Pain Flare

The most common types of personal injury cases we encounter are those involving herniated or bulging intervertebral discs. If you are unfamiliar with intervertebral disc anatomy and disc injury, please read on.

The intervertebral discs (figure A) are like small cushions, or shock absorbers, that fit between the vertebrae that make up the spine. These discs (figure B) are composed of a gel-like center, the nucleus pulposus, surrounded by a tough fibrous outer cover, the annulus fibrosus.

Figure A

As long as the annulus is undamaged, the disc can effectively absorb the impacts of normal daily activity and provide flexibility to the spine. However, if the annulus becomes thin or weak, the nucleus may bulge outward (Figure C) toward the spinal cord and/or nerve roots. This is called, straightforwardly enough, a disc bulge, or sometimes a disc protrusion.

If the annulus is completely torn and the nucleus herniates out through the tear, it is officially termed a disc herniation, or sometimes a disc extrusion, or, colloquially, a ruptured disc (Figure D). Occasionally, medical experts, and even some textbooks, use the term “disc herniation” to refer to a bulge, so make sure that you and your expert are in agreement over the terminology before proceeding to deposition or trial.

Figure B Figure C Figure D

The difference between a disc bulge and a disc herniation is not one of severity or pain, but whether or not the nucleus remains contained inside the annulus. Inside = bulge. Outside = herniation. The pain from either of these injuries ranges from zero to excruciating, depending on how the disc material impacts the spinal cord and/or nerve roots. If the disc directly impacts the spinal cord, the resulting compression can cause pain on one side of the body, or both sides. A disc that protrudes toward the side and compresses only one nerve root will only cause pain on that side of the body. Radiating pain resulting from the compression of one of these nerve roots is called radiculopathy. Spinal cord or nerve root compression can also lead to other symptoms such as bladder and bowel incontinence or sexual dysfunction.

These are some of the basics of intervertebral disc anatomy and types of disc injuries. You can see hundreds of images depicting these problems on our web site at or feel free to drop me a line.

Benjamin B. Broome, M.A.
Vice President of Medical Content
Medical Legal Art
1275 Shiloh Rd NW Suite 3130
Kennesaw GA 30144

Benjamin B. Broome, M.A.