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Spine
The spine is made up of three sections: 7 cervical vertebrae in the neck, 12 thoracic
vertebrae to which the ribs attach, and 5 lumbar vertebrae in the lower back.
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Vertebra
Vertebra is the individual bone that makes up the spine. It is made up of several
parts. The body is toward the front – this is the primary area of weight bearing
and is where the disc rests. The lamina covers the spinal canal, which is the large
hole in the center of the vertebra where the spinal cord comes through. The spinous
process is the bump you feel when running your hands down your back. There is a
transverse process on each side, this is where the back muscles attach.
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Stenosis
Spinal Stenosis occurs when the spinal canal narrows and presses on the spinal cord
and/or the exiting nerve roots. It can occur anywhere in the spine. Central canal
stenosis is when the channel that the spinal cord passes through narrows. Foraminal
stenosis is a narrowing of the channel on either side of the vertebra where the
spinal nerve roots exit on their way to the body (ie. down the arms or legs). Cervical
spinal stenosis can result in neck pain that may radiate into the shoulders, arms,
wrists, and hands. Lumbar spinal stenosis results in low back pain that can radiate
down the nerves into the hips, legs, thighs, feet or buttocks.
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Spondylolisthesis
This describes the anterior (forward) displacement of a vertebra in relation to
the vertebrae below. Spondylolithesis often contributes to spinal stenosis. Most commonly,
its severity is graded using a lateral x-ray. The measurements of the distance from
the posterior (back) edge of the superior (above) vertebral body to the posterior
edge of the adjacent inferior (below) vertebral body is reported as a percentage
of the total superior vertebral body length: Grade I is 0-25%, Grade II is 25-50%,
Grade III is 50-75%, Grade IV is 75-100% . Fredrickson, et al. demonstrated that
the spondylolytic defect is usually acquired between the ages of 6 and 16 years,
and that the slip often occurs shortly thereafter. Once the slip has occurred it
rarely continues to progress. It may or may not be symptomatic, but it is significant
because abnormal biomechanical stresses cause a greater likelihood of disc degeneration
and associated osteoarthritic changes at this level.
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Degenerative Disc Disease
Degenerative Disc Disease (DDD) is not really a "disease," but rather a
term used to describe a condition that develops gradually and worsens over time.
DDD indicates that the discs in the spine are the primary cause of the symptoms,
and that the degenerative changes are advanced. To some degree intervertebral discs
lose their flexibility, elasticity, and shock absorbing characteristics as we age.
Abnormal or excessive mechanical stresses/injuries of the past coupled with hereditary,
developmental, and metabolic influences can rapidly accelerate this process.
As the involved disc dries out and loses height, it causes the vertebra to become
closer together which narrows the holes through which the nerve roots pass. A dry,
hard disc can absorb less shock and is more easily torn. This results in a greater
likelihood of herniation or bulge which further compresses or pinches the nerves.
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Degenerative Joint Disease / Osteoarthritis (OA)
Osteoarthritis (OA) is also known as degenerative arthritis or Degenerative
Joint Disease (DJD). In the spine, it usually means that multiple osteoarthritic
changes are found in several areas. Any joint in the body can be exposed to abnormal
or excessive mechanical stress or injury, however, the weight bearing joints of
the spine, hip, and knee are the most common.
Factors that can contribute to the development of OA are: old injuries, poor health
habits, a weakened immune system, and/or hereditary factors. Osteoarthritis is not
a disease in the sense that a patient can "catch it", but is the body's natural
response to abnormal or excessive mechanical stress over time coupled with hereditary,
developmental, and metabolic influences. It is not necessarily a disease of the
old because many younger people can have abnormal or excessive mechanical stress
too, and not all older people do.
Osteoarthritis is the most common form of arthritis and the leading cause of chronic
disability in the United States. As the stress continues and accelerates the joints
may lose normal contour and abnormal amounts of fluid may build up inside the joint
along with pieces of floating debris. Early on, a patient may only experience joint
aches after physical work or exercise, which fades and then returns as the affected
joint is used or overused. As the cartilage between the bones gradually thins, the
patient increasingly experiences pain upon weight bearing, including walking, standing,
and sitting as well as many other movements in between.
As a result of the patients attempt to avoid certain movements because of the pain,
regional muscles may atrophy and ligaments may become more lax while other muscles
may spasm in an attempt to limit the abnormal motion and reduce the pain, all resulting
in further stress to the involved joints thereby accelerating and worsening the
process. Now, the joint pain and stiffness occurs after periods of inactivity such
as while sitting for long car rides or watching a long movie. Later, the pain often
becomes substantial even at complete rest or with very little movement. This is
the degenerative cycle in action - where everything makes everything else worse
in an accelerating downward spiral of pain and disability.
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Osteophyte
An Osteophyte is often called a bone spur. This describes osteoarthritic changes
that are a projection of bone that grows along the edges of joints at the attachment
points for ligaments and tendons. The evidence of bone spurs can be found on an
x-ray. These are frequently found on the edges of vertebral bodies where the spinal
disc attaches to the bone (end plate of the vertebra). The body produces osteophytes
to try to stop the motion of the arthritic joint and deal with the degenerative
process. It never completely works. Hips, knees, and the joints of the fingers are
other common locations in which to find these bone spurs.
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Spondylosis
Spondylosis is referring to the osteoarthritic changes of multiple spinal vertebra
at the level of the discs. If severe, it may cause pressure on nerve roots which
then causes pain, parasthesia, or muscle weakness in the limbs. Use of this term
indicates that the facet joints at the back of the vertebrae are not necessarily
involved.
