What are vertebral or spinal discs?

Our spine is composed of a series of rounded bones, called vertebrae, each of which has three bony projections. Two of these bony projections point out on either side of each bone laterally and the third points out to the back, posteriorly. Sandwiched between each of the bones you’ll find what is called a spinal or vertebral disc.

Vertebral discs are composed of layers of cartilage, called the annulus fibrosus, which form a ring that contains a fluid, called the nucleus pulposus. The vertebral discs are held in place by connective tissue, in general, and have additional support provided anteriorly and posteriorly by thick ligaments that run along the front (anterior) and back (posterior) sides of the spine.

What is the function of vertebral discs?

The fluid of the nucleus pulposus that is held within the annulus fibrosus of the vertebral disc creates osmotic pressure. This pressure and the structure of the spinal disc itself create space between each of the vertebra, which protects the nerve roots of the spine from compression by the spinal bones.

The arrangement of the vertebrae alternating with vertebral discs also allows for the movement of the spine. There is space between each of the vertebra created by the squashy disc, so each of the vertebra can move at these joints a small amount. When you add up the small movements at each of the vertebral joints, you have the large amount of total movement that we know as spinal movement.

What can contribute to dysfunction of vertebral discs?

• Genetic predisposition
• Injuries and accidents
• Postural imbalances from work or sport activities
• Aging
• Sedentary lifestyle and obesity
• Sometimes there is no obvious cause

Common dysfunctions of vertebral discs

Bulging disc

A bulging disc occurs when the cartilaginous disc between two vertebrae gets compressed by the bony vertebrae above and below and bulges out in one or more places. A bulging disc on its own may or may not cause pain or interfere with function. However, if the bulge is in the direction of a spinal nerve root, you could be more likely to experience pain from a bulging disc.

Herniated disc

A herniated disc is similar to a bulging disc in that an area of the vertebral disc is pushed out from between the vertebrae above and below. In the case of a herniated disc, the area of the disc that gets pushed out is weakened or damaged in some way. As with a bulging disc, if the herniation gets pushed out in a way that causes it to press on one of the spinal nerve roots, it can cause pain, tingling, numbness or other sensations indicating a dysfunction.

Ruptured disc

In the case of a ruptured disc, the cartilaginous disc actually tears all the way to the nucleus pulposus where the fluid is stored, and the fluid starts to leak out. At this point the vertebral disc starts to lose its capacity to maintain space between the vertebrae because the fluid-filled center, which creates the pressure, has been compromised. The vertebral disc in this case can also press on nerve roots, but additional types of dysfunction are also possible as the bony vertebrae are no longer maintained apart from one another. 

Degenerative disc disease

Degenerative disc disease is a general term that describes the situation when normal deterioration of the vertebral structures during aging leads to a secondary cause of pain. As we age, some amount of deterioration of body structures is normal. With respect to the vertebrae, that deterioration can include drying out and thinning of the vertebral disc, cracking and small tears in the outer wall of the disc, or bone spurs on the vertebrae. All of these signs of deterioration of the vertebrae may occur without leading to pain or a particular dysfunction in the spine.

It is also possible that types of vertebral deterioration can lead, secondarily, to disc dysfunctions like herniated or ruptured disc, or pain. For example, bone spurs created during the process of disc deterioration can press on spinal nerves causing pain. The sources of pain arising from types of disc deterioration are varied, however, and a specific diagnosis would require a visit to an appropriate medical professional. 

Treatment of disc dysfunction varies with each specific situation, so as with any experience of pain or other potential symptom of dysfunction in the body, seek out an appropriate medical professional if you have further questions about vertebral disc dysfunction. The specifics of diagnosis and treatment of vertebral disc dysfunction are beyond the scope of this article. If you’d like to read more about muscle function and dysfunction, read the related posts below.