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The Spinal Column - Essential structure and the consequences of injury explained.

Updated on September 2, 2016
The Spine
The Spine

Many of us do not understand the function & construction of the spine and the consequences of injury to this vital part of our body. I have tried to keep it as jargon free as possible, but it is essential to know the terms and what the parts are called to understand how the spine works and identify their position.

The Spinal Column is also known as the Vertebral Column. In the skeleton it starts at the base of the skull and extends to the pelvis (hip area). The spinal column consists of 33 bones known as vertebrae which are stacked one on top of each other. For identification the spine is sub-divided into five regions which are known by the medical profession by their abbreviated letter and number.

Abbreviation ……Region……No.of vertebrae…….Body Area

C1 – C7………….Cervical…..7……………………..Neck

T1 – T12………...Thoracic…..12……………………Chest

L1 – L5…………..Lumber…….5 or 6……………….Low Back

S1 – S5………….Sacrum…….5 (fused)……………Pelvis

None……………..Coccyx…….3…………...………..Tailbone

We can look at each region in turn. The cervical spine region is sub divided into two parts; upper (C1 and C2) and lower (C3 - C7). C1 is the “Atlas” and C2 the “Axis”. Also, there is a flat bone, called the Occipital Bone that forms the back of the skull. Vertebrae C3 through C7 are not actually named. Staying with the first two bones, for the moment, they are vital to the construction and operation of the head and spine. Atlas (C1) is the first cervical vertebra, which is ring shaped, acts as a supports for the skull and is different in appearance to the other vertebrae. Axis (C2) is the second cervical vertebra which is shaped like a tooth and sticks upward to engage with the ring of the Atlas. This part of the Axis is called the "dens" (Latin for "tooth"). The dens or tooth extends from the C2 vertebral body and joins with the inside of the C1 ring. The Atlas and Axis is what allows the head to rotate from side to side.

The spinal column has five primary functions:

1. It offers physical protection to the spinal cord and nerve roots, while at the same time protecting all the chest and abdominal organs.

2. It forms the base structure for attachment of the Ligaments, Tendons and Muscles.

3. It gives structural support to the Head, shoulders, chest and forms the connection of the upper and lower body. This allows for balance and weight distribution.

4. The 33 bones of the spine gives us flexibility and mobility, allowing for forward bending (flexion), extension (backward bending), side bending (left and right), rotation (left and right) and a simultaneous combination of all the above.

5. The actual bones product red blood cells and allows for mineral storage.

Much of the body's weight is carried by the vertebrae which have soft cushion discs between them. They vary in size with the cervical vertebrae being the smallest and the lumbar the largest.

The spine distributes the upper body weight to the load bearing pelvis. Using the natural curves in the spine (kyphotic and lordotic) helps to distribute this body weight and stress during twisting and turning.

The actual bony spinal column protects the spinal cord, which extends for around 18 inches from the brain stem, down the middle of the back, to about the waist area. These nerves, contained within the spinal cord, are the upper motor neurons and their function is to carry the impulses to and from the brain to the spinal nerves along the spinal tract. These spinal nerves branch out from the spinal cord to all parts of the body are called lower motor neurons. Each vertebra has spinal nerves exiting and entering for communication with specific areas of the body. The sensory spinal nerves carry information about sensation from the skin and other body parts and organs to the brain. The motor spinal nerves send information from the brain to the relevant body parts to actuate muscle movement.

As we have said, the vital spinal cord is the major bundle of nerves that carries the impulses to and from the brain to the rest of the body. In appearance the outer covering looks a little like a flexible pipe which encases the nerves. The brain and spinal cord combines to form what is known as the Central Nervous System (CNS). Away from the CNS the Motor and sensory nerves form the Peripheral Nervous System (PNS) and yet another separate system of nerves, known as the Sympathetic and Parasympathetic Nervous System control the involuntary functions such as blood pressure and temperature regulation.

Spinal Injury

In the case of spinal injuries where the cord itself has been damaged, you will find the higher up the spinal column the injury occurs, the more dysfunction a person will suffer. The following is a general guide only and can vary according to the extent of the injury.

Spinal cord injuries in the cervical area usually cause a loss of function in the arms and legs, often resulting in quadriplegia.

The first thoracic vertebra, T-1, is the vertebra to which the top rib attaches.
Injuries in the thoracic region usually affect the chest and the legs and can result in paraplegia.

The vertebra in the lower back between the thoracic vertebra, where the ribs attach, and the pelvis (hip bone), are known as the Lumbar Vertebra.

The sacral vertebras run from the Pelvis to the end of the spinal column, around the waist area. Injuries to the five Lumbar vertebra (L-1 thru L-5) and similarly to the five Sacral Vertebra (S-1 thru S-5) generally result in the possible loss of functioning in the hips and legs.

The effects of a spinal cord injury (SCI) depend on the type of injury and the degree of damage (i.e. fall, crush, gunshot, motor or horse riding accident, etc). Further, we should consider that the SCI can appear as two types - complete and incomplete. In the case of a complete injury there will be no function below the level of the injury, no sensation or voluntary movement on either side of the body. An incomplete injury, however, can leave some function below the primary level of the injury. In cases such as this a person with an incomplete injury may have the limited movement of one limb which can be more or less than the another and also may have feeling in parts of the body that are actually immovable. The treatment of SCI is becoming more successful and in consequence incomplete injuries are becoming more common.

