What is Sciatica

Understanding Sciatica

Sciatic Neuralgia, commonly known as sciatica, is a sharp pain felt along one of the 2 sciatic nerves. Located at the rear of each of the legs, these are the largest nerves in the body (see diagram below). They join the spine lower back, at the height of the lumbar and sacral vertebrae (just above the coccyx).

Sciatic Nerve Diagram

The pain reaches primarily the buttock and thigh, and often extends to the foot. Most often, the pain affects only one side of the body. In the case of low back pain, “kidney tour” or of “lumbago”, the pain is usually located at the bottom of the back and buttocks.

It is of variable intensity and can limit movements.

In the case of sciatica, pain is usually felt to one side of the body, in one buttock only and pain is felt throughout the leg down to the foot. Sometimes pain is also felt at the bottom of the back.

Intense back pain

Causes of Sciatica


Sciatica is not a disease in itself. It is the sign that the sciatic nerve is irritated. The majority of cases are due to a herniated disc coming to compress one or other of the 5 roots of the sciatic nerve. Symptoms vary slightly, depending on the affected root. (The root is the part of the nerve that joins the spinal cord within the spinal column.)

Sciatica may also be attributable to one or other of the following factors:

Narrow lumbar Canal (spinal stenosis)

A narrowing of the canal (which are inserted into the nerves) can cause a compression of the nerve roots in lumbar region, and sciatica. This occurs mainly in elderly people.

Piriformis syndrome

It is caused by inflammation of a basin called piriformis muscle (it has the form of a PEAR) or pyramid. If this muscle is contracted and swollen, it can exert pressure on the sciatic nerve and irritate it. Athletes and people who train improperly are more susceptible to this condition.

Facet syndrome

This syndrome arises from the facet joints, thin joints located at the top and at the bottom of each vertebra (not to be confused with intervertebral discs, another structure which allows the articulation of the vertebrae). Poor posture or a false move can create a slight misalignment of these facets. Pain in the back and sometimes sciatica may ensue.



A fall, a car accident or any other situation resulting in a blow to the back can cause injury to the nerve roots.

Other causes

Osteoarthritis or metastases that would put pressure on the sciatic nerve can cause back pain and, more rarely, sciatica. These two situations occur especially in the elderly.


In the majority of people suffering from sciatica, symptoms subside within 4 weeks.

However, it often tends to reappear if nothing is done to prevent it. Sciatica may also be associated with a problem of chronic low back pain.

When should I consult?

When symptoms akin to those of a sciatica declare themselves, it is best to consult a doctor for an accurate diagnosis. If it is sciatica and treatments fail to relieve the pain or that it intensifies, consult a doctor again.

Consult a doctor in emergency if:

The back pain is intense as to be hardly bearable; sciatica symptoms are accompanied by urinary or fecal incontinence (or retention), impotence, loss of sensitivity in the region inside thighs and perineum or a fix to stand or climb stairs.

In addition to the symptoms of sciatica, a rapid and unexplained weight loss occurs.

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