FAQs

What is the difference between a herniated disc and a bulging disc?

Dr. Mark R. McLaughlin
Princeton, NJ
A normal healthy disc sits between two vertebral bones that form part of the spinal column and acts like a shock absorber. When a disc becomes worn down, its size shrinks and the neck joint it makes up becomes loose. When that happens, the vertebral bones can come close to each other and rub while the outer envelope of the disc buckles due to a loss in size. This envelope sags or buckles much like the waistline of a person's pants after they have gained weight. This buckling of the disc envelope represents a bulging disc.
Dr. Sebastian Lattuga
Rockville Centre, NY
The difference is merely one of degree. In a herniation, more of the annulus is injured allowing for a further or larger deformity of the shape of the disc, i.e., it protrudes out further.
Dr. Moe R. Lim
Chapel Hill, NC
A disc bulge occurs when the covering of the disc becomes stretched and bulges out. A disc herniation occurs when the covering of the disc ruptures and the internal contents of the disc spill out.
Dr. David S. Baskin
Houston, TX
A herniated disc exists when the outer fibers surrounding the disc are disrupted, and a piece of the inner portion comes out through the outer fibers. The herniation is significant when this piece puts pressure on nerves, and produces pain. A bulging disc simply means that the fibers are stretched, and that the disc bulges out beyond the confines of the bone. In this case, the containing outer fibrous fibers themselves remain intact.
Dr. W. Christopher Urban
Glen Burnie, MD
Loss of the normal structural integrity of the intervertebral disc can lead to either a bulging or herniated disc. Bulging discs are very common and develop in most individuals as we age. A disc bulge is a diffuse symmetrical swelling of the disc, and is caused by early disc degeneration and collapse. Bulging discs rarely cause symptoms unless associated with spinal stenosis. In contrast, a herniated disc is one in which the outer layer of the disc, called the annulus, is incompetent. Because of this weak surrounding architecture, it is possible for the inner disc material to squeeze out of the disc. Depending on the size and location of the herniated fragment, a patient may or may not become symptomatic. If the herniated disc material were to press against a nerve root, for example, it could cause leg pain or numbness.
Dr. Sean Salehi
Chicago, IL
In a bulging disk, the soft central portion has not completely leaked through the outer layer of the disc.
Dr. Joseph Alexander
Winston-Salem, NC
Once again, the disc itself is composed of two portions, the outer or annular fibers that contain the inner of cushioning material. If the outer fibers actually tear, a piece of the inner material can extrude and put pressure on the nerve roots or spinal cord in the cervical area. On the other hand, the fibers may gradually deteriorate, causing a gentler bulging of the inner discal material. This can, however, in some circumstances, also put pressure on the spinal cord or spinal nerves. Many physicians do use these two terms interchangeably.
Dr. Robert S. Pashman
Los Angeles, CA
A bulging disc is a slight protrusion of the center of the disc (nucleus pulposus) into the spinal canal. In a bulging disc, the outer ring (annulus fibrosus) has not been ruptured.

