By Dr. Michael Gofeld, MD PhD — Medical Director, Unika Medical Centre
“It’s your disc.” “It’s arthritis in your facet joints.” “Your SI joint is out.”
Most people living with back pain have been handed a single culprit by a scan report, by a clinician, or by an advertisement promising that one injection or one device will make it go away. It is a tidy story. In most cases, it is wrong.
The spine does not fail one part at a time. It fails as a segment. Understanding that is the difference between chasing a structure and treating a patient.
Where the “one cause” idea comes from
- Imaging names what it sees. MRI is excellent at showing anatomy and poor at showing pain. Reports list findings structure by structure, and the most visible finding quietly becomes “the cause.”
- Single targets are easy to sell. One culprit justifies one procedure. The simpler the story, the easier the treatment is to market.
- Research looked for “pain generators” one at a time. Early studies estimated how often the disc, the facet joint or the sacroiliac joint was responsible — as if each patient had only one.
The spinal segment: one unit, many parts
Spine specialists describe the spine as a stack of functional spinal units — two adjacent vertebrae and everything that connects them:
- The intervertebral disc (the outer annulus and the inner nucleus)
- The two vertebral endplates above and below the disc
- The two facet joints at the back of the segment
- The ligaments — longitudinal ligaments, ligamentum flavum, interspinous and supraspinous ligaments
- The deep segmental muscles, chiefly the multifidus
- The exiting nerve roots, their dorsal root ganglia, and the covering of the spinal canal (dura)
The disc in front and the two facet joints behind form what spine surgeons have long called the three-joint complex. Load one, and you load the other two. Nothing in this unit works or wears in isolation.
Every structure in the segment can produce pain
- Disc. The outer annulus is supplied by the sinuvertebral nerve. In degenerated discs, nerve fibres grow deeper into tissue that is normally pain-insensitive.
- Endplates. The basivertebral nerve supplies the vertebral endplates. Endplate damage and the accompanying bone marrow changes are recognized contributors to back pain.
- Facet joints. The joint capsules are richly supplied by the medial branches of the spinal nerves and respond to stretch and inflammation.
- Ligaments and fascia. The posterior ligaments and the thoracolumbar fascia contain pain-sensing nerve endings.
- Multifidus. These short, deep muscles stabilize each segment, and they are supplied by the same nerve as the facet joint at that level.
- Nerve roots. Roots can be irritated mechanically by narrowing and chemically by inflammatory material released from a damaged disc.
Shared wiring means shared pain
The nerve supply of the segment is not organized as one structure, one wire. It overlaps by design:
- Each facet joint receives nerve supply from two levels, and each medial branch serves two joints.
- The sinuvertebral nerve branches up and down, supplying the disc and posterior ligament across more than one level and across the midline.
- The nerve that carries pain from a facet joint also controls the multifidus at that level. Joint irritation and protective muscle guarding are wired together.
- Signals from the disc, joints and muscles converge on the same nerve cells in the spinal cord. The brain cannot reliably tell them apart.
This is why pain referral patterns from different structures overlap, and why no patient can point to “the” structure that hurts — and no single test on its own can either.
When one part changes, the whole segment changes
Spinal degeneration follows a well-described sequence, often called the degenerative cascade:
- The disc loses water and height.
- The facet joints take on more load; their capsules stretch and their cartilage wears.
- The ligamentum flavum buckles and thickens, and the nerve openings (foramina) narrow.
- The segment passes through a phase of abnormal movement, then stiffens as bone spurs form.
- Throughout, the multifidus is inhibited and wastes, so the segment loses muscular control and the passive structures carry even more load.
Each stage brings a different combination of active contributors. A segment that is predominantly disc-driven at 45 may be dominated by facet joint and foraminal changes at 65. The segment has a history, not a single villain.
Your MRI cannot name the culprit
In people with no back pain at all, imaging findings are the norm, not the exception. A large systematic review found disc degeneration in over a third of pain-free 20-year-olds and in nearly all pain-free 80-year-olds; disc bulges followed the same pattern.
Findings are common. Pain is individual. A scan describes the condition of the segment — not which part of it is driving your symptoms today.
What precise diagnosis actually means
At Unika, diagnosis comes before treatment. That is not a hunt for one culprit. It is a map of the segment — identifying every contributor and establishing which one is dominant now.
- Detailed history and examination — the pattern, mechanical behaviour and neurological findings of your pain.
- Imaging read in context — correlated with your symptoms and examination, never interpreted in isolation.
- Image-guided diagnostic blocks, where indicated — to weigh how much each structure contributes: the dominant driver, not the only one.
- Targeted intervention — directed at the dominant driver or drivers, in the right sequence.
- Specialized spine physiotherapy — to restore segmental muscle control and redistribute load, because no injection restores how a segment moves.
- Neurosurgical assessment — on site, when structural compression or instability requires it.
Treating one structure while ignoring the rest of the segment is how patients end up cycling from one isolated procedure to the next. Treating the segment means treating the whole problem.
Questions to ask about your diagnosis
- Which structures in my segment are likely contributing and which is dominant?
- How do my imaging findings correlate with my examination?
- What is the plan for restoring muscle control and function, not just reducing pain?
- If one treatment helps only partly, what addresses the rest?
The bottom line
Back pain is a segment problem. The disc, endplates, facet joints, ligaments, muscles and nerves share load, share wiring and degenerate together. A diagnosis that names one structure and stops there is incomplete, and so is any treatment built on it.
If your back pain has persisted beyond six weeks, or you have been given a single explanation that does not match how you feel and function, a full spine specialist assessment is the right next step.
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This article is for general education and does not replace an individual medical assessment.