Spinal Cord Injury : Quadriplegic and Paraplegic Injuries

A Spinal Cord Injury (SCI) is typically defined as damage or trauma to the spinal cord that in turn results in a loss or impaired function resulting in reduced mobility or feeling.

Paraplegic and Quadriplegic are terms used to describe the medical condition, for a person who has been paralyzed due to a spinal cord injury. This classification depends on the level and severity of a person’s paralysis, and how it affects their limbs.

Typical common causes of damage to the spinal cord, are trauma (car/motorcycle accident, gunshot, falls, sports injuries, etc), or disease (Transverse Myelitis, Polio, Spina Bifida, Friedreich's Ataxia, etc.). The resulting damage to the spinal cord is known as a lesion, and the paralysis is known as Quadriplegia if the injury is in the Cervical (neck) region or as Paraplegia if the injury is in the Thoracic, Lumbar or Sacral region.

One thing to remember is that a person who is paralyzed is not simply lacking the ability to move from the waist down. Every injury is different. Paraplegics can vary greatly in their ability to perform everyday activities. Obviously, Quadriplegics have even more difficulty and often need assistance. It is possible for someone to suffer a Broken Neck, or a Broken Back without becoming paralyzed. This occurs when there is a fracture or dislocation of the vertebrae, but the spinal cord has not been damaged.

Complete and Incomplete Spinal Cord Injury

There are typically two types of lesions associated with a spinal cord injury, these are known as a complete spinal cord injury and an incomplete spinal cord injury. A complete type of injury means the person is completely paralyzed below their lesion. Whereas an incomplete injury, means only part of the spinal cord is damaged. A person with an incomplete injury may have sensation below their lesion but no movement, or visa versa. There are many types in incomplete spinal cord injuries, and no two are the same.

Spinal Cord Anatomy

The Spinal Cord is connected to the brain and is about the diameter of a human finger. From the brain the spinal cord descends down the middle of the back and is surrounded and protected by the bony vertebral column. The spinal cord is surrounded by a clear fluid called Cerebral Spinal Fluid (CSF), that acts as a cushion to protect the delicate nerve tissues against damage from banging against the inside of the vertebrae.

The anatomy of the spinal cord itself consists of millions of nerve fibers which transmit electrical information to and from the limbs, trunk and organs of the body, back to and from the brain. The brain and spinal cord are referred to as the Central Nervous System, whilst the nerves connecting the spinal cord to the body are referred to as the Peripheral Nervous System.

The nerves within the spinal cord are grouped together in different bundles called Ascending and Descending tracts. Ascending tracts within the spinal cord carry information from the body, upwards to the brain, such as touch, skin temperature, pain and joint position. Descending tracts within the spinal cord carry information from the brain downwards to initiate movement and control body functions. Nerves called the spinal nerves or nerve roots come off the spinal cord and pass out through a hole in each of the vertebrae called the Foramen to carry the information from the spinal cord to the rest of the body, and from the body back up to the brain.
There are four main groups of spinal nerves that exit different levels of the spinal cord. These are in descending order down the vertebral column:
Cervical Nerves "C": (nerves in the neck) supply movement and feeling to the arms, neck and upper trunk.
Thoracic Nerves "T": (nerves in the upper back) supply the trunk and abdomen.
Lumbar Nerves "L" and Sacral Nerves "S": (nerves in the lower back) supply the legs, the bladder, bowel and sexual organs.
The spinal nerves carry information to and from different levels (segments) in the spinal cord. Both the nerves and the segments in the spinal cord are numbered in a similar way to the vertebrae. The point at which the spinal cord ends is called the conus medullaris, and is the terminal end of the spinal cord. It occurs near lumbar nerves L1 and L2. After the spinal cord terminates, the spinal nerves continue as a bundle of nerves called the cauda equina. The upper end of the conus medullaris is usually not well defined.

There are 31 pairs of spinal nerves that branch off from the spinal cord. In the cervical region of the spinal cord, the spinal nerves exit above the vertebrae. A change occurs with the C7 vertebra however, where the C8 spinal nerve exits the vertebra below the C7 vertebra. Therefore, there is an 8th cervical spinal nerve even though there is no 8th cervical vertebra. From the 1st thoracic vertebra downwards, all spinal nerves exit below their equivalent numbered vertebrae.

