What is sciatica (other than a pain in the bum)?

September 24, 2013 | By More

I have had a run of patients recently complaining of “sciatica” and have spent a good deal of my time explaining what this means and dispelling a few myths.  I thought therefore that it might be helpful to write a post on this common symptom which manifests as pain, pins and needles or numbness running into the gluteal area or down the leg and sometimes as far as the foot. The pain is often described “burning” or “shooting” or as a “numb ache” or “cramping” and it can be patchy – e.g. in the back of the thigh and also in the calf.


1)   Sciatica is a symptom not a diagnosis

Many of my patients come to me for the first session telling me that their doctor has told them that they have sciatica. When I explain that I am going to take a history and carry out an examination to find out the diagnosis / source of the symptoms, sometimes they look at me a bit oddly. In fact one woman recently said “But I told you the diagnosis – it’s sciatica”. This is perhaps the most common misunderstanding about sciatica. Sciatica literally means pain in the hip / leg and there are multiple possible reasons why this can occur. However most commonly when we describe pain as sciatica, we refer to pain along the sciatic nerve. This is the longest nerve in the body and forms in the low back and travels through the gluteal area down the back the thigh and divides into branches in the calf and the sole of the foot.

Sciatic nerve



 2)   The sciatic nerve supplies the skin and muscles in the leg to provide sensation and power


The sciatic nerve, like all other nerves, performs two basic functions: first, it sends signals to your muscles from the brain; and second, it gathers sensory information from the body and passes this back to your brain. More specifically the sciatic nerve provides signals to and from the skin of almost the entire leg thus providing us with sensation. In addition it supplies the muscles of the back of the thigh and the leg and foot – allowing them to contract and have power.


3)   The sciatic nerve can be compressed or irritated

Broadly speaking there are two different categories of sciatica. The first is called radiculopathy and is where there is compression of the nerve or significant pressure on the nerve. This causes alteration of the signals that are transmitted along the nerve. When this happens there is a reduction in the sensation of the skin and / or a reduction in the strength of the muscles that the nerve supplies.

The second broad category is when there is irritation or inflammation of the nerve rather than true compression. When this occurs there is no loss of muscle power but there can sometimes be numbness or altered sensation in the limb.


4) The compression or irritation can be anywhere along the nerve

The compression or irritation of the nerve can be anywhere along the course of the nerve. Most commonly it happens at the point where the nerve forms in the lumbar spine. This is called the nerve root. There are a number of structures in this area that can become swollen or damaged and press against or irritate the nerve. For example a herniated or prolapsed disc can cause pressure against the nerve or inflammation around it can irritate the nerve at this point. There are also lots of other areas where the nerve can become entrapped or irritated. Particularly vulnerable areas are where the nerve passes close to another structure such as muscle or a bony prominence. Either direct compression or irritation of the nerve can cause changes in the way the nerve transmits its signals. This is what causes the pain or altered sensations like pins and needles, tingling or numbness. In some cases, patients find it difficult to describe the altered sensations and simply say that the leg doesn’t feel like it belongs to them or just doesn’t feel normal.


5)   A thorough assessment can determine the type of sciatica and the site of entrapment.

A physiotherapist will take a detailed history and perform a thorough assessment so as to make a diagnosis and determine the cause of the sciatica symptoms. The type of pain and where in the leg it radiates to and the presence or absence of tingling, numbness or pins and needles all give vital information. In addition a neurological examination –testing the skin sensation, muscle power and reflexes will identify whether there is true compression or not. Specific tests of the different interfaces that the nerve crosses on its journey down the leg also help to isolate where the entrapment might be.


6)   In most cases sciatica can be treated effectively without surgery

The majority of patients with sciatica will get better without the need for an operation. An operation is only very occasionally required if there is very significant compression on the nerve – blocking it from transmitting its signals and causing marked weakness in the muscles it supplies. If this is the case, an MRI can be arranged to determine the precise site and extent of the problem and to confirm if surgery is needed.


In most cases, more conservative treatments can help resolve the problems. Physiotherapy exercises and in particular nerve-gliding exercises can be very effective in relieving the pain. What I often see is that as patients improve the pain “retreats” back up the leg gradually. Sometimes if the pain is very severe and is too painful to carry out physiotherapy exercises, medications can be prescribed. Traditional non-steroidal anti-inflammatory medications are often useful for mild nerve pain. However if the pain is very severe then specific medications designed to treat neuropathic (nerve) pain can be prescribed by your doctor. These usually take a week or two to begin to be work but have been shown to be very effective in improving sciatica.


7)   Sometimes chronic pain can develop

In most cases after the compression or irritation of the nerve has resolved, the pain, numbness, tingling or altered sensations disappear. However occasionally, chronic pain can develop. This is where the body continues to produce pain even after the tissue damage has healed. There are many factors that contribute to the development or persistence of chronic pain. I will write more extensively about these in another blog post. For the moment more information on managing chronic pain can be found here.


Do you have sciatica and live in the Galway area? If so, why not call the clinic on 091 727777 to book an assessment with Chartered Physiotherapist – Eoin Ó Conaire. You can also contact us via our contact page


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