What is a spinal disc bulge/herniation?

​When you’ve visited your doctor and they tell you there is a bulging disc in your back, what is that? Perhaps you’ve been told you have a protruding disc or a herniated disc? In this article you are going to learn what each of terms mean. 

What is a disc?

​To begin, you’re going to need to know what a disc is in the first place. A disc is the object that lives between the vertebrae in your spine. They can be thought of as a jelly donut; they have a firm fibrous outside layer called the annulus fibrosus with a jelly in the middle. The jelly in the middle is called the nucleus pulposus. 

(Adapted from Asher, 2019)

What is a disc bulge?

A disc bulge is basically what it sounds like, it's a bulge in the spinal disc. Almost always these bulges occur in a direction towards the back of the body (posteriorly), not the front. 

On the right side of the image there is a bulge pushing backwards towards the nerves. The outer part of the disc - the annulus - is still intact, there is no escape of the inner jelly (nucleus pulposus)

(Adapted from Ravenswood Chiropractic and Wellness Center n.d.)

What is a disc herniation?

(Adapted from Ravenswood Chiropractic and Wellness Center n.d.)

A disc herniation essentially occurs when the jelly has been pushed out of the donut (when the inner nucleus has pushed through the outer annulus). The jelly that has pushed out of the donut is still attached to the jelly inside the donut.

Disc herniations are further broken down into a disc protrusion and a disc extrusion, which describes the shape of the herniation. Understanding the shape of a disc herniation isn't really important for this conversation, so we won't discuss it here. 

---

What is a disc sequestration?

 A disc sequestration (or sequestered disc) occurs when some of the jelly (nucleus) has separated from the jelly inside the donut and is now loose outside of the donut (disc). This means there is a free fragment of material that has separated. 

(Adapted from Ravenswood Chiropractic and Wellness Center n.d.)

Asher, A. (2019, November 4). How to Keep Your Intervertebral Discs Healthy. Retrieved January 11, 2020, from https://www.verywellhealth.com/the-intervertebral-disk-296561.

Ravenswood Chiropractic and Wellness Center (n.d.). Disc Herniation. Retrieved from https://www.rennwellness.com/wp-content/cache/all/disc-herniation.html/index.html.
​

---