SPINAL & SPINAL CORD INJURIES
What
and Why?
Spinal
injury and spinal cord injury results when the body is exposed to
forces greater than body parts can withstand. Force in amounts that
can cause such damage result from auto crashes, falls from heights,
falls, crashes and blows associated with sport and recreation, contact
with an unmovable object or surface when diving or, from penetration
by gunshot or sharp objects.
Spinal
Injury
Sometimes only the bony structures and/or ligaments are damaged, resulting
in various kinds of fractures (broken bones and discs or dislocations)
and an unstable spine. Though the area affected will probably need
to be immobilized until healing results, the spinal cord is not affected.
Spinal Cord Injury
When the injury involves the spinal cord, the flow of messages between the brain
and the rest of the body is interrupted or broken. The interruption results in
a decrease or loss in motor function (movement) or sensation (feeling) or both
below the level of injury and will also affect bowel, bladder and sexual function.
Testimonials
The
Spine and Spinal Cord
The Spine
The spine or backbone gives the body stability and protects the spinal cord.
It is a flexible column made up of 33 vertebrae (spinal bones).
Through the centre of this column, is a narrow canal where the spinal cord is
located.
The column is made flexible by the discs (spongy shock absorbers) located between
each vertebra, and the ligaments made of tough elastic fibers, which hold the
vertebrae together.
The Vertebrae are Separated into Groups:
- 7 cervical (neck) C1-C7
- 12 thoracic (chest)
T1-T12
- 5 lumbar (lower back)
L1-L5
- 5 sacral S1-S5 fused
- 4 coccyx (tailbone)
fused
The Vertebral Body
The shape of each vertebra (bone)
that makes up the column varies slightly depending on its location.
In general each vertebra is composed of a body and an arch from which
several fingers of bone (processes) extend.
The Spinal Cord
The spinal cord, located within the spinal canal, is a delicate tube
of nerve cells and nerve fibers that extends from the brain to
the lower back. It then branches into a sheaf of nerves called
the cauda equina or horse's tail which extends to the coccyx. The
spinal cord is composed of 31 functional segments, with a pair
of spinal nerves attached at each segment.
The cord is encased in a tough fibrous membrane (dura mater) and is bathed in
a fluid (cerebral-spinal fluid) which provides further protection. Several arteries
supply the cord with blood.
Together, the brain and the spinal cord make up the central nervous system. The
function of the spinal cord is to relay messages (nerve impulses) from the brain
to the body and from the body to the brain. All movements of the body and limbs
and all sensation are relayed through the spinal cord. Injury to the cord results
in an interruption in the ability to relay these messages.
Within the cord, nerve fibres are arranged in bundles or tracks, each of which
controls a different function (motor or sensory functions). A number of important
reflexes such as bladder and bowel control, sexual function and tendon reflexes
are controlled through the spinal cord as well.
Motor messages, carried on motor nerves, involve voluntary movement, such as
moving an arm or a leg.
Sensory messages, carried on sensory nerves, indicate temperature, pain, touch,
and vibration.
The spinal cord also plays a
part in the transmission of messages from the autonomic nervous system.
The spinal nerves, which attach to the cord at the nerve roots, provide
pathways for the involuntary functions (meaning without your conscious
control) of the autonomic nervous system. The autonomic nervous system
has two divisions, the sympathetic and the parasympathetic. Together,
they regulate many of the body functions that we are mostly unaware
of - for example, heart beat, maintenance of blood pressure, muscle
tone, temperature regulation, bladder emptying, sexual functioning.
An imbalance of the divisions of the autonomic nervous system, which
happens with some spinal cord injuries, can disturb circulation,
blood pressure control and bowel, bladder and sexual function.
Complete and Incomplete Injuries
Injuries to the spinal cord are called
complete or incomplete to describe the degree of interruption in the transmission
of messages.
A complete injury means that there is no transmission (delivery) of messages
beyond the level of injury, resulting in no sensation and no voluntary movement
below this area.
A complete injury also implies that there is no voluntary contraction of the
anal sphincter and absent sensation around the anus (the opening to the rectum).
An incomplete injury indicates that some messages are being transmitted. Depending
on the location and kind of injury, the interrupted messages may be either motor
or sensory or, a combination of both. When the injury is incomplete, the pattern
of interruption varies greatly from person to person.
The cord can be damaged by forces such as cutting, crushing, squeezing, bruising,
or by the effects of swelling or a decrease in blood supply. The level at which
the injury occurs will be a clue to the after-effects or permanent deficits (loss
of function). The higher up the cord, the greater the loss of function.
Based on spinal nerve distribution, a general picture of the effects of injury
at specific levels of the cord can be made.
Quadriplegia / Tetraplegia
The nerves that supply feeling and movement to the arms and hands, as well as
the nerves of the diaphragm come from the nerve roots in the cervical spinal
cord. If the cord is injured in this region, movement and sensation may be interrupted
to arms and hands as well as the rest of the body (including muscles in the abdomen,
chest and legs as well as, bladder bowel and sexual function). If the injury
is high enough that the diaphragm is affected, breathing problems will also occur.
Thus, quadriplegia is a condition that causes paralysis of both the upper and
lower limbs.
Paraplegia
An injury to the cord in the thoracic or lumbar spine may affect the legs and
trunk (abdomen and lower back) as well as bladder, bowel and sexual function,
but arms and hands are unaffected.