gluteal region, showing surface markings for arteries
and sciatic nerve.Sciatica is a pain in the leg caused
by compression and/or irritation of one of five nerve
roots that are branches of the sciatic nerve. The pain
is felt in the lower back, buttock, and/or various parts
of the leg and foot. In addition to pain, there may be
numbness, muscular weakness, and difficulty in moving
or controlling the leg. Typically, the symptoms are only
felt on one side of the body.
Left gluteal region, showing
surface markings for arteries and sciatic nerve.
Click Image To Enlarge
Although sciatica is a relatively common form of low back pain and leg pain,
the true meaning of the term often is misunderstood. Sciatica is a set
of symptoms rather than a diagnosis for what is irritating the root of
the nerve, causing the pain. This point is important, because treatment
for sciatica or sciatic symptoms often will be different, depending upon
the underlying cause of the symptoms.
Causes Of Sciatica
Sciatica is generally
caused by the compression of a lumbar spine nerve root
L4 or L5 or sacral nerve roots S1, S2 or S3, or far less
commonly, by compression of the sciatic nerve itself.
When sciatica is caused by compression of a lumbar nerve
root it is considered a lumbar radiculopathy (or radiculitis
when accompanied with an inflammatory response) from
a spinal disc herniation (a herniated intervertebral
disc in the spine), or from roughening, enlarging, and/or
misaligning of the vertebrae (spondylolisthesis), or
Sciatica may also be experienced in late pregnancy, primarily resulting from
the uterus pressing on the sciatic nerve, and, secondarily, from the muscular
tension and / or vertebral compression consequent to carrying the extra weight
of the fetus, and the postural changes inherent to pregnancy.
" Pseudo-sciatica", which causes symptoms similar to spinal nerve root
compression, is caused by the compression of peripheral sections of the nerve,
usually from soft tissue tension in the piriformis or related muscles. One possible
cause of this is the piriformis syndrome (PMID 17030664). In this condition,
the piriformis muscle, located beneath the gluteal muscles, contracts spasmodically
and strangles the sciatic nerve beneath the muscle. Another cause of sciatic
symptoms is sacroiliac joint dysfunction. Unhealthy postural habits, such as
excessive time sitting in chairs, and sleeping in the fetal position, along with
insufficient stretching and exercise of the relevant myofascial areas, can lead
to both the vertebral and soft tissue problems associated with sciatica.
Yet another source of sciatic symptoms is active trigger points of the lower
back and the gluteus muscles. In this case, the referred pain is not, in fact,
consequent to compression of the sciatic nerve, though the pain distribution
down the buttocks and leg is similar. Trigger points occur when muscles become
ischemic (low blood flow) due to injury or chronic muscular contraction. The
most commonly associated muscles with trigger points triggering sciatic symptoms
are: the quadratus lumborum, the gluteus medius, the gluteus minimus, and the
deep hip rotators.
One cause of sciatica is a spinal disc herniation, pressing on one of the sciatic
nerve roots. The spinal discs are composed of a spongiform cartilage with a
liquid center. The discs separate the vertebrae, thereby allowing room for
the nerve roots to properly exit through the spaces between the L4, L5, and
sacral vertebrae. The discs cushion the spine from compressive forces, but
are weak to pressure applied during rotational movements. That is why a person
who bends to one side, at a bad angle, to pick up a piece of paper may more
likely herniate a spinal disc than a person falling from a ladder and landing
on his or her back. Herniation of a disc occurs when the liquid center of the
disc bulges outwards, tearing the external ring of fibers, and compresses a
nerve root against the lamina or pedicle of a vertebra, thus causing sciatica.
Other compressive spinal causes include Spinal Canal Stenosis, a condition
wherein the spinal canal (the spaces through which the spinal cord runs) narrows
and compresses the spinal cord. This narrowing can be caused by bone spurs,
vertebral dislocation, or herniated disc which decreases available space for
the spinal cord, thus pinching nerves in the spinal cord that travel to the
sciatic nerve and irritating them with friction.
The sciatic nerve runs through the piriformis muscle in the buttocks region.
When the muscle shortens or spasms due to trauma, it can compress the sciatic
nerve. This cause of sciatic symptoms is piriformis syndrome, a major cause
of sciatica. The approach to treating Sciatica is to reduce the compressive
forces causing the pressure upon the sciatic nerve. This can be accomplished
through traction and realignment therapeutic procedures in the case where the
sciatica is spinal-related. Manual muscle stretching, massage, and mobilization
techniques should be used when the sciatica is piriformis muscle-related. General
therapeutic goals include helping the muscles loosen, thereby lessening pain,
and to minimize inflammation.
Don’t live life in pain!
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