What is a severed Spinal Cord Injury?

A spinal cord injury usually begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. The damage begins at the moment of injury when displaced bone fragments, disc material, or ligaments bruise or tear into spinal cord tissue. Most injuries to the spinal cord don't completely sever it. Instead, an injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy axons -- extensions of nerve cells that carry signals up and down the spinal cord between the brain and the rest of the body. An injury to the spinal cord can damage a few, many, or almost all of these axons. Some injuries will allow almost complete recovery. Others will result in complete paralysis.
The spinal cord is divided into segments which control different parts of the body. The upper segments regulate movement and sensation in the upper body, while the lower part sends signals the lower body. A cord that is completely cut in one area causes total paralysis in the part of the body linked to that segment. If the spinal cord is partially severed, some feeling and movement may be possible. Injury to the specific section of the spinal cord that controls breathing can cause death.
Car accidents account for about half of all severed spinal cords. Sporting mishaps, falls, and some diseases can also cause permanent damage to the spinal cord. More than 75% of all victims who suffer from a severed spinal cord are young, male adults. The accidents are often linked to risky behavior, such as diving into shallow water, accidents while not wearing a seat belt, and drinking while driving. Emergency workers who respond to these accidents routinely strap patients to a backboard to prevent further damage whenever a spinal cord injury is suspected.
People with a severed spinal cord face a number of complications linked to their inability to move. Deep vein thrombosis can occur from the lack of normal blood flow to parts of the body. Blood pools in the veins and can cause clots, pressure sores, joint problems, and urinary trouble. Men who are paralyzed below the waist are usually unable to perform sexually, but a woman may still be able to become pregnant and deliver a healthy child under close medical supervision.

Cells in the spinal cord do not regenerate like the cells in the skin, blood, muscle, and some other organs do. When a spinal cord is totally severed, the damage is usually permanent. Patients require long-term rehabilitation to learn how to deal with the condition and gain as much function as possible. Clinical trials began in 2010 using embryonic stem cells to treat patients with a severed spinal cord after years of studies on animals.