Spinal Cord Injury

A spinal cord injury (SCI) happens when there’s damage to your spinal cord, a thick bundle of nerve fibers that allows your brain to communicate with other nerves almost everywhere else in your body. These injuries can range from minor and manageable to severe and permanent.

The spinal cord is one of the two components of your central nervous system (CNS). Your nervous system is like a multilane expressway to and from your brain, the other component of the CNS. It has lanes for traffic leaving your brain and other lanes for traffic heading to your brain.

Your spinal cord connects to your spinal nerves, which are like on- and off-ramps that connect to peripheral nerves that branch out everywhere else in your body. Nerve signals are the cars that travel this expressway and use those on- and off-ramps.

Spinal cord injuries are like closures that affect the lanes in this expressway. But unlike a real-life expressway, the spinal cord has no detours. The traffic that uses the closed lanes can’t reach where it’s going. If the damage is severe enough, the closure might be permanent. That’s what causes paralysis and other severe SCI injury symptoms.

Types of this condition

There are two ways that experts organize the types of spinal cord injuries: By the way the injury affects your spinal cord and where in your spinal cord the injury happens. An SCI can interrupt nerve signal traffic going to and coming from anywhere below where it happens.

By location

• Cervical spine: This section is in your neck. It goes from the bottom of your skull to about the same level as your shoulders.
• Thoracic spine: This section stretches from your upper back to just below your navel (belly button).
• Lumbar spine: This section is in your lower back. It extends about to the top of where your buttocks meet, but your spinal cord ends a couple of inches above that.
• Sacral spine: This section is in your back. It contains nerve roots below your butt to your tailbone.

By severity

• Incomplete: An incomplete SCI is like a closure that only affects some lanes. Others remain open, so some abilities below the injury remain intact.
• Complete: A complete SCI affects all the lanes. No traffic gets through. It usually means permanent loss of all abilities below the injury, including paralysis.

Your spinal cord has 31 segments (they line up with the 31 pairs of spinal nerves). Experts use letter-number combinations to designate them. The letter indicates the section of the spine, and the number indicates the segment. For example, C8 means the cervical spinal cord’s eighth (and lowermost) segment.

SCIs also commonly involve multiple phases. The first phase is the initial injury. But in the following hours and days, a secondary injury can also develop, causing swelling and further damage to your spinal cord.

How common are spinal cord injuries?

Spinal cord injuries are uncommon. Between 250,000 and 500,000 happen every year worldwide.

In the United States, there are about 18,000 new traumatic SCI cases each year. About 78% of people with a new SCI are assigned male at birth. The average age at the time of injury is 43.