| | The Spinal Cord is part of the Central Nervous System and is connected to the brain. From the brain the cord runs down the back and is surrounded and protected by the bony vertebral column. The cord is surrounded by fluid called "Cerebral Spinal Fluid" that acts as a cushion to protect the delicate nerve tissues.
The cord itself consists of millions of nerve fibers that transmit information to and from the limbs, trunk and organs of the body. Nerves called the spinal nerves or nerve roots come off the spinal cord and pass out between the vertebrae to carry the information from the spinal cord to the rest of the body.
| | | | What is 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 the 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. |
Complete or Incomplete | Spinal cord injuries are classified as either complete or incomplete.
An incomplete injury means that the ability of the spinal cord to convey messages to or from the brain is not completely lost. People with incomplete injuries retain some motor or sensory function below the injury.
A complete injury is indicated by a total lack of sensory and motor function below the level of injury, no sensation and no voluntary movement. Both sides of the body are equally affected.
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Level of Injury (Lesion) | The level of injury is the exact point in the spinal cord at which damage has occurred. The levels are determined by counting the nerves from the top of the neck downwards, and these nerves are grouped into four different areas, Cervical, Thoracic, Lumbar and Sacral.
When both legs are paralysed it is referred to as paraplegia or paraparesis. Paralysis of all four limbs is referred to as tetraplegia or quadriplegia.
C-5 injuries often result in shoulder and biceps control, but no control at the wrist or hand. C-6 injuries generally yield wrist control, but no hand function. Individuals with C-7 and T-1 injuries can straighten their arms but still may have dexterity problems with the hand and fingers.
The level of the spinal cord segments do not relate exactly to the level of the vertebral bodies i.e. damage to the bone at a particular level e.g. L5 vertebrae does not necessarily mean damage to the spinal cord at the same level. This is because there are: 7 cervical vertebrae but 8 cervical nerve roots leaving the cord.
Besides a loss of sensation or motor functioning, individuals with SCI also experience other changes. For example, they may experience dysfunction of the bowel and bladder.
Other effects of SCI may include low blood pressure, inability to regulate bood pressure effectively, reduced control of body temperature, inability to sewat below the level of injury, and chronic pain.
C = Cervical (Neck) C1-C7
A cervical spinal cord injury would result in Quadraplegia / Tetraplegia. Cervical nerves (nerves in the neck) supply movement and feeling to the arms, neck and upper trunk.
Very high injuries (C1, C2) can result in a loss of many involuntary functions including the ability to breath, necessitating breathing aids such as mechanical ventilators or diaphragmatic pacemakers.
T = Thoracic T1-T12
Thoracic Injuries at the thoracic level and below result in paraplegia, with the hands not affected. At T-1 to T-8 there is most often control of the hands, but poor trunk control as the result of lack of abdominal muscle control. Lower T-injuries (T-9 to T-12) allow good trunk control and good abdominal muscle control. Sitting balance is very good.
L = Lumbar L1-L5
Lumbar and sacral nerves (from the lower back) supply the legs, the bladder, bowel and sexual organs. Injuries at this level can yield some control of the hip flexors and legs.
S = Sacral S1-S5
The sacral vertebrae are fused to make up the sacrum. May be able to walk using short leg braces. Incontinence can sometimes be a problem.
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Cauda Equina Lesion | The Cauda Equina is the mass of nerves which fan out of the spinal cord at between the second Lumbar regions of the spine. The spinal cord ends at L1 and L2 at which point a bundle of verves travel through the Lumbar and Sacral vertebrae. Injury to these nerves will cause partial or complete loss of move sensation. It is possible, if the nerves are not too badly damaged, for them to grow again.
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