Slipped disc
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Slipped disc (medical term: prolapsed intervertebral disc) is a condition in which, due to a tear in the outer fibrous ring, the central part of the intervertebral disc is protruding into the spinal canal. Most commonly this occurs in the lowermost part of the spine, especially between the fourth and fifth vertebral bodies and between the fifth vetrebral body and the sacrum. This protrusion usually occurs to one side of the spinal canal, at the point where a nerve root leaves the canal. Impingement on the nerve causes pain, numbness and/or weakness in the part of the skin (dermatome) and muscle that are taken care of by the particular nerve root. The pressure on the nerve is not the only cause of the pain. The leaking of chemical substances from the disc lead to an inflammation of the root, also causing pain.
Spondylolisthesis is a condition in which one vertebra slips forward onto the one below it. Retrolisthesis is when one vertebra slips backwards on the one below.
This usually occurs because the facet joints at on the posterior part of the spine have degenerated (worn away) and fail to prevent excessive vertebral slippage. In adults, the most common cause is a degenerative disc disease which leads to excessive stress on the facet joints and causes degeneration(such as arthritis) and the slip usually occurs between the fourth and fifth lumbar vertebrae (L4 and L5) or the one below that level.
Symptoms can include lower back pain, pain in the thighs and buttocks or tenderness in the slipped area. Leg weakness or numbness can result from pressure on nerve roots and can cause pain to radiate down the legs. Other causes of spondylolisthesis include stress fractures (caused by repetitive hyper-extension of the back, commonly seen in gymnasts) and traumatic fractures.
External links
- Herniated Discs (http://www.spineuniverse.com/displayarticle.php/article1431.html)
- Cervical Herniated Discs (http://www.spineuniverse.com/displayarticle.php/article265.html)
- Lumbar Herniated Discs (http://www.spineuniverse.com/displayarticle.php/article28.html)Template:Med-stub