- The outer shell is called the annulus fibrosus. It is composed of tough, fibrous cartilage that binds the vertebrae together but is flexible enough to allow movement.
- The nucleus pulposus is the innermost part of the disc, composed of softer cartilage. It serves as a shock absorber to support the body’s weight and to maintain the structural integrity of the spinal column.
Bulging Discs are Degenerative; Herniated Discs are Trauma-Related
There is often some confusion as to the difference between a bulging disc and a herniated or ruptured disc and the likely cause of each. A bulging disc extends beyond the space it normally occupies, much like a hamburger patty that is too big for its bun. Typically, the part of the disc that bulges is the tough outer shell, the annulus fibrosus. Bulging discs are most commonly associated with the normal aging process; and as such they are considered symptomatic of a degenerative process or pathology. Bulging discs are relatively common, especially among the aging population. They usually—but not always—cause no pain.
By contrast, herniated discs result when a crack in the annulus fibrosus allows some of the soft inner cartilage, the nucleus pulposus, to protrude outside the disc. Herniated discs are also known as ruptured or slipped disc. While a bulging disc represents a degenerative pathology, herniated discs are associated with a traumatic force—a violent burst of energy as may occur in a fall or car accident.
Pattern of Tear is Telltale Marker: Circumferential versus Radial
The telltale marker distinguishing a bulging disc from one that is herniated is the type of tear manifesting in the annulus fibrosus. Any kind of tear in the annulus fibrosus can alter disc shape, but in determining causation, the pattern of tear indicates whether it is symptomatic of disc pathology or related to trauma, either current or pre-existing. This can be determined through an MRI or discogram or by examining how the disc reacts in the presence of the tear.
At the most basic level, bulging discs will show a circumferential tear through the annulus fibrosus; radial tears are caused by trauma, either current or pre-existing. Studies have shown that circumferential tears are produced by chronic forces—stress and strain over a prolonged period of time, causing the layers of the annulus fibrosus to separate. Radial tears are caused by a single burst of energy—as happens in a fall or car accident—when the innermost nucleus pulposus is incapable of absorbing the shock.
Fazzalari and Manthey investigated the etiology of different types of annulus tears. They concluded that there was no correlation between radiating tears and other types of annulus disease or pathology. In other words, concentric tears and radiating tears are caused by totally independent processes. Furthermore, they found that theories proposing that concentric tears could tear or coalesce into radial tears was invalid and could not be substantiated by their results.
Consult with a Top Trial Attorney with Experience in Representing Spinal Injuries
When dealing with spinal disc pain, it is important to understand the cause or source of the pain. Insurance companies are all too happy to categorize spinal disc problems as degenerative in nature or pre-existing, especially if the injured disc presents in conjunction with other arthritic or degenerative changes. If you have a spinal disc injury caused by the negligent or purposeful actions of another, choose a trial attorney with experience in handling spinal injury cases, one who understands the important correlation between disc presentation and causation. For a free legal consultation to discuss your legal options, call: 314-409-7060 or 855-40-CRASH (toll free).