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. It may help to think of them as miniature jelly doughnuts, exactly the right size to fit between your vertebrae.
A bulging disk extends outside the space it should normally 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 its bun. The part of the disk that's bulging is typically the tough outer layer of cartilage. Bulging usually is considered part of the normal aging process of the disk.
A herniated disk, on the other hand, results when a crack in the tough outer layer of cartilage allows some of the softer inner cartilage to protrude out of the disk. Herniated disks are also called ruptured disks or slipped disks.
Bulging disks are more common and usually cause no pain. Herniated disks are more likely to cause pain, but some cause no pain whatsoever.
Randy A. Shelerud, M.D.
Feb. 08, 2014
- Herniated disc. American Association of Neurological Surgeons. http://www.aans.org/Patient%20Information/Conditions%20and%20Treatments/Herniated%20Disc.aspx. Accessed Aug. 14, 2013.
- Low back pain in adults. http://www.uptodate.com/home. Accessed Aug. 14, 2013.
- Daroff RB, et al. Bradley's Neurology in Clinical Practice. 6th ed. Philadelphia, Pa.: Saunders Elsevier; 2012. https://www.clinicalkey.com. Accessed Aug. 14, 2013.
- Firestein GS, et al. Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. http://www.clinicalkey.com. Accessed Aug. 14, 2013.