Sciatica

Sciatica is the name for a syndrome which is characterised by pain that radiates along the path of the sciatic nerve, the longest and largest nerve in the body. It then travels from your lower back through your hip and buttock and down your leg where it pides into two branches at the knee.

One of the most common causes of sciatica is a herniated disk. Herniate means bulge or stick out. Intervertebral disks are the spongy disks that form a cushion between the vertebrae of the spine. The disks have a strong outer layer made of cartilage, with a soft gelatinous centre that acts as a shock absorber. If the outer layer of the disk becomes weak, through age or injury, the soft centre can bulge out through the weakness — this is what’s known as a herniated or ruptured disk.

If any of the 5 pairs of nerve roots that form the origin of the sciatic nerve are compressed in the spine by a ruptured disk they can give rise to pain down the sciatic nerve. Not only does a herniated disk press on the nerve root, but chemicals leaking from the soft centre of the disk irritate the nerve root, causing inflammation.

Bone spurs or osteophytes are bony outgrowths on the edges of joints. Bone spurs are not painful in themselves, but unfortunately, the bone spurs can rub on nearby bone or nerves, causing problems. In the spine, bone spurs can intrude into the space normally reserved for the nerves, thus causing sciatica.

Piriformis syndrome is an uncommon cause of sciatica. The piriformis is a muscle that lies deep underneath the gluteal muscles of the buttocks. The function of the piriformis muscle is to externally rotate and stabilise the hip. The sciatic nerve passes directly underneath the piriformis. Piriformis syndrome occurs when the piriformis muscle becomes tight, goes into spasm, or swells.

Stenosis means narrowing, and lumbar spinal stenosis is narrowing of the spaces carrying nerves in the lumbar spine. The resultant narrowing of the lumbar spinal canal squeezes the nerves, which may cause back pain, pain down the sciatic nerve and weakness of the leg muscles. If you have lumbar spine stenosis it is likely you will have back pain most of the time, and leg pain and numbness start when you begin to walk.

The changes in centre of gravity and therefore on the position of the lumbar spine with pregnancy can be a cause of pressure on the sciatic nerve. Sciatica can also  be caused by tumours impinging on the spinal cord or the nerve roots.

Chiropractors get great results helping with sciatica in most cases.  They first work to establish the cause of the problem. Ifthe problem is mechanical in nature they use manual techniques to correct the problem. If the problem is not mechanical then they will refer to the appropriate person.