What is an Intervertebral Disc?

Niki Foster
Niki Foster

An intervertebral disc, or discus intervertebralis, is a structure consisting of fibrocartilage located between the vertebrae, the bones of the vertebral column, or spine. The intervertebral discs serve to hold the vertebrae together, cushion the spine, and allow for spinal movement. Each intervertebral disc forms a cartilaginous joint.

An illustration of a healthy spine and one with spinal osteoarthritis, showing how the disease damages the intervertebral discs.
An illustration of a healthy spine and one with spinal osteoarthritis, showing how the disease damages the intervertebral discs.

There are two main parts to the intervertebral disc, the outer annulus fibrosus and the inner nucleus pulposus. The nucleus pulposus consists of loose collagen fibers within a mucoprotein gel, making for a flexible consistency. The jelly-like consistency of the nucleus pulposus provides shock absorption and flexibility to the spine. The annulus fibrosus consists of layers of fibrocartilage, and provides protection and shape to the intervertebral discs.

The intervertebral discs cushion the spine.
The intervertebral discs cushion the spine.

There are a total of 23 intervertebral discs in the human spine. With the exception of the joint between the first two bones of the spinal column, the atlas and the axis, each of the bones in the spinal column is separated by a vertebral disc. The joint between the atlas and the axis allows for a different type of movement than the other vertebral joints, namely, the swiveling movement of the neck. The atlas is a ring shaped bone that circles the conical axis.

Problems with intervertebral discs can lead to a loss of reflexes.
Problems with intervertebral discs can lead to a loss of reflexes.

There are a number of medical problems that can affect the vertebral discs. A prolapsed disc, also called a spinal disc herniation or a slipped disc, is a medical condition in which the nucleus pulposus is forced out of the center of the intervertebral disc through a tear in the annulus fibrosus. A prolapsed disc can lead to pain, numbness or tingling similar to that of a limb that has "fallen asleep," muscular weakness, paralysis, or damaged reflexes. However, depending upon the location of the prolapsed disc, there may be no symptoms at all.

Disc herniation involves the rupture of the material that separates the vertebrae in the spine.
Disc herniation involves the rupture of the material that separates the vertebrae in the spine.

Prolapsed discs often heal on their own, though in severe cases, surgery may be required to repair the intervertebral disc. Surgery is typically a last resort. Spinal disc herniation can be treated more conservatively with anti-inflammatory pain medication or steroids, physical therapy, and lifestyle modification such as weight loss and quitting smoking.

Another medical condition affecting the intervertebral discs is degenerative disc disease (DDD), in which the nucleus pulposus dehydrates as one ages. Intervertebral disc dehydration is a normal part of the aging process, and only some people experience adverse symptoms associated with it. Such symptoms can include pain, tingling, weakness, and impaired movement. Degenerative disc disease may be treated with physical therapy, chiropractic, pain medication, or, in severe cases, surgical intervention.

Invertebral discs hold the vertebrae together.
Invertebral discs hold the vertebrae together.
Niki Foster
Niki Foster

In addition to her role as a wiseGEEK editor, Niki enjoys educating herself about interesting and unusual topics in order to get ideas for her own articles. She is a graduate of UCLA, where she majored in Linguistics and Anthropology.

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Discussion Comments


Does anyone know if degenerative disc disease is something that is hereditary or is it more commonly associated with the aging process?

Several members of my family have had problems with their back. Most of the time this seems to happen around 40 years old and continues to get worse over time.

I have some family members who live with a lot of back pain because they don't want to have surgery. This is something I would really like to avoid happening to myself.

I suspect if someone lives long enough they will have some kind of degenerative disease, but I would think you would have better quality of life than this in your 40's.

I try to keep my weight down, and wonder if there are other things I can do to prevent having cervical intervertebral disc problems.


The alignment of the discs along our spine can play a big part in our overall health. I see a chiropractor on a regular basis just to keep my body and spine aligned.

I began seeing her because I was experiencing back pain when I got out of bed in the morning. Even after getting a new mattress, I still continued to have back pain.

My chiropractor told me that almost every person she treats has some kind of lumbar disc problem. The L5 position, which is part of the lower back, is where she sees more problems than anything.

At every treatment she checks my spine and marks the places that need adjusting. I feel much better after this regular treatment and hope I am doing what I need to prevent cervical disc problems in the future.

If possible, I would much rather try to prevent intervertebral disc disease than try to treat it after the fact.


My husband has suffered from a herniated intervertebral disc and this is something that is very painful and debilitating.

He woke up one morning and could not even get out of bed. All he knew was his back and right leg were really hurting, but had no idea what was going on.

When he was able to get to the doctor, they did x-rays and found out he had this herniated disc.

Initially he took some pain medication, but what helped him more than anything was weeks of physical therapy. He is still supposed to perform some of these exercises at home on a regular basis.

Until you suffer from this kind of back pain, I think it is hard to realize how much this affects your life. He is thankful that the physical therapy made a difference as he really didn't want to go through surgery.

This has made him a lot more aware of how he moves and what he lifts. He no longer picks up something heavy without deciding whether it is worth the risk of hurting his back or not.

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