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Hypertrophy
Hypertrophy means a thickening or overgrowth of the ligaments which help hold the
spinal bones together. Tissue responds to biomechanical stress through hypertrophy
(an increase in the size of cells) or hyperplasia (an increase in the number of
cells). As an example, excessive or prolonged stress to the skin of the hands or
feet results in a hypertrophy of the skin known as callous formation. Spinal ligaments,
specially the ligamentum flavum along the posterior aspect of the spinal canal,
respond to stress by thickening in the same way. The problem with this is that there
is little ''extra'' room along the spinal canal. If one tissue is thicker than it
should be another is being compressed or pinched.
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Sclerosis
Sclerosis to describes areas of increased density or whiteness found on X-ray or
MRI examination. This is indicative of a calcium buildup in areas of excessive stress
to form osteoarthritic bone. This depicts an early stage of osteoarthritis and with
continued stress will eventually become osteophytes (bone spurs).
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Pinched Nerve
A pinched nerve occurs when too much pressure is applied for too long to a nerve
by surrounding tissues. Tissues that can cause the pressure can be bones, cartilage,
muscles, tendons, ligaments, spinal discs or (rarely) tumor. The most common reasons
for the direct physical pressure are as a result of the changes occurring with degenerative
joint disease or degenerative disc disease. Nerve pain resulting from direct physical
pressure is called an entrapment neuropathy because the nerve is trapped or pinched
by some structure. This term helps to distinguish them from neuropathies resulting
from infection or disease.
A good example of this concept is when you “bump your funny bone” (which is actually
the ulnar nerve). This physical pressure disrupts the nerve's function causing pain,
tingling, numbness or weakness. Too much pressure applied for too long to a nerve
along the spine results in much the same sensations.
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Neuritis / Neuralgia
Neuritis describes nerve inflammation while neuralgia describes nerve pain. The
most common cause of neuritis or neuralgia for those suffering from arm pain or
leg pain is direct physical pressure as a result of the changes occurring with degenerative
disc disease (DDD) and/or degenerative joint disease (DJD).
The pain may radiate anywhere along the course of the nerve and is most often described
as a burning, stabbing, or shooting pain from the neck into the shoulder, arm, elbow,
wrist, or hand. If the nerve originates in the lower back the pain radiates into
the buttock, hip, thigh, leg, or foot.
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Paresthesia
Paresthesia is when there is involvement of the sensory nerves described as numbness
or tingling, but not really pain, and with no motor or muscle weakness. In the medical
community neuritis / neuralgia / paresthesia are often used interchangeably without
clear distinction and simply mean that the nerve is irritated and causing symptoms.
The symptoms often include actual pain, but may be limited to numbness, tingling,
burning, stinging, prickling, pins and needles, skin crawling, or itching,
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Radiculitis / Radiculopathy
These are not specific conditions, but describe a nerve that is being pinched at
or very near the spinal cord at the beginning (root) of the nerve. The most common
cause of radiculitis/radiculopathy is a herniated or protruding spinal disc that
results in pain at that area of the neck or back. The most severe symptoms may be
noticed along the course of the adjacent nerve root resulting in arm pain or leg
pain through. This process is called referred pain or radicular pain.
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Sciatica / Sciatic Neuritis / Sciatic Nerve Pain / Leg Pain
Sciatica (or Sciatic Neuritis) is caused by compression and/or irritation of one
of five nerve roots that exit the lumbar spine that join together to form the sciatic
nerve. This nerve runs through the buttock muscles, past the hip joint, into the
thigh, past the knee, down into the calf, ankle, and foot to the toes. Sciatica
is usually caused by the compression of lumbar nerve roots L4 or L5 or S1, but sometimes
sacral nerve roots S2 or S3. The symptoms are felt in the lower back, buttock, hip
and/or various parts of the leg and foot. In addition to pain, which is sometimes
severe, there may be numbness, muscular weakness, tingling, and difficulty in supporting
weight on the affected leg.
Sciatica is a set of symptoms, rather than a diagnosis, for what is irritating the
root of the nerve causing the pain. The most common causes of sciatica are degenerative
disc disease or degenerative joint disease. It may also be caused by pregnancy or
nerve entrapment. .
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Piriformis Syndrome
In approximately 15% of the population, the sciatic nerve runs through
the piriformis muscle rather than beneath it. When the muscle shortens or spasms
due to trauma or overuse, it can compress or pinch the sciatic nerve beneath the
muscle. This can be referred to as entrapment neuropathy. Piriformis Syndrome is
often the major cause of sciatica when the nerve root is normal.
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Inflammation
Inflammation is characterized by redness and heat due to increased blood flow to
the inflamed site; swelling caused by accumulation of fluid; and pain due to release
of chemicals involved in the repair process that irritate nerve endings. If your
body did not produce inflammation when injured, the damaged cells would never heal
and progressive destruction of the tissue would continue.
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Herniated Disc
Herniated discs occur when the spinal disc becomes less elastic. When the disc ruptures,
a portion of the spinal disc pushes outside its normal boundary--this is called
a herniated disc. When a herniated disc bulges out from between the vertebrae, the
spinal nerves and spinal cord can become pinched. There is normally a little extra
space around the spinal cord and spinal nerves, but if enough of the herniated disc
is pushed out of place, then these structures may be compressed. Symptoms are due
to the irritation of the nerve from the herniated disc. Because of the nerve irritation,
signals from the brain may be interrupted causing muscle weakness. Nerve irritation
can also be tested by examining reflexes. Bowel or Bladder Problems are very important
symptoms because it may be a sign of cauda equina syndrome, which is a possible
condition that can result from a herniated disc. (**This is a medical emergency,
and your should see your doctor immediately if you have problems urinating, having
bowel movements, or if you have numbness around your genitals)
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