Q. What is the difference between a bulging disc and a herniated disc?
A. A disc begins to bulge when the center of the disc pushes out against the ligament that surrounds it, much like air being blown into a balloon. Bulging discs are common, and can be seen on MRI even in people who do not have pain. A bulging disc will cause problems when it balloons into the space in the spinal canal.
In comparison, a herniated disc is like a balloon that has popped. The disc herniates when the soft, inner material squeezes its way through ligament tendon and ruptures — like a popped balloon. Pain occurs because of the tear in the ligament, the pressure of the disc material against your nerves, and from the inflammation caused when the inner material is squeezed out of the disc. If there is pressure on a nerve, symptoms of numbness and weakness may also be noticed in the areas supplied by the nerve.