Whether the injury is complete or incomplete is very helpful indicator in predicting what parts of the body might be affected by paralysis and loss of function. To this end we can now be a little more precise as to the extent of the disability

In the case of Cervical (neck) injuries, it usually result in quadriplegia (loss of movement and feeling in both hands, feet and areas below the injury level)

For injuries above the C-4 level the patient may require a ventilator to breathe.

C-5 injuries often retains shoulder and biceps control, but no control in the wrist or hand.

C-6 injuries often retain wrist control, but no hand function.

Patients with C-7 and T-1 injuries can straighten their arms but will still have mobility problems with the hand and fingers.

Injuries at the thoracic level and below will result in paraplegia, but with the hands not affected.

At T-1 to T-8 the patient most often retains control of the hands, but could have poor trunk control due to the lack of abdominal muscle control.

Lower T-injuries (T-9 to T-12) still allows good trunk and abdominal muscle control and sitting balance should remain good.

Lumbar and Sacral injuries can result in decreasing control of the hip flexors and legs.
As well as a loss of sensation or motor functioning to the limbs etc., patients with SCI also can experience some other serious changes.

There may be dysfunction of the bowel and bladder, sexual function is frequently compromised with SCI and males may have their fertility affected, while conversely women's fertility is generally not affected.

Very high injuries (C-1, C-2) can result in a loss of many involuntary functions such as breathing, which will then require mechanical aids such as ventilators or diaphragmatic pacemakers.

In addition low blood pressure may occur, with an inability for the body to regulate blood pressure effectively. Also there may be reduced control of body temperature which will cause the body to be unable to sweat below the level of the injury together with chronic pain which will require some form of permanent pain relief.

Some spinal injuries, previously considered to be irreversible, may be repaired by the use of stem cell technology, which has made great strides recently.

Never self-diagnose potential spinal problems or ignore what you may consider to be minor spinal or neck injury.

Your doctor is not necessarily the best qualified to diagnose spinal injury problems, but are usually quite agreeable to send you to a specialist who may order x-rays or scans to determine the extent of the problem.

Equally don’t panic if you just have a stiff or aching back, particularly after working in the garden or similar. As our bodies get older we can all suffer from deterioration of the soft tissue cushions (discs) between the vertebra that may allow the cushions to bulge putting pressure on the nerves and perhaps even allowing the bones to rub against each other.

I have restricted myself to talk only about trauma injury, but back pain can also be a symptom of disease and for that reason, particularly if there is no apparent reason such as injury or simply overdoing it, then it is essential that you seek medical advice as quickly as possible.

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© 2012 Peter Geekie

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    • teaches12345 profile image

      Dianna Mendez 4 years ago

      Wow, this is really detailed information and very interesting. I guess stem cell research is a good thing if it can help with spinal injuries. You certainly have done some intensive research and this will prove very useful to readers.

    • Peter Geekie profile image
      Author

      Peter Geekie 4 years ago from Sittingbourne

      Dear teaches12345,

      The spine is something we tend to take for granted without appreciating the catastrophic effect if it becomes damaged.

      Thank you for your comment.

      kind regards Peter

    • TheListLady profile image

      TheListLady 4 years ago from New York City

      It is almost too hard for me to read this. I have not only injured my back and have spinal stenosis but it turns out I had lesions on the spine as well and had to undergo radiation.

      You are right - the suffering can be unbearable. I even lost the ability to walk for awhile, had to be hospitalized and even went into rehab. I am back home now and recovering - but what a shock.

      And I hope many of us sitting and writing for hours each day as I was take into consideration the harm they are doing to their back. Please get an ergonomic chair and please get up and walk around.

      Thanks for an incredibly well done - article!

    • Peter Geekie profile image
      Author

      Peter Geekie 4 years ago from Sittingbourne

      Dear TheListLady,

      Thank you for your comments and I'm glad you found it of some use.My interest in the spine started nearly 40 years ago when I had a serious motorcycle crash. Over the years it has deteriorated and nowadays my walking is severely limited and I rely on an electric scooter and a specially made off-road wheelchair for my clay shooting. I'm lucky, my pain is under control normally and with a bit of effort I can still enjoy my hobbies. I wish you well and perhaps new treatments using stem cells will be able to offer relief to many sufferers.

      Kind regards Peter

    • BkCreative profile image

      BkCreative 4 years ago from Brooklyn, New York City

      It's taking me forever to recover from spinal stenosis but as I lay here and then dodder around I realize how many, many things we do wrong to our back over the course of decades. Finally it caught up with me. Whew! I'm wondering if inversion therapy will help.

      Surprisingly, to alleviate some of the pain and stiffness I started taking a clove of black garlic each day. Black garlic is fermented garlic and still pretty new here in the USA - but it seems to be helping.

      Thanks for this hub - it is a reminder that our backs are everything!

    • Peter Geekie profile image
      Author

      Peter Geekie 4 years ago from Sittingbourne

      Dear BkCreative,

      I am so sorry to hear of your spinal problem and sincerely wish you well and a speedy recovery.

      I'm not sure if you have tried Reiki - I have recently and the response of my body has been remarkable. As a scientist I have a built in skepticism for power of the mind healing and maybe it won't work for everyone but I think it worth gambling 50dollars (that's about the price in London) or so

      on an initial treatment. You have very little to lose.

      Kind regards Peter

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