Which Type of Disc Bulge Do You Have?
Find out which type of disc bulge you have so you can make the correct steps forward in your recovery.
There are three categories of disc bulges. Understanding which type of disc bulge you have is important to take the most optimal steps forward in your recovery.
1. Small Focused Bulge
The first and most common type is a focused disc bulge. This is caused by repeatedly bending your spine in the direction away from the bulge. For example, if the bulge is on the posterior side of your disc and towards the right side then bending forward and to the left would promote the bulge (see my article here for a thorough breakdown of how and why bending leads to disc bulges).
People with this type of bulge generally can perform a certain number of tolerable bends before their pain occurs. The more load that is involved in bending (e.g. bending over to pick up something heavy), the less tolerable bends you can perform before the onset of symptoms.
To recover from this type of bulge you need to stop aggravating the bulge and allow it to shrink down in size. Learning to spare your spine and bend with your hips are important strategies to avoid aggravating this type of bulge and allow it to heal. Again, see my previously mentioned article for a more detailed breakdown of this pathology and the strategies to recover.
2. Reduced Disc Height
A different type of bulge can occur when a disc loses height. It is common for disc to lose height following certain injuries (such as damage to a vertebral endplate). Rather than the above type of bulge that only bulges out in one small location, reduced disc height can cause a disc to bulge out on all sides. Imagine letting some air out of a car tyre causing the flattened tyre to bulge under the weight of the car.
Another key difference between this type of bulge and a focused bulge is that bending does not promote this bulge. Instead, applying compression ("squishing" force) will cause the disc to bulge on all sides. For example, if you are carrying shopping bags or lifting something over your head this will add some compressive force to your spine. You can again imagine a car tyre that has had some air taken out of it. If you held this tyre up in the air it wouldn't be obvious that air had been taken out of it. However, the empty space inside the type will compress causing it to bulge under the weight of a car.
We can again continue with our tyre analogy to understand the consequences this type of bulge has. What does it feel like to drive a car with a flat tyre? You feel a bit unstable on the road, like you are not in complete control. The same thing is occurring in your spine. A flattened disc can cause instability and increased motion in your spine leading to pain. Symptoms can vary with this type of bulge and include central back pain as well as pain down different legs.
With this type of bulge, we need to identify the activities causing symptoms and eliminate them to get out of pain. Then we can build pain-free movement patterns and train improved stiffness and control.
3. Disc Tear
The third and final type of disc bulge is an annular tear. Our annulus is the outer ring of our discs that contains the gel like substance within the discs centre. The annulus is made up of concentric rings of collagen that are woven together into a biological fabric. The many layers of this fabric can separate which allows the gel substance from the middle of the disc to leak into the spaces between the layers.
This type of bulge usually occurs with excessive twisting motions. To recover it is important to avoid twisting and with time the disc annulus will heal, and symptoms will reduce. The McKenzie side glide exercise can be effective in treating this bulge and reducing symptoms, however if significant height has been lost from the disc than it is often ineffective. If you are not noticing significant improvement after performing a side glide, it may be best avoided.
Frequently Asked Questions
What are the different types of disc bulge?
There are three main categories. A small focused bulge is the most common — caused by repeated bending, it protrudes in one localised direction. A reduced disc height bulge occurs when a disc has lost height (often after an endplate injury) and bulges out on all sides under compression — like a flat tyre. The third type is an annular tear, where the inner layers of the disc separate and allow the gel nucleus to leak between them — often caused by excessive twisting.
How do I know which type of disc bulge I have?
The pattern of your symptoms gives important clues. If bending forward aggravates your pain, a focused bulge is most likely. If compression (like carrying heavy bags or overhead lifting) is the main trigger rather than bending, reduced disc height is more likely. An annular tear is often associated with a history of significant twisting injury. A thorough physical assessment by a knowledgeable therapist is the most reliable way to distinguish between them.
Is a disc tear the same as a herniated disc?
An annular tear (the third type of disc bulge) is related but not quite the same as a full herniation. In an annular tear, the gel leaks between the inner layers of the annulus but remains contained within the outer wall. In a true herniation, the gel breaks through the outer wall entirely. A tear is generally less severe but still painful and requires careful management — particularly avoiding twisting movements.
Can all types of disc bulge be treated without surgery?
In the majority of cases, yes. Conservative treatment (movement modification, appropriate exercise, load management) is effective for most disc bulge presentations. Surgery is generally only considered when symptoms are severe, persistent, and unresponsive to conservative care — or when there are signs of nerve compression affecting strength or bladder/bowel function.