Sciatica occurs due to damaged discs in the spine, found in the lumbar region of the body.
The human spine consists of 33 bones or ‘vertebrae’ that are stacked one on top of the other to form the spinal column. Nerve fibres run through the whole of the spine, connecting the brain to each part of the body so that it can send and receive messages.
Vertebrae are held together with discs, which allow the spine to be flexible. Discs are made up of a hard outer casing with a substance inside that has a gel-like texture. Sometimes, a person can experience damage to these discs, where the soft, internal section of the disc bulges out of the external casing. This is known as a herniated disc, or a slipped disc.
A slipped disc may then press on or touch a nerve, which can result in pain around the area of the damaged disc. Sciatica causes pain in the lower back, buttocks and legs, due to a slipped disc and pressure to the nerves in that area of the body.
So, what triggers sciatica and damage to the spine? Here are the most common factors:
• Ageing, when discs often become naturally less flexible
• Poor posture when sitting
• Incorrect manual handling (lifting) techniques (i.e. lifting objects that are too heavy or bending the body awkwardly)
• Being overweight
• Accidents, i.e. in the car or having a fall
• Wear and tear from sports and hobbies
• Pregnancy and childbirth
There are other, much less common and more serious health conditions that may cause sciatica, including:
• Spinal stenosis
• Cauda equina syndrome
• Spinal injury/infection
• Tumour in the spine
For more information on what causes sciatica, see the NHS Choices website.
You may also find the Spine Health website useful, which features an overview of sciatica, explained with an animated video.
Read on to find out more about sciatica symptoms and sciatica treatments available to you that can help manage the pain, including sciatica exercises and physiotherapy.