Because the spine is such a complex component of anatomy, it’s no surprise that terminology can be confusing and overlaps. Patients often have to deal with bulging discs or herniated discs. However, it can be confusing to know what these are and how they are distinguished. The two conditions are distinct and warrant different treatment. However, sometimes the terms are interchangeable, which can be misleading.
What is a Bulging Disc and How Does It Work?
The spinal discs are located between the segments of the spine. Spinal discs, which are soft, spongy shock-absorbing devices that protect the spinal cord and make the spine more flexible, are soft, spongy shock absorbers. Each disc is made up of two parts: a jelly-like outer portion and a harder, more protective outer part.
The discs become stiffer and dehydrate as the spine ages. The disc may become compressed or flattened due to this stiffening and dehydration. The disc’s fibrous outer portion may “bulge” into your spinal canal. This can be compared to a hamburger with too many buns. This is normal and not pathological. Although bulging discs can cause nerve compression in the spine canal, they are quite common and don’t often cause symptoms. In the absence of stenosis, a bulging disc rarely needs treatment.
What is a Herniated Disc and How Does It Work?
A herniated disc is when there is an opening in the disc’s outer layer that allows large pieces of the inner disc to escape. Or when the outer layer becomes so thin and stretched that large portions of the inner disc can move into the spinal canal. The first scenario is sometimes called “non-contained”, “extruded”, “free fragment” or “contained fragment” by medical professionals.
A jelly donut is a great way to visualize the differences between a bulging disc or a herniated disc. A slightly flattened bulging disc is similar to a jelly donut. If the jelly oozes out of the donut’s surface, it can become a herniated disc.
What is the difference between a bulging and herniated discs?
Your spine’s discs act as cushions. The outer layer is made up of hard cartilage and the middle is composed of softer cartilage. You can think of them like miniature jelly doughnuts that fit perfectly between your vertebrae. As we age, discs begin to show signs of wear. discs can become dehydrated and their cartilage becomes stiffer over time. These changes can cause the outer disc layer to bulge quite evenly around its circumference, making it look a bit like a hamburger with too many buns.
Although a bulging disc may not affect all of its circumference, it can usually affect at least 25% to 50% of its perimeter. The bulging disc affects only the outer layer, though cartilage. A herniated disc is a condition where the outer cartilage layer cracks allowing some of the inner cartilage to protrude from the disc. Although the entire disc doesn’t rupture or slip, herniated discs can also be called slipped or ruptured discs. The crack only affects a small portion of the disc.
A herniated disc is less likely to cause pain than a bulging one. This is because it protrudes further and is more likely to irritate nerve roots. It can cause irritation by either compression of the nerve, or more often, it can cause painful inflammation of nerve roots. An imaging test may show that your back pain is not caused by a herniated disc. Many people who have MRI evidence of herniated discs have no back pain.
Symptoms: Herniated Disc vs. Bulging Disc
A disc can herniate, causing irritation and/or compression of nearby spinal nerves. Patients with disc pathology report pain and discomfort primarily due to irritation and compression. The severity and frequency of symptoms can vary depending on whether the disc is bulging or herniated.
Both can cause back or leg pain, tingling, numbness and loss of range-of-motion. However, herniated discs are more likely to experience these symptoms. A bulging disc is more likely to contain the disc material than a herniated one, so there is less chance of nerve irritation or compression.
An MRI is the only way to determine if a disc has bulged. However, even if a herniated disc is confirmed by MRI, it might not be the source of your pain. Many people have MRI evidence of herniated or bulging discs, but no pain or discomfort. A physical exam and discussions with your doctor are the best ways to determine the condition of your spine.