science

Posterior ramus syndrome

Posterior ramus syndrome is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Posterior ramus syndrome rather than just read about it. In short: Posterior ramus syndrome, also referred to as thoracolumbar junction syndrome, Maigne syndrome and dorsal ramus syndrome is caused by the unexplained activation of the primary division of a posterior ramus of a spinal nerve (dorsal ramus of spinal nerve). This nerve irritation causes referred pain in a well described tri-branched pattern.

Key takeaways

Posterior ramus syndrome belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Posterior ramus syndrome to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Posterior ramus syndrome from memory before moving on to harder problems.

Reference excerpt

Posterior ramus syndrome, also referred to as thoracolumbar junction syndrome, Maigne syndrome and dorsal ramus syndrome is caused by the unexplained activation of the primary division of a posterior ramus of a spinal nerve (dorsal ramus of spinal nerve). This nerve irritation causes referred pain in a well described tri-branched pattern. The diagnosis is made clinically with the variable presence of four criteria. Descriptions of clinical involvement of posterior rami were found as early as 1893, but not until 1980 that LDRS was so precisely described. While any (or all) of the three branches may present themselves, their constancy of location is what allows this to be defined as a distinct syndrome. One branch sets off anteriorly to the groin or pubic region. A second branch remains posterior, innervating the lower back and upper gluteal region. Thirdly a lateral take-off passed down the anterolateral thigh or trochanter region. The term sclerotome, distinct from dermatome for anterior rami involvement, has been proposed to describe the pattern of pain produced from posterior rami.

Diagnosis The affected posterior ramus ends cutaneously causing trophic changes of the skin referred to as cellulalgia. Neuropathic pain is found in three well described regions and serves as the principal clinical component in diagnosing Lumbar Dorsal Ramus Syndrome (LDRS). Typical neuropathic skin changes are present: a thickening or nodularity of the skin, hair loss or even a swollen puffy appearance. Patients with pain in any of these three regions should have a complete physical exam of the entire spinal column including palpation of the facets and spinous processes in hopes of determining the level of origin. Secondly the patient will not usually have spontaneous pain at the offending spinal level. Pain can be provoked by palpation of the facet joints, or the level can remain veiled, with only the referred pain as evidence of the defect. Usually unilateral, bilateral cases have been described as we present here. Patients will not have pain radiating below the knee, which is more typical of anterior ramus involvement. Third, radiographic evidence is non-contributory. MRI, CT and myelography are all ineffective at localizing the at-fault level. The typical degenerative changes seen on most images may lead to unnecessary surgery or false diagnosis. The posterior ramus is far removed from herniating or bulging discs. The fourth criterion clinches the diagnosis: pain relieved by injection of local anesthetic into the correct facet joint. This diagnostic procedure can also be therapeutic; the injection of steroids or radiofrequency denervation of the medial branch can be added for refractory cases. Essential to remember is that the pattern of referred pain in no way hints at the spinal level involved. Multiple studies confirm that there is considerable overlap in the distribution of pain stemming from the zygapophyseal joints, including anterior, lateral or posterior thigh, groin, lumbar spine region, and trochanter region. This overlap of innervation is poorly handled by the standard dermatome map which physicians rely on to trace pain back to its source.

Further reading Scott-Charlton, W.and Roebuck, D.J. The Significance of Posterior Primary Divisions of Spinal Nerves in Pain Syndrome. The Medical Journal of Australia. 1972; 2:945–948. Maigne, R. Low back pain of thoracolumbar origin (T11-T12-L1). In: Maigne, R., Second Edition: Diagnosis and Treatment of Pain of Vertebral Origin. Taylor and Francis Group, 2006:289–98. McCall IW, Park WH, O’Brien JP. Induced pain referral from posterior lumbar elements in normal subjects. Spine 1979;4441–6. Marks R. Distribution of pain provoked from lumbar facet joints and related structures during diagnostic spinal infiltration. Pain 1989;39:37–40. Fukui, S. Distribution of Referred Pain from the Lumbar Zygapophyseal Joints and Dorsal Rami. The Clinical Journal of Pain 1997:13;303–307. Sherrington, C.S., Experiments in Examination of the Peripheral Distribution of the Fibres of the Posterior roots of some Spinal Nerves. Philosophical Transactions of the Royal Society of London, vol. clxxxiv. 1893. Maigne, R. Low Back Pain of Thoracolumbar Origin. Archives of Physical Medicine and Rehabilitation. 1980:61;389–395. Scott-Charlton, W.and Roebuck, D.J. The Significance of Posterior Primary Divisions of Spinal Nerves in Pain Syndrome. The Medical Journal of Australia. 1972; 2:945–948.

Illustrations

Worked examples

Example 1 — a first encounter with Posterior ramus syndrome

Start with the simplest possible case. Write down what Posterior ramus syndrome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Posterior ramus syndrome before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Posterior ramus syndrome ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Posterior ramus syndrome

In research: Posterior ramus syndrome appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Posterior ramus syndrome in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Posterior ramus syndrome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Syndromes affecting the nervous system, so understanding it makes those chapters shorter.
In everyday life: Look for Posterior ramus syndrome outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Posterior ramus syndrome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Posterior ramus syndrome means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Posterior ramus syndrome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Posterior ramus syndrome in simple terms?

Why does Posterior ramus syndrome matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Posterior ramus syndrome?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Posterior ramus syndrome.