The spine is made up of small bones called vertebrae stacked on top of each other and these bones protect the spinal cord. The spinal discs which sit in between the bones act as shock absorbers and are made up of a tough fibrous outer layer and a gelatinous inner core.
The term slipped disc refers to a bulging disc, herniated disc, disc protrusion and prolapsed disc and these can all be used to mean the same thing. The term slipped disc can be confusing as the disc itself doesn’t move. Some of the inner gel-like material can leak out if the outer layer develops a crack.
Most discs are well hydrated and the outer layer encases the inner. When discs get older and degenerate they can dehydrate, flatten and the outer layer can crack so some of the inner gel leak out. Problems occur when the leakage presses on nearby nerves and causes symptoms such as pain in one of the legs – like sciatica.