back is a complicated arrangement of bones,

ligaments, muscles, tendons and nerves. — In some ways it is amazingly strong, yet

it can

easily be damaged.  Many of us don't take the precautions

that are

necessary to protect our backs from injury. — Which is why more than 80% of both on

and off

the job injuries involve the back or neck.  But back problems are not inevitable.

— You can prevent back injuries, if you

understand how the back "works.  When we say that someone has a lot of

"backbone" we mean that they are "upstanding" and

solid. — Yet our backs are also amazingly flexible.

— The "foundation" of your back, the spine, is

rigid enough to support more than half of your

body weight. — But the spine also has enough flexibility

for

you to bend down and touch your toes. 2

 To accomplish these "dual functions" the spine

is made up of 33 individual bones known as

"vertebrae," twenty four of which are moveable.

They are: — The seven "cervical" (neck) vertebrae...

which

support your skull and allow you to move your

head. — The twelve thoracic (middle back) vertebrae...

which hold your rib cage in place. — The five vertebrae in the "lumbar" region

of

your back... which enable you to bend at the waist.

 These vertebrae are "hinged" with "facet

joints" that guide their movement and provide

stability.  The vertebrae are cushioned from one another

by

"intervertebral discs." — These "shock absorbers" consist of a soft,

gelatinous nucleus surrounded by a tough, elastic

outer casing.

Because the lumbar and cervical regions of the

spine are so flexible, these areas are

particularly vulnerable to injury. — In fact most people will end up hurting

the

lumbar region of their backs at some point in

their lives. — The resulting pain can be anything from

a

persistent dull ache... to a sudden, sharp stabbing

or stinging sensation.  Strained muscles and sprained ligaments

are the

most common causes of back pain. — With proper treatment these injuries usually

heal within a few weeks. — Back pain like this that lasts less than

three

months is considered to be an "acute" condition.  When back pain persists or frequently

reoccurs,

it is considered to be "chronic." — Chronic back pain may indicate that something

is wrong with the spine itself.  "Ruptured" or "herniated" discs are the

most

common type of spinal injury. — Although sometimes referred to as a "slipped"

disk, intervertebral discs don't really pop out

from between the vertebrae. — What actually happens is that the outer,

elastic part of the disk ruptures, and the

gelatinous nucleus protrudes into the spinal

canal... putting pressure on the spinal cord. — This causes severe back pain... and since

the

spinal cord is directly involved, there is often

numbness or pain in other parts of the body as

well.  Most disc ruptures occur to the lower

two discs

in the lumbar region. — This is because they are subjected to

more

"heavy lifting" than any other discs in the

spine. 4

 However, herniated discs can also occur in the

cervical region. Often, these injures are due to

"whiplash." — Whiplash is caused by any sudden jolt,

such as

a car accident, that violently throws the head

backwards.  Properly treated, herniated discs usually

heal

by themselves, without the need for surgery. — But it can take several years for a disc

to

fully heal.