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Murphy's sign

Murphy's sign 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 Murphy's sign rather than just read about it. In short: In medicine, Murphy's sign (also known as Sweeney’s sign) is a maneuver during a physical examination as part of the abdominal examination. It is useful for differentiating pain in the right upper quadrant.

Key takeaways

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

Reference excerpt

In medicine, Murphy's sign (also known as Sweeney’s sign) is a maneuver during a physical examination as part of the abdominal examination. It is useful for differentiating pain in the right upper quadrant. Typically, it is positive in cholecystitis, but negative in choledocholithiasis, pyelonephritis, and ascending cholangitis.

During physical examination Classically, Murphy's sign is tested for during an abdominal examination in supine position; it is performed by asking the patient to breathe out and then gently placing the hand below the costal margin on the right side at the mid-clavicular line (the approximate location of the gallbladder). The patient is then instructed to breathe in. Normally, during inspiration, the abdominal contents are pushed downward as the diaphragm moves down (and lungs expand). If the patient stops breathing in (as the gallbladder is tender and, in moving downward, comes in contact with the examiner's fingers) and winces with a "catch" in breath, the test is considered positive. In order for the test to be considered negative, the same maneuver must not elicit pain when performed on the left side.

Predictive value Murphy's sign has a high sensitivity and negative predictive value, although the specificity is not high. However, in the elderly the sensitivity is markedly lower; a negative Murphy's sign in an elderly person is not useful for ruling out cholecystitis if other tests and the clinical history suggest the diagnosis.

History The sign is named after American physician John Benjamin Murphy (1857–1916), a Chicago surgeon from the 1880s to the early 1900s, who first described the hypersensitivity to deep palpation in the subcostal area when a patient with gallbladder disease takes a deep breath.

See also Courvoisier's law – when the gallbladder is palpable, painless jaundice is unlikely to be related to gallstones. Murphy's triad

References

External links "Cholecystitis acute". Medcyclopaedia. GE. Archived from the original on 2012-02-05.

Worked examples

Example 1 — a first encounter with Murphy's sign

Start with the simplest possible case. Write down what Murphy's sign 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 Murphy's sign 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 Murphy's sign 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 Murphy's sign

In research
Murphy's sign 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 Murphy's sign 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
Murphy's sign is common in secondary-school and first-year university syllabi. It links to neighbouring topics Diagnostic surgery, Hepatology, Medical signs, so understanding it makes those chapters shorter.
In everyday life
Look for Murphy's sign 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 Murphy's sign in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Murphy's sign means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Murphy's sign out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Murphy's sign in simple terms?

In medicine, Murphy's sign (also known as Sweeney’s sign) is a maneuver during a physical examination as part of the abdominal examination. It is useful for differentiating pain in the right upper quadrant.

Why does Murphy's sign 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 Murphy's sign?

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 Murphy's sign.

Tags

  • Diagnostic surgery
  • Hepatology
  • Medical signs

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