The spinal nerves which leave the spinal cord are numbered according to the vertebra at which they exit the spinal column. So, the spinal nerve T4, exits the spinal column through the foramen in the 4th thoracic vertebra. The spinal nerve L5 leaves the spinal cord from the conus medullaris, and travels along the cauda equina until it exits the 5th lumbar vertebra. 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 spinal nerve level.

Myotomes & Dermatomes

Spinal nerves have motor fibers and sensory fibers. The motor fibers innervate certain muscles, while the sensory fibers innervate certain areas of skin. A skin area innervated by the sensory fibers of a single nerve root is known as a dermatome. A group of muscles primarily innervated by the motor fibers of a single nerve root is known as a myotome. Although slight variations do exist, dermatome and myotome patterns of distribution are relatively consistent from person to person.

Each muscle in the body is supplied by a particular level or segment of the spinal cord and by its corresponding spinal nerve. The muscle, and its nerve make up a myotome. This is approximately the same for every person and is as follows:

C3, 4 and 5 supply the diaphragm.
C5 also supplies the shoulder muscles and the muscle that we use to bend our elbow.
C6 is for bending the wrist back.
C7 is for straightening the elbow.
C8 bends the fingers.
T1 spreads the fingers.
T1 –T12 supplies the chest wall & abdominal muscles.
L2 bends the hip.
L3 straightens the knee.
L4 pulls the foot up.
L5 wiggles the toes.
S1 pulls the foot down.
S3,4 and 5 supply the Bladder, the bowel and sex organs and the anal and other pelvic muscles.

A dermatome is an area of the skin supplied by nerve fibers originating from a single dorsal nerve root. The dermatomes are named according to the spinal nerve which supplies them. The dermatomes form into bands around the trunk but in the limbs their organization is more complex as a result of the dermatomes being "pulled out" as the limb buds form and develop into the limbs during embryological development.

In diagrams or maps, the boundaries of dermatomes are usually sharply defined. However, in life there is considerable overlap of innervation between adjacent dermatomes. Thus, if there is a loss of afferent nerve function by one spinal nerve sensation from the region.

Associated Issues common with Spinal Cord Injury

There are several health issues that are associated with spinal cord injury that many people are unaware of. These issues greatly compound the fact of having a spinal cord injury and being paralyzed. If one were simply paralyzed and unable to move or feel is one thing. However, the constant battle with these associated issues makes life extremely difficult. The following is just a list of frequent issues that a person with a spinal cord injury will have to manage:
-Managing bowel and bladder functions. This is probably one of the most troublesome areas for spinal cord patients ranging from social implications to several health complications.
-Pain management. Typical neurological pain issues are phantom pain, burning pain, root pain, and neuropathy. However, overuse injuries on joints (shoulders primarily) are also prevalent.
-Temperature regulation. Spinal cord patients typically suffer from the inability to regulate their body temperature when faced with cold or hot climates. The inability to sweat below their injury level makes life difficult in hot climates. Poor circulation can make maintaining warmth in a cold climate difficult.
-Compromised breathing ability. If the injury level is normally above T12, there will likely a decreased ability to breath. It can range from a complete inability to breath on their own which requiring a ventilator; to the inability to fully cough.
-Lack of circulation. The lack of circulation results in issues such as edema, poor injury healing, poor heat regulation, etc.
-Pressure sores, skin ulcers, or “bed sores.” This can be a deadly issue for spinal cord patients due to infection.
-Muscle spasms. Spasticity is an exaggeration of the normal reflexes that occur when the body is stimulated in certain ways.

The above list is just a few of the more common issues faced by a spinal cord injury patient. These issues do not go away with time and are a constant struggle. The thing to remember is that every person’s injuries and issues are different.

Spinal Cord Injury Rehabilitation

Someone with a spinal cord injury will have a long road of rehabilitation and it is important that they keep their sense of humor on their bad days to help them maintain a positive attitude. Both Paraplegics and Quadriplegics should have some kind of rehabilitation and physiotherapy before they are discharged from hospital, to help maximize their potential, or help them get used to life in a wheelchair, and to help teach techniques which make everyday life easier.

The above information was partially gathered from www.apparelyzed.com