Diffuse Disc Bulge

Published: June 9, 2017
Last reviewed: June 15, 2017

This article explains the term diffuse disc bulge commonly found on the reports of magnetic resonance (MR) and computed tomography (CT) images of the spine.

What is the spinal disc?

The spinal or intervertebral discs are cartilages between the bones (vertebra) in the spine (Picture 1).

Spinal or intervertebral disc

Picture 1. A normal spinal or intervertebral disc

What is a disc bulge?

A disc bulge is a condition in which at least 25% (90°) of the disc’s circumference extends beyond its normal limits and the soft disc center does not break out through the outer fibrous ring (Picture 2[1].

Disc bulge - CT image

Picture 2. A CT image of a disc bulge (blue) (source: Radiopaedia, CC license)

What is a diffuse disc bulge?

The term diffuse disc bulge has no specific meaning but just describes a disc bulge in general. However, some doctors may use it instead of a broad-based herniation.

A disc bulge rarely causes any symptoms while a disc herniation can put pressure on the spinal nerve roots and cause pain in the neck, back, arm or leg. If your magnetic resonance (MR) or computed tomography (CT) image report mentions a diffuse disc bulge and it is not clear what it means, ask your doctor.

Details about the causes, symptoms, treatment and prevention of a bulging and herniated disc.

What is a diffuse annular bulge?

A diffuse annular disc bulge is just a long term for a disc bulge but some doctors use it when they want to emphasize that only the outer part of the disc called annulus fibrosus is involved in the bulge and there is no herniation.

What is a minimal or mild diffuse disc bulge?

In a minimal or mild disc bulge, the disc extends only slightly beyond its normal limits and rarely causes any problems.

What is a circumferential diffuse disc bulge?

A circumferential diffuse disc bulge extends over 50-100% of the disc’s circumference [1]. Note, that the severity of the symptoms tends to decrease with the percent of the disc’s circumference involved.

What is a posterior and posterolateral diffuse disc bulge?

A posterior or central diffuse disc bulge points backward to the spinal cord [1].

A posterolateral diffuse disc bulge points backward and laterally to the right or left spinal nerve root and may cause pain in an arm or leg.

What does the diffuse disc bulge L4-L5 or L5-S1 mean?

  • The disc L4-L5 is the one between the 4th and 5th lumbar vertebra in the lower back.
  • The disc L5-S1 is the one between the 5th lumbar and 1st sacral vertebra in the lower back.

If one of these discs bulges out, it may, rarely, cause pain in the lower back, buttock or leg.


  • References

      1. Fardon DF et al, 2014, Lumbar disc nomenclature: version 2.0: Recommendations of the combined task forces of the North American Spine Society, the American Society of Spine Radiology and the American Society of Neuroradiology  The Spine Journal

Leave a Reply

Your email address will not be published. Required fields are marked *