Separating each spinal vertebra is a disc. Its fibrous outer ring holds in a jelly-like material. Because of the way a disc attaches to the spinal bones above and below it, it can't actually "slip." However, a disc can bulge, tear, herniate, thin and collapse. But it can't slip.

When I ask most people in Cedar Rapids this, most think it protects the patient from the doctor's germs. But it's so porous it does little to prevent the passage of germs. We chiropractors don't bother with masks.