Here at City Centre Chiropractic in Brisbane, if we had a dollar for every time someone said they had "slipped a disc" we would be rich; however the anatomy tells us differently.
Discs are small pads of cartilage with a pulpy center positioned between each vertebra, that act as shock absorbers or maybe more appropriately shock distributors for your spine. They attach to the weight bearing surfaces of adjacent vertebra in such way that they cannot slip. However they can certainly be damaged with incorrect wear patterns or trauma and so when people refer to a slipped disc they usually mean a torn, bulging or herniated disc. An MRI is the best form of imaging to diagnose a disc problem.