Bulging discs and herniated discs sound like similar problems. While they do have some similarities, they also have important differences, including what causes them.
Contrary to popular belief, a bulging disc is not a lighter version of a herniated disc.The main difference between a bulging and herniated disc is where the damage starts.
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What Is a Bulging Disc?
A bulging disc occurs when thenucleus pulposus—the soft, jelly-like center of the disc that gives the disc shock-absorbing capacities—extends beyond its normal position inside the disc structure, but remains contained within the annulus fibrosus.
The annulus fibrosus is the tough outer covering of the disc that keeps the nucleus pulposus contained when it’s healthy and without tears. The annulus is made of fibrous material organized concentrically in a criss-cross pattern.
In an undamaged intervertebral disc, the outer edge (the annulus fibrosus) tends to line up with the edge of the vertebra to which it is attached. However, as the name suggests, bulging discs extend past this boundary.
Migration is the movement of the disc inside the annulus fibrosus. The study looked at how bulges got bigger or smaller depending on the position of the spine.
The amount of disc migration is associated with the degree of degenerative changes present in the spine. Generally, a disc bulge is not more than 3 millimeters (mm).
In general, such changes may or may not causediscogenic pain.
A small bulge in your disc that shows up on an MRI may actually be a normal finding. In other words, a bulging disc may simply be a slight variation in typically described anatomy.
Bulging Disc Causes
Other things that may lead to a bulging disc include:
A bulging disc may be a sign that you’re in the first stage of disc disease.
While bulging discs may cause pain, they don’t always. When a bulging disc does cause pain, it may be because the disc is pressing on the spinal cord or a spinal nerve root.
Symptoms may include:
Disc Bulge: Significance and Treatment
Herniated Disc
Unlike a disc that is bulging, a herniated disc occurs whentearsin or ruptures of the outside of the annulus allow some of the soft material nucleus pulposus to exit the disc.
Pain and other symptoms related to a herniated disc may occur if the escaped nucleus pulposus comes into contact with a spinal nerve root.
Similar to bulging discs, herniated discs are not always symptomatic. Whether they are or not generally depends on whether the leaked disc material makes contact with nerve tissue.
When symptoms do occur, they may be similar to those of a bulging disc, i.e., pain, nerve-related sensations, weakness, and/or numbness that go down one arm or leg.
Herniated discs progress in stages, from prolapsed to protruding, then extruding, and finally sequestration, where the disc material is completely severed from the main disc structure.
Disc Desiccation: Treatment and Support for Aging Bodies
A Word From Verywell
A herniated disc and a bulging disc form differently. A bulging disc starts internally—affecting the inside part of annulus’s fibers—it will likely leave the soft material of the nucleus intact.
A herniated disc occurs when the outside of the annulus fibrosus is torn or somehow compromised, allowing the inner nucleus to leak outside the disc structure.
It is hard to know which one of these you have based on symptoms alone. It’s important to get a diagnosis and treatment to alleviate discomfort and prevent the condition from worsening.
3 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel rothman SL, Sze GK.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.Spine J. 2014;14(11):2525-45. doi:10.1016/j.spinee.2014.04.022Hu JK, Morishita Y, Montgomery SR, et al.Kinematic evaluation of association between disc bulge migration, lumbar segmental mobility, and disc degeneration in the lumbar spine using positional magnetic resonance imaging.Global Spine J. 2011;1(1):43-8. doi:10.1055/s-0031-1296056The Spine Hospital at the Neurological Institute of New York.Herniated disc (cervical, thoracic, lumbar).
3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel rothman SL, Sze GK.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.Spine J. 2014;14(11):2525-45. doi:10.1016/j.spinee.2014.04.022Hu JK, Morishita Y, Montgomery SR, et al.Kinematic evaluation of association between disc bulge migration, lumbar segmental mobility, and disc degeneration in the lumbar spine using positional magnetic resonance imaging.Global Spine J. 2011;1(1):43-8. doi:10.1055/s-0031-1296056The Spine Hospital at the Neurological Institute of New York.Herniated disc (cervical, thoracic, lumbar).
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel rothman SL, Sze GK.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.Spine J. 2014;14(11):2525-45. doi:10.1016/j.spinee.2014.04.022Hu JK, Morishita Y, Montgomery SR, et al.Kinematic evaluation of association between disc bulge migration, lumbar segmental mobility, and disc degeneration in the lumbar spine using positional magnetic resonance imaging.Global Spine J. 2011;1(1):43-8. doi:10.1055/s-0031-1296056The Spine Hospital at the Neurological Institute of New York.Herniated disc (cervical, thoracic, lumbar).
Fardon DF, Williams AL, Dohring EJ, Murtagh FR, Gabriel rothman SL, Sze GK.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.Spine J. 2014;14(11):2525-45. doi:10.1016/j.spinee.2014.04.022
Hu JK, Morishita Y, Montgomery SR, et al.Kinematic evaluation of association between disc bulge migration, lumbar segmental mobility, and disc degeneration in the lumbar spine using positional magnetic resonance imaging.Global Spine J. 2011;1(1):43-8. doi:10.1055/s-0031-1296056
The Spine Hospital at the Neurological Institute of New York.Herniated disc (cervical, thoracic, lumbar).
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