These discs provide cushioning between each bone and permit the neck, spine and tail to bend, allowing changes in position and posture. Above the discs and running through the bony vertebrae is the spinal cord, which is made up of a mass of nerve fibers that run back and forth between the brain and the rest of the body. As a disc becomes weaker with age or trauma, it may rupture, or herniate, causing a portion of the disc to protrude upward and place pressure on the spinal cord. This pressure typically prevents or inhibits nerve transmission along the spinal cord. The effect on the spinal cord will depend on the amount and severity of the pressure.
Effects can include pain, weakness and paralysis.
A disc herniation in the neck area may affect the entire body, while one in the middle of the dog s back may only affect the actions of the rear legs and abdominal organs. Dog with very long backs, such as dachshunds and Basset hounds, understandably have a greater incidence of disc disease in the middle of the back. In fact, This is the area most often affected in all dogs, regardless of the length of the dog s back. It seems that this area formed at the union of the chest and abdomen, suffers from the greatest amount of torsional stress and is more prone to injury. In most cases we never find exactly when or what caused the disc to rupture.