A disc herniation is a large protrusion of the nucleus pulposus, which has burst through the annulus fibrosus into the spinal canal, invading the surrounding nerves and causing pain in the neck, shoulders or arms.
Dr. Daniel Resnick
Madison, WI
A herniated disc is a disc in which a piece of the nucleus pulposus has actually traveled through the outer ligament. A bulging disc is a much more common finding on MRI scan and is simply a sign of disc degeneration.
Dr. Mark Testaiuti
Haddonfield, NJ
The amount of disc material that is pushed into the spinal canal or nerve passageway (foramen).
Dr. Rick Sasso
Indianapolis, IN
A herniated disc implies that a piece of that disc, as we just talked about, actually comes out of the back covering of the disc and sits into the spinal canal and causes irritation to a nerve. A bulging disc implies that there is not a tear in the back covering of the disc, that what we see is just a bulge in the back of the disc, very analogous to a tire. When you let the air out of a tire, you see bulges that occur on each side of the tire. That happens in discs that start to degenerate. And as a disc degenerates, it bulges. And that is a very, very common finding that we see in all degenerated discs.
Dr. Douglas Slaughter
Mesa, AZ
A herniated disc in the neck is the nucleus pulposa portion of the disc making it to the outer fibers of the annulus or to the spinal canal or nerve root foramina. A bulging disc is a natural bulge of the annulus fibrosis and not the nucleus pulposus.
Dr. Timothy C. Ryken
Iowa City, IA
These terms are used interchangeably and inconsistently. The important issue is whether the disc appears to be disrupted (changed from what we would expect of a normal disc) and is pressing on a nerve causing symptoms.
Dr. Kevin Yoo
Escondido, CA
A bulging disc is a mild variant of a herniated disc or the precursor to a herniated disc. A bulging disc is a small protrusion of disc that is most likely still contained within the covering of the disc and often so small that it does not cause any symptoms. A herniated disc is a disc that has bulged out so much that it has actually ruptured out beyond the covering of the disc and often causes symptoms by pinching nerves or the spinal cord.
Dr. Paul Saiz
Mesa, AZ
Using the jelly doughnut analogy a herniated disc is a piece of jelly that has squirted out of the doughnut. A bulging disc simply refers to a degenerated disc that has lost vertical height but has expanded from front to back causing a bulge.
Dr. Brett Taylor
St. Louis, MO
A human intervertebral disc is surrounded by dense fibrous tissue called the annulus. When the annulus is still intact but the nuclear material in the disc is pushing out toward the nerves, we consider that a bulging disc. When the fibrous tissue covering the disc or annulus is actually torn, nuclear disc material can break through the covering or annulus and directly contact the nerves. This is considered a herniated disc. Please note these terms are frequently used interchangeably and you must discuss the details of your health issue with your doctor after they review your imaging studies.
Dr. Jeffrey C. Wang
Los Angeles, CA
These terms are often used to describe the same situation. A bulging disc is used to describe a disc that is protruding slightly back against the nerve elements but does not appear to be completely ruptured. A disc herniation is used to describe a more serious condition where the disc is either fully ruptured or protruding significantly causing compression on the nerves.
Dr. Dennis G. Crandall
Mesa, AZ
A disk bulge may occur from normal disk settling that occurs with age, or it can be related to thinning of the containing outer fibers of the disk, allowing the nucleus of the disk to “bulge.” A herniation occurs when the nucleus protrudes through the containing fibers and into the spinal canal.
Dr. Allan Levi
Miami, FL
A herniated disc tends to be a more focal displacement of disc material (by way of convention, less than 50% of the circumference of the disc). Bulging discs, on the other hand, are a mild, smooth displacement of the disc space, which tends to be more diffuse and usually occurs over greater than 50% of the circumference of the disc.
Dr. Brian Subach
Atlanta, GA
Normally the annulus of the disc acts as a covering. Bulging discs usually have a weakened annulus while herniation implies a tear in the annulus resulting in a piece of disc material moving out.
Dr. Jeffrey Goldstein
New York, NY
There can be no difference in the amount of pain each one produces. The difference is really in whether or not the cushioning material is completely outside of the cushion or just bulging within the confines of the cushion. But the end result can be absolutely identical and the treatment is often very similar.
Dr. Theodore A. Belanger
Charlotte, NC
A bulging disc is an intact one that protrudes slightly as a result of degeneration. A herniated disc is one that has developed a hole in it and has squirted out some of its soft inner material. If this material is compressing or causing inflammation of a nerve or the spinal cord, it can cause pain, numbness, tingling and/or weakness in the arms or legs. Bulging discs, on the other hand, can commonly be found in people who have no pain, and are considered a normal part of spine aging.
Dr. Randy Davis
Glen Burnie, MD
All discs begin to bulge and degenerate beyond a certain age. It is almost the normal process of aging. It is only when a piece of disc ruptures out through small tears, often in a bulging disc, that it can press on a nerve root and cause a patient to become symptomatic.
Dr. Kambiz Hannani
Los Angeles, CA
Any time a disc ruptures and extends back into the spinal canal, putting pressure on spinal nerves, the term bulging disc or herniation is used. The two terms are used synonymously; however, bulging disc usually refers to a wide but small disc protrusion; a herniated disc refers to a focal (one small area) and larger disc protrusion.
Dr. B. Theo Mellion
Carbondale, IL
There can be no difference in the amount of pain each one produces. The difference is really in whether or not the cushioning material is completely outside of the cushion or just bulging within the confines of the cushion. The end result can be identical and the treatment is very similar.
Dr. John Peloza
Dallas, TX
A bulging disc represents degenerative disc disease. The disc is showing signs of wear and tear. It is losing some of its fluid content and, therefore, it is drying out. As it dries out, the disc tends to decrease in height, or it starts to settle. As it does this, the wall of the disc tends to bulge or buckle outward. It generally bulges in a symmetric manner, much like the side walls of a deflated automobile tire would tend to bulge outward in a symmetric fashion.

A herniated disc, on the other hand, is a specific defect in the disc wall that allows the central portion of the disc to protrude into the wall of the disc or even into the spinal canal. The location of the disc defect is usually specific, but not symmetric. The automobile tire analogy in this case would be a tire that has been damaged by something, such as a rock or a nail, and has a specific defect with a bleb or outpouching of the tire in one spot.

The commentary above recounts the experiences of these physicians. Medtronic invited them to share their stories candidly. Keep in mind that results vary; not every patient's response is the same. Talk with your doctor to learn more about any products that are mentioned above.

It is important that you discuss the potential risks, complications and benefits of spinal surgery with your doctor prior to receiving treatment, and that you rely on your doctor's judgment. Only your doctor can determine whether you are a suitable candidate for this treatment.

Published: May 04, 2007
Updated: April 19, 2010