Herniated Discs
When people say they have a "slipped" or "ruptured" disk in their neck or lower back, what they are actually describing is a herniated disk - a common source of pain in the neck, lower back, arms, or legs.
Anatomy
Disks are soft, rubbery pads found between the hard bones (vertebrae) that make up the spinal column. The spinal canal is a hollow space in the middle of the spinal column that contains the spinal cord and other nerve roots. The disks between the vertebrae allow the back to flex or bend. Disks also act as shock absorbers.
Disks in the lumbar spine (low back) are composed of a thick outer ring of cartilage (annulus) and an inner gel-like substance (nucleus). In the cervical spine (neck), the disks are similar but smaller in size.
Cause
A disk herniates or ruptures when part of the center nucleus pushes through the outer edge of the disk and back toward the spinal canal. This puts pressure on the nerves. Spinal nerves are very sensitive to even slight amounts of pressure, which can result in pain, numbness, or weakness in one or both legs.
Risk Factors/Prevention
In children and young adults, disks have high water content. As people age, the water content in the disks decreases and the disks become less flexible. The disks begin to shrink and the spaces between the vertebrae get narrower. Conditions that can weaken the disk include:
Improper lifting
Smoking
Excessive body weight that places added stress on the disks (in the lower back)
Sudden pressure (which may be slight)
Repetitive strenuous activities
Symptoms
Low back pain affects four out of five people. Pain alone is not enough to recognize a herniated disk. See your doctor if back pain results from a fall or a blow to your back. The most common symptom of a herniated disk is sciatica - a sharp, often shooting pain that extends from the buttocks down the back of one leg. It is caused by pressure on the spinal nerve. Other symptoms include:
Weakness in one leg
Tingling (a "pins-and-needles" sensation) or numbness in one leg or buttock
Loss of bladder or bowel control (If you also have significant weakness in both legs, you could have a serious problem and should seek immediate attention.)
There are numerous mechanical causes of back pain including:
Spondylosis : (Osteo-Arthritis) : Spinal disease, associated with degenerative discs.
Facet Joints (or Zygapophyseal Joints) : Each vertebral body has four facet joints.
Bones and Ligaments Osteophytes : Bone spurs affecting blood supply to the vertebra.
Spondylosis Symptoms : Spondylosis may affect cervical (neck) or lower (lumbar) spine.
Spondylolisthesis : Spondylolysis with a forward translation of the vertebra.
Back Strain or Back Sprain : Pulled back muscles, caused by overloading or overuse.
Sciatica: Travelling back, buttock & leg pain, tingling, numbness or weakness.
Spinal Stenosis : Narrowing of the spinal canal, causing pressure on the spinal cord.
Herniated Discs : Slipped discs occur when a spinal disc splits or ruptures.
