An adult vertebral column (backbone or spine) consists 26 bones called vertebrae. These are:

in the neck region - 7 cervical vertebrae

in the chest region - 12 thoracic vertebrae

supporting the lower back - 5 lumbar vertebrae  

fused together into one bone called sacrum - 5 sacral vertebrae

fused into one or two bones called coccyx - 4 coccygeal vertebrae

Before fusion of the coccygeal and sacral vertebrae, the total numbers of vertebrae are 33. In between the vertebrae are soft disks filled with a jelly-like substance. The disks are protective shock-absorbing pads between the bones of the spine and keep the vertebrae in place. When a disk between two bones in the spine presses on the nerves around the backbone, it's called a herniated disk. The slipped disc is also herniated disk, bulging disk, compressed disk, herniated intervertebral disk, herniated nucleus pulposus, prolapsed disk or ruptured disk.

Factors that lead to injury from a slipped disk include aging with associated degeneration and loss of elasticity of the discs and supporting structures, improper lifting, especially if accompanied by twisting or turning and excessive strain.

A slipped disk can produce varying degrees of pain: - For slipped disks in the neck: numbness, tingling, weakness, or pain in the shoulder, neck, arm, or hand, upper back, hands get real cold. Sometimes the disk can push on the spinal cord and cause symptoms all over;

- For slipped disks in the lower back: muscle spasms, numbness, tingling, weakness, or pain in the buttocks, back, legs, or feet, numbness and tingling around the anus or genitals, pain down the back of each leg from the buttocks to the knee (this is called sciatica), pain with movement, straining, coughing, or doing leg raises, difficulty controlling bowel movements or bladder function.

The pain from a herniated disk is usually worse when you're active and gets better when you're resting. Coughing, sneezing, sitting, driving and bending forward may make the pain worse. The pain gets worse when you make these movements because they put more pressure on the nerve. People with painful herniated disks often try to change positions to reduce the pain. You may have found that holding yourself up with your hands while you are sitting helps the pain. Shifting your weight to one side may also help Herniated disks are most common in the lumbar spine (L2, L4, L5, L6), the part of the backbone between the bottom of the ribs and the hips, but they appear on the cervical (c4,c5, c6, c7) and sacral spine (S1, S3). Herniated disc (Page 2)