Allerton Health Centre

Health & Wellbeing

What is Sciatica?

This condition commonly affects people between the ages of 30 to 50.  In most cases symptoms settle within a few weeks or months.

The sciatic nerve is a long, thick nerve, formed from smaller nerves which exit the spinal column between the lower lumbar vertebrae and from sections of the sacrum. It follows a course through the buttocks and down the rear of the thigh. Branches of the sciatic nerve serve muscles and other tissues of the leg and foot.

Sciatica Image


Symptoms vary between patients, depending on the cause of their sciatica. Pain in the lower back and/or leg can be very severe and cause limitations to movement. Pain may be made worse by sitting and/or bending forwards. Pins and needles, numbness or muscle weakness may also be present. Typically, symptoms are experienced on one side only.


Sciatica is most commonly caused by a ‘slipped disc’. Each vertebrae is supported and cushioned by discs. The discs are made from a tough, fibrous case that contains a softer gel-like substance. A slipped disc occurs when the outer part of the disc ruptures (splits), allowing the gel inside to bulge and protrude outwards between the vertebrae. When this presses against the sciatic nerve, it can cause sciatica. Typically only the nerves exiting on one side of the spinal column are affected, hence creating symptoms on that side (and/or leg) only.

Other conditions in and around the spinal column such as degenerated vertebrae can create nerve compression. As a person gets older the discs start to become harder, tougher and more brittle. Inflammation in the area can irritate the spinal nerves and lead to sciatic type symptoms.

As the sciatic nerve courses through the buttock area, compression can be exerted by the piriformis muscle. This leads to a condition called piriformis syndrome. The piriformis muscle requires treatment in order for the symptoms to be relieved.


Clinical assessment by a doctor or trained therapist is the first step to identifying and treating the cause of a particular episode of sciatica.

Diagnosis needs to be focussed on identifying the cause of the nerve compression and/or irritation.  Clinical examination includes simple ‘movement tests’ along with tests of reflexes, muscle activation and skin sensation

A full history of the symptoms together with the patient’s medical history forms an important part of the picture. Depending on the results of the clinical examination the clinician may refer the patient for additional investigations such as x-rays or scans.


Sciatica can be helped on its way with treatment from a physiotherapist or osteopath. Typically such treatments include careful manipulation along with exercise and postural advice.

For milder symptoms where the cause is more muscular in origin, remedial massage can also be an effective treatment. Acupuncture can also be an effective pain relieving treatment.

Article Info

  • Brief:

    Symptoms created by irritation or compression of the sciatic nerve explained.

  • Published on: 29th Jun 2011
  • Written by: Paul Whelan