection, which can become chronic and cause kidney damage. Bowel management is another challenge, since messages from brain to bowel to empty don't get through, and anal sphincter muscle control is lost. Then there are skin problems like bedsores, common to wheelchair patients. Paraplegia results from damage done to the thoracic, lumbar or sacral regions of the spinal cord.