Medical Terminology for Bulging Discs
The medical term for a bulging disc is "disc bulge" or "bulging disc," which is formally classified as a type of intervertebral disc displacement or disc protrusion. 1
Standard Medical Nomenclature
The accepted medical terminology includes several related terms that describe different disc pathologies:
- Disc bulge: A broad-based extension of disc material beyond the normal disc space margins 1
- Intervertebral disc displacement: The formal medical term encompassing various disc abnormalities 1
- Disc protrusion: A more focal extension of disc material, often used interchangeably with bulging disc in clinical practice 2
- Herniated disc (or disc herniation): Herniation of the nucleus pulposus through the fibrous outer covering (annulus fibrosus), which is distinct from but related to disc bulging 1, 3
Important Clinical Distinctions
Disc bulges and disc protrusions represent similar pathology and do not have significantly different internal architecture based on discographic findings. 2 Both conditions are associated with:
- Stage 2 or 3 annular disruptions in 80-100% of cases 2
- Similar degrees of disc degeneration 2
- Comparable rates of pain reproduction during diagnostic injection 2
The key pathophysiologic relationship is that disc bulging results from extracellular matrix degradation, loss of nucleus pulposus and water content, and subsequent loss of disc height. 4 Histologically, bulging discs may contain transverse, concentric, or radial tears in the annulus fibrosus. 5
Clinical Significance
These disc abnormalities are extremely common in asymptomatic patients and correlate poorly with symptoms. 1 Thoracic disc abnormalities including herniations, bulges, and annular fissures are frequently found in people without mid-back pain. 1 Similarly, lumbar disc protrusion prevalence increases from 29% in 20-year-olds to 43% in 80-year-olds among asymptomatic individuals. 1
The coexistence of bulging and herniation can occur in the same disc, termed "bulging and herniated disc," challenging the traditional view that herniation would not occur in a bulging disc. 5