Herniated vs. Bulging Disks?
Disks act as cushions between the vertebrae in your spine. They’re composed of an outer layer of tough cartilage that surrounds softer cartilage in the center. A bulging disk extends outside the space it should occupy. The bulge typically affects a large portion of the disk, so it may look a little like a hamburger that’s too big for the bun. A herniated disk results when a tear in the outer layer of cartilage allows some of the inner cartilage to protrude out of the disk. The protrusion of inner cartilage in a herniated disk usually happens in one distinct area. Herniated disks are also called ruptured disks or slipped disks.
Mayo Clinic, November 2013