Definition and causes of spinal cord injury

I. Cervical nerves. II. Thoracic nerves. III. Lumbar nerves.
IV: Sacral nerves.

The central nervous system comprises the brain and the sinal cord. 
From and to here run the peripheral nerves which are divided into 
posterior, or dorsal cells and anterior cells. The posterior nerves
transmit sensory impressions to the spinal cord and on to the brain
for processing. The brain's response is then transmitted via the spinal
cord to the anterior nerve ends and from there further onwards to
body parts and organs. The peripheral nerves located in the upper
spinal cord control the neck and arms. The thoracic nerves support
the thorax region and the lumbar and sacral nerves support the
lower back and the legs.

The spinal cord is usually well protected inside the spine, but if the spine is damaged, there is a high risk of injury to the spinal cord. The spinal cord is grey matter containing nerve cells together with various supporting cells enabling nerve impulses to be transmitted back and forth between the brain and the rest of the body. Some of the nerve cells are motor neurons projecting into long fibers named axons which reach out of the spine in bundles for further connectivity with body parts.

An injury to the spinal cord will lead to blockage of nerve impulses resulting in paralysis and/or tactile disturbances in the body parts governed by the damaged nerves. An injury located high in the spinal cord, for example in the neck, is more serious than an injury in lower in the spinal cord, for example in for example the lumbar region. The reason is that nerves impulses to and from the brain run through the upper spine, while only nerve impulses relating to the legs and the pelvis located organs run through the lower spine.

Damage to the spinal cord in younger persons (less than 30 years) usually stems from spine damage in connection with car accidents, falling or diving into swallow water hitting the bottom head first.

In the elderly damage to the spinal cord might be caused by a slipped disc, inflammation, spinal tumors or malformed blood vessels that can burst or exert pressure on the spinal cord. Besides, some infants are born with spinal hernia but this is a rare condition with an incidence of around 1 per 4.000 births in developed countries.

Symptoms of Spinal Cord Injury

There will typically be pain in the damaged area, often radiating to the arms or legs. Other symptoms depend on where in the spinal cord the damage is located and on whether spinal cord damage is sectional or affects the entire length of the spinal cord.

The nerves controlling urination and bowel movements are almost always affected resulting in incontinence for both urine and faeces or the opposite problems with emptying the bladder or constipation. There is a high risk bladder inflammation and subsequent damage to the kidneys. Men may experience problems with impotence.

Sudden injury often leads to what is called a spinal shock where the paralysis at the beginning is weak, and no reflexes. After the shock phase, which typically lasts 2-6 weeks the paralysis becomes spastic and the reflexes over active.

Precautions and diagnosis

Cross section of the spine.




I. Peripheral nerve.

Injury to the back is a serious condition where the patient should rest as comfortable as possible without being moved. Transport to the hospital should take place in a special ambulance or placed on a stretcher (spine board) supported by a stiff neck collar. An unconscious person who may have injured the back must be treated as if there is an injury to the spinal cord, until proven otherwise

Where there are signs or symptoms indicating damage to the spinal cord without injury or shock to the back urgent medical attention is advisable.

Fast medical examination is essential involving X ray and/or CT or MRI scanning together with thorough neurological examination to determine if there nerves malfunction can be determined.

Treatment of Spinal Cord Injury

Initially the main treatment is to avoid any further damage to the spinal cord. This is done by immobilizing the back and the neck. In case of spinal fracture the back must me immobilized until the fracture has healed which usually lasts 6 weeks. In some cases, such as slipped discs, fast surgery might be decisive for avoiding long-term damage. Similarly, surgery might be necessary if there is severe damage to the spine.

Damage caused to the spinal cord cannot be treated. However, rehabilitation with physiotherapists and occupational therapists assistance will help to make the most of the remaining functions. Insertion of electrodes for electrical stimulation of nerves can provide further function of the damaged parts, but not fully reverse the damage.

Different tools can alleviate some of the handicaps that have arisen and maybe help the patients fend for themselves. Often, the patient's home must be re-arranged to suit the new situation for example allowing movement in a wheelchair.

It is important to prevent complications and patients with damage to the spinal cord are often monitored for life by special clinics or staff. Since there also often serious psychological reactions in connection with invalidation and lifelong dependency on others there may be a need for psychological assistance or interaction with others in the same situation.

Outlook and complications

If there has been damage to the spinal cord the outlook for improvement is dim with only limited progress and there might be the following complications:

• Paralysis results in wasting of the paralyzed muscles.
• The spasticity results stiffness of joints and distortion of joint positions.
• Lack of tactile sense increases the risk of tissue pressure damage and there is often pain in the areas where there is no longer normal tactile sense.
• The lack of physical activity can lead to changes in metabolism and bone calcium depletion.
• Moreover, there is a risk of leg thrombosis (blood clot in the legs).

The nerve ends controlling the breathing are located at the very top of the spinal cord so an injury here would mean that breathing stops. Damage in the neck portion of the spinal cord causes paralysis of all 4 limbs (tetraplegi), While damage further down only leads to paralysis of the legs (paraplegia). In addition sensory ability in the same area might be affected.

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