Causes of Sciatica:
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Sciatica (or sciatic neuritis) is a set of symptoms including pain that may be caused by general compression and/or irritation of one of five spinal nerve roots (the nerves roots L4, L5 and S1, S2 and S3 form the sciatic nerve) that give rise to each sciatic nerve, or by compression or irritation of the left or right or both sciatic nerves. The pain is felt in :
In addition to pain, which is sometimes severe, there may be numbness, muscular weakness, pins and needles or tingling and difficulty in moving or controlling the leg. Typically, the symptoms are only felt on one side of the body. Pain can be severe in prolonged exposure to cold weather.
Although sciatica is a relatively common form of low back pain and leg pain, the true meaning of the term is often 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 will often be different, depending upon the underlying cause of the symptoms.
The pain often starts slowly. Sciatica pain may get worse:
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After standing or sitting
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At night
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When sneezing, coughing, or laughing
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When bending backwards or walking more than a few yards, especially if caused by spinal stenosis |
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Causes
Sciatica is generally caused by the compression of lumbar nerves L4 or L5 or sacral nerves S1, S2 or S3, or by compression of the sciatic nerve itself. When sciatica is caused by compression of a dorsal nerve root (radix) it is considered a lumbar radiculopathy (or radiculitis when accompanied with an inflammatory response). The intervertebral discs consist of an annulus fibrosus which forms a ring surrounding the inner nucleus pulposus. When there is a tear in the annulus fibrosis, the nucleus pulposus (pulp) may protrude through and push against spinal nerves within the spinal cord or those exiting, causing numbness or excruciating pain. Sciatica due to compression of a nerve root is one of the most common forms of radiculopathy.
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 Habits the risk of self-inflicted sciatica has increased in recent years with, for instance, sitting on a wallet or standing for prolonged periods of time every day which can cause self-inflicted sciatica. Symptoms of numbness and/or pain behind the knee cap are associated with this form of sciatica. Work-related sciatica may be caused by the use of tool belts which hang around the hips and cause significant misalignment of the sacral vertebrae over long time periods.
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Pseudosciatica or non-discogenic sciatica, which causes symptoms similar to spinal nerve root compression, is most often referred pain from damage to facet joints in the lower back and is felt as pain in the lower back and posterior upper legs. Pseudosciatic pain can also be caused by compression of peripheral sections of the nerve, usually from soft tissue tension in the piriformis or related muscles.
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Spinal disc herniation One of the possible causes of sciatica is a spinal disc herniation pressing on one of the sciatic nerve roots. The spinal discs are composed of a tough spongiform ring of cartilage (annulus fibrosus) with a more malleable center (nucleus pulposis). 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 something up, may more likely herniate a spinal disc than a person jumping from a ladder and landing on his or her feet.
 Herniation of a disc occurs when the liquid center of the disc bulges outwards, tearing the external ring of fibers, extrudes into the spinal canal, and compresses a nerve root against the lamina or pedicle of a vertebra, thus causing sciatica. This extruded liquid from the nucleus pulposus may cause inflammation and swelling of surrounding tissue which may cause further compression of the nerve root in the confined space in the spinal canal.
Sciatica caused by pressure from a disc herniation and swelling of surrounding tissue can spontaneously subside if the tear in the disc heals and pulposis extrusion and inflammation cease.
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Sciatica can be caused by tumors impinging on the spinal cord or the nerve roots. Severe back pain extending to the hips and feet, loss of bladder or bowel control, or muscle weakness, may result from spinal tumors. Trauma to the spine, such as from a car accident, may also lead to sciatica.
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Spinal stenosis Other compressive spinal causes include lumbar spinal stenosis, a condition in which the spinal canal (the spaces through which the spinal cord runs) narrows and compresses the spinal cord, cauda equina, and/or sciatic nerve roots. This narrowing can be caused by bone spurs, spondylolisthesis (the anterior displacement of a vertebra or the vertebral column in relation to the vertebrae below), inflammation, or herniated disc which decreases available space for the spinal cord, thus pinching and irritating nerves from the spinal cord that travel to the sciatic nerves.
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Pregnancy Sciatica may also be experienced in 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. This may also carry on after the baby is born. |
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The Problem Isn't Always Where It Hurts...Sciatica
The term sciatica originated from the nerve associated with the problem. Sciatic Nerve is the main nerve supply of the lower limbs. The sciatic nerve originates from the nerve roots L4, L5 and S1, S2 and S3. By this or that reason when any of these nerve roots, is compressed or irritated; the person will feel abnormal sensation in the area of its supply. E.g. in involvement of the L4 - L5 spinal nerves; the fellow will experience pain inside of calf and top of foot. Similarly other parts of the lower limb are involved according to the affected nerve root.
If same is happening with you; it is clearly indicating that you should take necessary action to restore the normal curvature and functioning of the back bone. These symptoms might confuse you as there are possibilities that you think there is some problem in your lower limb otherwise it is okay; problem is in your back not in your lower limb. It is some thing like; you are not having electric supply in your main supply and lights are off on rooms. Here you should not think that the problem is in the room; it is in the main supply……….
To Know
What to do to restore the normal curvature and functioning of the back bone
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Diagnosis
 Because of the many conditions that can compress nerve roots and cause sciatica, treatment and symptoms often differ from patient to patient. Some common indicators of sciatica are numbness in the feet or legs, strange sensations, impaired reflexes, and weakness. Diagnostic tests can come in the form of a series of examinations by a physician. Patients will be asked to adopt numerous positions and actions, such as squatting, walking on toes, bending forward and backward, rotating the spine, sitting, lying on the back and raising one leg at a time. Increased pain will occur during some of these activities.
Sciatica might be revealed by a neuromuscular examination of the legs by a physician. There may be weakness of knee bending or foot movement, or difficulty bending the foot inward or down. Pain down the leg can be reproduced by lifting the leg straight up off the examining table.
 To further confirm the diagnosis an Imaging is advised. Imaging may include either CT or MRI. Imaging methods such as MR neurography may help in diagnosis and treatment of sciatica. MR neurography has been shown to diagnose 95% of severe sciatica patients, while as few as 15% of sciatica sufferers in the general population are diagnosed with disc-related problems. MR neurography is a modified MRI technique using MRI software to provide better pictures of the spinal nerves and the effect of compression on these nerves. MR neurography may help diagnose piriformis syndrome which is another cause of sciatica that does not involve disc herniation.
Tests are guided by the suspected cause of the dysfunction, as suggested by the history, symptoms, and pattern of symptom development. They may include various blood tests, x-rays, MRIs, or other tests and procedures.
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Causes of Sciatica
