What is a Spinal Cord Injury?
Spinal Cord Injury Glossary
The spinal cord is the major collection of nerves that communicate muscle movement and sensation to and from the brain and the rest of the body. It is surrounded by a column of bony rings called vertebrae. The nerves that travel from the brain to the tailbone, together with this column of bones is called the spine.
An injury to the spine may cause the bones around the spinal cord to break and press against the spinal cord, which can damage the nerves, breaking the communication path and affecting movement and sensation.
Damage to the spinal cord and nerves can also occur without damage to the bones, such as with a disease of the spinal cord.
The amount of the loss of body function following injury or disease to the spinal cord depends on the level and "completeness" of the injury. The completeness of the injury refers to the amount of messages that are getting through the spinal cord. If someone is without any feeling or movement below his/her injury, it is called a “complete” injury. If someone has some feeling or movement well below his or her injury, it is an “incomplete” injury.
In addition to movement and sensation, the spinal cord carries nerves signals that affect and control other body systems such as skin, bowel, bladder, and breathing. So, damage to the spinal cord, depending on the completeness of the injury, may cause these body functions not to work the same as before.
See also “cervical,” “thoracic,” and “lumbar spine” below.
Other terms related to the spinal cord and spinal cord injury:
- Anterior Cord Syndrome – Condition affecting front-facing part of spinal cord causing loss of muscle control and sensitivity to pain and temperature, while proprioception (see below) is preserved.
- Autonomic Dysreflexia (also known as autonomic hyperreflexia or “going hyper”) – Uncontrolled nervous system response below the level of injury, occurring with spinal cord injury above the 6th thoracic vertebra (see “thoracic spine”), resulting in abnormally high blood pressure, headache, sweating above the level of injury, loss of bowel and bladder control, goosebumps, and chills/fever. Considered a medical emergency if untreated.
- ASIA Impairment Scale (AIS) – The American Spinal Injury Association’s (ASIA) system of neurological classification is the most commonly accepted evaluation of impairment for spinal cord injury used by health care professionals.
In an incomplete injury, the spinal cord’s ability to send messages to or from the brain is not completely lost, and thus some muscle control or sensory function is retained below the injury.
A complete injury causes a total lack of sensory and muscle control below the level of injury.
- Brown-Séquard Syndrome – Condition where the spinal cord is cut, causing loss of ability to move and to perceive body position on one side of the body, while losing sensitivity to pain and temperature on the other side.
- Cauda Equina Syndrome – Involves injury to the lumbosacral nerve (the lower end of the spinal cord), leading to bladder and bowel incontinence and paralysis of the legs. Usually caused by a severely ruptured disk in the lumbar spine.
- Central Cord Syndrome – An injury involving the central part of the neck area of the spinal cord resulting in greater weakness in the arms than in the legs with sacral sensory sparing (see below).
- Cervical Spine – The seven bones or vertebrae of the spine in the neck (numbered C1 through C7 from the top)
- Disk – Spinal disks are flat, circular, rubbery pads embedded between each vertebra that serve to protect the spinal cord and as shock absorbers for the spine, becoming harder and less elastic with age.
- Lumbar Spine – The five bones or vertebrae of the spine in the lower back (numbered L1 through L5 from the top)
- Paraplegia – Injury to the thoracic, lumbar, or sacral level of the spinal cord, resulting in paralysis of the legs
- Proprioception – Ability to perceive the position and movement of one’s body parts
- Quadriplegia – Injuries at the cervical (neck) level of the spinal cord resulting in paralysis of the arms and legs (more commonly referred to as tetraplegia).
- Sacrum or sacral segments – Triangular bone at the base of the lumbar (lower back) spine (numbered S1 through S5) right above the coccyx or tailbone
- Sacral Sparing – Sensory or motor function at the anal mucocutaneous junction, meaning the patient still has the ability to constrict the anal sphincter and control bowel movements
- Spinal Shock – Often occurring soon after spinal cord injury, a loss of reflexes below the level of injury with loss of sensation and muscle control. This condition can last for several hours to days after initial injury.
- Tetraplegia – (The more commonly used term for quadriplegia) Injury to the spinal cord in the cervical region (neck) with resulting loss of muscle strength in both arms and legs.
- Thoracic Spine – The 12 bones or vertebrae of the spine in the area of the chest (numbered T1 through T12 from the top)