Sciatica

Sciatica is the name given to any sort of pain that is caused by irritation or compression of the sciatic nerve.
The sciatic nerve is the longest nerve in your body. It runs from the back of your pelvis, through your buttocks, and all the way down both legs, ending at your feet.
When something compresses or irritates the sciatic nerve, it can cause a pain that radiates out from your lower back and travels down your leg to your calf (see Sciatica – symptoms for more information). Sciatic pain can range from being mild to very painful.
A slipped disc is the most common identified cause of sciatica, but in some cases there is no obvious cause (see Sciatica – causes for more information).

Types of sciatica

There are two types of sciatica:

• Acute sciatica, which lasts up to six weeks
• Persistent (chronic) sciatica, which lasts longer than six weeks

Most cases of acute sciatica will pass without the need for treatment. A combination of self-help measures such as over-the-counter painkillers, exercise and hot or cold packs can usually relieve the symptoms.

For persistent sciatica, you may be advised to try a structured exercise programme under the supervision of a physiotherapist. In very rare cases, surgery may be needed to control the symptoms.

Outlook

Most people find their sciatic pain goes away naturally within a few days or weeks. However, see your GP if:

• you experience any other symptoms together with your back and leg pain, such as weight loss or loss of bladder or bowel control
• You experience increasingly more pain and discomfort
• Your pain is too severe to manage with self-help measures
• In these cases, your GP should check whether there is a more serious problem causing your pain.

How The Spine Works

 Your spine extends from your skull to your pelvis. It is made up of 24 individual bones called vertebrae, which are stacked on top of each other.

• The front of each vertebra is solid and is called the vertebral body. Behind the body of each vertebra is an arch of bone called the lamina. 
• The arches form a hollow channel known as the spinal canal or vertebral canal, which protects the spinal cord and nerves. 
• A pair of spinal nerves branch out (one to the left and one to the right) from each vertebra. 
• These nerves are called nerve roots and pass through gaps in the arches where they join up to provide sensation and movement to parts of the body. 
• The gaps are called foramens. 
• The vertebrae are separated by soft pads or discs that act as shock absorbers. 
• Each vertebra also has two sets of joints called facet joints which, with the discs, allow the spine to bend. The nerve root foramens are covered by the discs at the front and the facet joints at the back. 
• The vertebrae are also held together by tough bands called ligaments. 
• Together with the spinal muscles, these give the back its strength.