Facet Joint Pain or Disc Pain? Two Back Problems That Behave in Opposite Ways

Two people describe low back pain in almost identical words. One of them dreads a long drive. The other one dreads standing at a counter. That single difference points at two different structures.

Here is what each structure is, how the two patterns separate in practice, and why a scan often adds less than people expect.

The only synovial joints in the spine

Facet joints, also called zygapophyseal joints, sit in pairs at the back of every spinal level. The StatPearls review of lumbosacral facet syndrome describes them as paired diarthrodial joints and the only synovial joints of the spine. Each one has hyaline cartilage over subchondral bone, a synovial membrane, and a capsule that holds roughly 1 to 2 mL.

That construction matters, because it means these joints can behave like other synovial joints in the body. They can become arthritic, they can stiffen after a period of rest, and they can be irritable in the morning and loosen through the day. Degenerative osteoarthritis is the most common cause of facet pain, and prevalence goes up with age.

The nerve supply has a detail worth knowing. Each facet joint is supplied twice, by the medial branch of the posterior ramus at its own level and by the branch one level above. The L3-L4 joint, for example, is supplied by both the L2 and L3 medial branches. That dual supply is the reason an injection aimed at a facet joint has to target two nerves rather than one, and it is part of why the pain is often hard to localise precisely.

Why the disc hurts at all

Healthy discs have very little nerve supply, which is one reason disc pain took so long to be understood. The StatPearls review of lumbosacral discogenic syndrome describes the sinuvertebral nerve as supplying the posterior annulus, the back part of the outer ring of the disc, along with the posterior longitudinal ligament. In healthy discs, that neural penetration reaches about 3 mm into the outer three layers of the annulus.

So the outer edge of the disc has sensation and the middle does not. Pain from a disc generally comes from that outer region and the tissues around it. This is also why disc pain and nerve root pain are separate things: the disc itself can hurt without any nerve root being compressed. If you have leg symptoms travelling below the knee with numbness, weakness, or shooting pain, that is a different conversation, and our article on sciatica and referred pain covers where that line sits.

The mirror-image pattern

This is the part that does most of the work in a clinical assessment.

The facet pattern, as described in the StatPearls facet review, is localised low back pain, often worse in the morning and after a period of inactivity. It may refer into the buttock, groin, or thigh, and the referral ends above the knee. There is no neurological deficit. Extension and rotation, meaning bending backward and twisting, aggravate it.

The discogenic pattern runs the other way. The StatPearls discogenic review describes pain that is midline or paraspinal, sometimes radiating to the flanks or buttocks, typically worse with axial loading, sitting, or bending forward, and relieved by bending backward or lying flat on the back.

Put simply: one group of people wants to stand up, the other group wants to sit down.

That is a useful starting point rather than a diagnosis. Real backs are mixed. Someone can have irritable facet joints and a degenerated disc at the same level at the same time, and a long flare can blur the pattern until the acute irritation settles. Our guide to the first 72 hours of a low back flare covers what to do while the picture is still unclear.

Why the physical tests are not the answer

Both reviews are direct about the limits of physical examination.

For facet pain, facet loading, which means extension combined with rotation in standing, provokes pain but is described as unreliable for diagnosis. It tells you the movement hurts, which you already knew. A negative straight-leg raise is genuinely helpful in a different way, because it helps rule out nerve root involvement rather than ruling in the facet joint.

For discogenic pain, the review states plainly that there are no specific physical tests that diagnose it.

That leaves the diagnostic procedures. Medial branch blocks are described as the only accurate means of confirming the facet joint as the source of pain, with greater than 80 percent relief considered definitive. Because single blocks carry a 30 to 45 percent false-positive rate, two blocks on separate occasions are the standard approach. For the disc, provocative discography is the fluoroscopically guided procedure used.

Most people with low back pain never need either of these. They are reserved for cases where a specific procedure is being planned and the source needs to be certain.

The scan problem

This is the number that changes how people think about their imaging report.

The StatPearls discogenic review reports that degenerative disc prevalence in people with no symptoms at all rises from 37 percent at age 20 to 96 percent at age 80, with the sharpest increases happening through age 50. Read that again with your own age in mind. A large share of people walking around pain-free have discs that look degenerated on a scan.

That does not make imaging useless. It means a finding on a scan has to be matched against what the pain actually does before anyone can call it the cause. A degenerated L4-L5 disc in someone whose pain is worse in extension and eases with sitting is probably not the whole story. Our article on when an MRI is actually needed for low back pain goes through the situations where imaging changes the plan.

What treatment looks like for each

Conservative care comes first for both.

For facet pain, the StatPearls review describes physiotherapy involving lumbosacral stretching and strengthening along with core strengthening, plus heat, ice, and myofascial release. When conservative care is not enough, radiofrequency ablation of the medial branches is described as giving relief for six months to one year, and intra-articular corticosteroid injection is described as giving short to intermediate relief.

For discogenic pain, conservative management centres on physiotherapy and home exercise. The review discusses the McKenzie method with directional preference assessment, which means finding the direction of movement that reduces or centralises your symptoms and building the programme around it. For many people with a discogenic pattern that direction is extension, though the assessment exists precisely because it is not the same for everyone.

The overlap between the two programmes is larger than the differences. Both need graded loading, both need trunk strength that holds up under real-life demands, and both do badly with long periods of rest. Rebuilding capacity to lift again matters in both cases, and our guide to returning to lifting after back pain covers how that progression is structured.

When to get it looked at

Low back pain that has lasted more than a few weeks, that keeps returning in the same pattern, or that is limiting your work or training is worth having assessed properly. The assessment is mostly about the pattern: what makes it worse, what makes it better, where it goes, and whether anything neurological is happening.

Some symptoms need urgent medical attention rather than a physiotherapy booking. Changes in bladder or bowel control, numbness in the saddle area between the legs, or progressive weakness in the legs can indicate cauda equina compression, which is a medical emergency. Go to the emergency department at Lions Gate Hospital or call 911. Fever with back pain, unexplained weight loss, or pain following significant trauma also need a physician rather than a wait-and-see approach.

If your back pain has a clear pattern and nobody has tested it yet, book an assessment and we will work out which positions load what. You can see what we treat or reach the clinic here.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Sources

• Lumbosacral Facet Syndrome, StatPearls, NCBI Bookshelf
• Lumbosacral Discogenic Syndrome, StatPearls, NCBI Bookshelf
• College of Health and Care Professionals of BC public registry

This article is for general information only and does not constitute medical advice, diagnosis, or treatment. Individual presentations vary, and assessment findings and treatment plans differ from person to person. If you are experiencing severe symptoms, neurological changes (numbness, weakness, bowel or bladder changes), or a significant trauma, contact your physician or emergency services. Care at Medstar Sport Physio & Health is provided by practitioners registered with their respective British Columbia regulatory colleges.