Sciatica Causes


·         Sciatic pain is usually caused by compression of this nerve at the point where it leaves the spine Damage to the nerve can also cause pain.

·         Sometimes, just sitting awkwardly can cause sciatica

·         Herniated disk/disc prolapse
One of the most common causes of sciatica is a herniated disk. Herniate means bulge or stick out. A herniated or ruptured disk is when a nucleus palposus bulges out through a weakened anulus fibrosus. If any of the 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.

·         Osteophytes

Bone spurs or osteophytes are bony outgrowths on the edges of joints. Bone spurs form where cartilage is worn away (for example in arthritis) and bone is rubbing on bone. In an effort to protect the body, new bone forms on the edge of joints. This is called a bone spur. 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
Piriformis syndrome is an uncommon cause of sciatica. The sciatic nerve passes directly underneath the piriformis. Piriformis syndrome occurs when the piriformis muscle becomes tight, goes into spasm, or swells. When this happens it compresses the sciatic nerve beneath it. In roughly one in 7 people, the sciatic nerve passes through the piriformis instead of underneath it – and these people may be prone to sciatic nerve problems.

·         Lumbar spinal stenosis
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 – leg pain and numbness start when you begin to walk. Spinal stenosis tends to affect older people rather than younger people

·         Spondylolisthesis
In this condition, one vertebra slips forward over the vertebra below it. This distorts the spinal canal and results in the nerve roots of the sciatic nerve being compressed.

In adults, the fourth and fifth lumbar vertebrae (L4 and L5) are most commonly affected, with the L4 vertebra moving forward on the L5 vertebra. Spondylolisthesis usually results from degenerative diseases of the spine, such as arthritis

·         Pregnancy
Pregnancy can be a cause of pressure on the sciatic nerve. Sciatica may also be experienced in late pregnancy, primarily resulting from the uterus pressing on the sciatic nerve, and, secondarily, from the muscular tension and/or vertebral compression consequent to carrying the extra weight of the fetus, and the postural changes inherent to pregnancy.


·         Other causes
Sciatica can be caused by tumours impinging on the spinal cord or the nerve roots.
Trauma to the spine, such as from a car accident, may also lead to sciatica.


~ by pcl4 on September 18, 2008.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: