Herniated and Bulging Discs

A Spine Specialist Answers Common Herniated Disc Questions

Some people develop a herniated or bulging disc in their neck or back. Injury, aging, and poor lifestyle choices may increase the risk for a disc problem. Below, several common questions about disc problems are answered.

Do Intervertebral Discs Slip?

Illustration of a herniated discIn lay terms, a slipped disc can mean a ruptured disc or herniated disc. Although the term "slipped disc" is used, discs do not slip. Each intervertebral disc is sandwiched between two vertebrae supported by a system of ligaments that help hold the spinal package together.  An intervertebral disc cannot slip, so when you hear the phrase "slipped disc," realize that bulging disc or herniated disc is the more proper term.

What Is the Difference Between a Bulging and Herniated Disc?

Intervertebral disc disorders are "contained" or "non-contained." A bulging disc is an example of a contained disc disorder.

Bulging Disc
A bulging disc has not broken open; the nucleus pulposus remains contained within the annulus fibrosus . A bulging disc could be compared to a volcano prior to eruption and may be a precursor to herniation. The disc may protrude into the spinal canal without breaking open. The gel-like interior (nucleus pulposus) does not leak out. The disc remains intact except a small bubble pops out attached to the disc.

Herniated or Ruptured Disc
A non-contained disc is one that has either partially or completely broken open, and that is a herniated or ruptured disc. To illustrate, imagine a tube (annulus fibrosus) of toothpaste (nucleus pulposus) placed under pressure (you squeezing it, for example). The pressure causes the toothpaste within the tube to move wherever it can. If any part of the tube is weak, toothpaste may leak out.

When a disc herniates the contents may spread out to the spinal cord and spinal nerves. The disc material has little space to go—and so it may head into the area occupied by the spinal canal and nerve roots.

Why Might a Herniated Disc Cause Pain?

Returning to the leaky tube of toothpaste, the disc's gel-like nucleus contains a chemical that irritates the nerves and can cause them to swell. After the chemical agent has done its job, the remnants of the chemical remain and continue to press on the irritated and swollen nerves.

To complicate matters, sometimes fragments from the annulus fibrosus (tire-like outer disc wall, or the tube in the above example) break away from the disc and drift into the spinal canal. These free fragments may travel in the spinal canal. Depending on the type of injury and the condition of the discs, more than one disc may herniate, rupture, or bulge. Sometimes injury causes a combination of intervertebral disc disorders.

This article is an excerpt from the book Save Your Aching Back and Neck: A Patient’s Guide, edited by Dr. Stewart Eidelson.

Updated on: 11/21/17
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