Numb Bums and Back Pain – What is Sciatica?

Sciatica seems to be a well known but poorly understood condition.

It generally refers to pain in the buttock and back of the leg, but can also include back pain, tingling, shooting pain, numbness and muscle tension.

Sciatica is a result of irritation to the sciatic nerve.  The sciatic nerve is the longest and largest nerve in the human body; about the width of a pencil in places and stretches from the low back down to the tip of your toes.

Your sciatic nerve supplies your skin, muscles and joints in the back and side of your leg, so these structures are affected when the nerve is irritated.  This is what causes tingling and numbness (sensory fibres supplying your skin) and muscle tension (motor fibres supplying your hamstrings and calf).

So what causes sciatica?  The two most common causes are a problem with the intervertebral discs in your low back and tension in the piriformis muscle in your buttock.

Your discs act as cushions between your vertebrae (bones in your spine).

If they become damaged or irritated (sometimes referred to as a slipped disc) they can cause low back pain and sciatica.  This may be because they start squeezing on part of the sciatic nerve, or because inflammation in the low back is irritating the nerves.

Either way, the sciatic nerve can become very sensitive and start to cause painful symptoms.

There is a muscle deep in the buttock called piriformis.  In many people the sciatic nerve emerges through or underneath this muscle before continuing its journey down your leg.  If piriformis becomes too short and tense it can squeeze the sciatic nerve and eventually lead to sciatica.

There are various potential causes of disc problems and piriformis syndrome which are too long to go into here!

Those are just the 2 main causes of sciatica.  There are other causes, some of which are quite serious conditions such as tumours or infections around the spine.  Thankfully they are pretty rare but it is sensible to seek professional attention if you have back pain or sciatica.

Sciatica is easily confused with other conditions.   Issues with the low back, sacroiliac joints (in the pelvis), hip and knee can cause similar symptoms.  I always take a thorough case history and examination so I can work out what I think is causing the problem.  Then an appropriate treatment plan can be formulated, or I can refer to another therapist or your GP if necessary.