Macewen sign
Macewen sign
Macewen sign
ALL of the following exhibits Macewen sign EXCEPT?
A. Hydrocephalus
B. Brain abscesses
C. Raised intracranial tension
D. Meningitis
McEwan’s sign in alcohol intoxication is suggestive of –
A. B12 Deficiency related neurological sign
B. Associated Head injury
C. Alcoholic coma
D. Hepatic Encephalopathy
‘Cracked pot sound’ on percussing the skull is seen in –
A. Meningitis
B. Hydrocephalus
C. Cerebral Palsy
D. Cerebellar infarct
Macewen Sign – also called the “cracked pot sign” – is a clinical percussion sign seen in conditions where intracranial pressure or fluid accumulation causes separation of cranial sutures.
1. What is the Macewen sign primarily used to detect?
Macewen sign is elicited by percussion over the skull; a cracked-pot sound suggests hydrocephalus or raised intracranial pressure in infants.
2. In which age group is the Macewen sign most commonly elicited?
It is primarily used in infants and young children before the cranial sutures have fully fused.
3. What physical finding characterizes a positive Macewen sign?
A positive sign produces a cracked-pot sound when percussing the skull, indicating increased intracranial pressure or separation of sutures.
4. Which clinical condition is most often associated with a positive Macewen sign?
Hydrocephalus leads to separation of cranial sutures, allowing the cracked-pot resonance to be elicited.
5. The Macewen sign is best elicited by percussing over which part of the skull?
The sign is typically assessed at the junction where the three skull bones meet, near the anterior fontanelle in infants.
6. Which diagnostic tool has largely replaced the Macewen sign in modern practice?
While Macewen sign can still be used clinically, neuroimaging provides definitive diagnosis for intracranial pathology.
7. The “cracked-pot” sound in Macewen sign occurs due to:
The sound results from vibration over separated sutures with increased fluid pressure beneath.
8. Which historical context saw common use of Macewen sign?
Before CT and MRI were available, bedside signs like Macewen sign were vital for diagnosing hydrocephalus.
9. A positive Macewen sign in an infant warrants which next step?
Confirming the diagnosis with imaging is essential before deciding on surgical or medical intervention.
10. Who first described the Macewen sign?
Sir William Macewen, a Scottish surgeon, described this clinical sign in the late 19th century.
11. Macewen sign is absent when:
Once sutures are fully fused, resonance is lost, and the sign cannot be elicited.
12. Which skull feature is most relevant to eliciting the Macewen sign?
The sign relies on the resonance created by fluid pressure separating cranial sutures.
13. Macewen sign is an example of which type of clinical sign?
It is a percussion sign, as it is elicited by tapping on the skull.
14. In hydrocephalus, which mechanism causes a positive Macewen sign?
CSF buildup leads to ventricular enlargement and separation of cranial sutures.
15. Which other condition, apart from hydrocephalus, can rarely cause Macewen sign?
A large brain abscess causing mass effect can sometimes produce this sign.
16. Which instrument is used to elicit Macewen sign?
The sign is elicited by tapping the skull lightly with fingers.
17. In what type of hydrocephalus is Macewen sign more likely?
Communicating hydrocephalus in infants causes generalized ventricular enlargement, producing the sign.
18. Why is Macewen sign not reliable in older children?
Fusion of sutures prevents the cracked-pot resonance from being elicited.
19. The “cracked-pot” resonance is acoustically similar to tapping on:
The sound is reminiscent of tapping an empty clay pot — hence the name.
20. Which field of medicine historically emphasized Macewen sign?
It was historically important in pediatric neurosurgery and neurology before modern imaging.
Key Details
| Feature | Description |
|---|---|
| Definition | A hollow, resonant, “cracked pot” sound heard on percussing the skull. |
| Cause | Separation of cranial sutures due to increased intracranial pressure or hydrocephalus. |
| Mechanism | The widened sutures allow vibration of the skull bones, producing a characteristic note. |
| Common in | Infants (because sutures are not fused), hydrocephalus, brain abscess, or space-occupying lesions. |
| Elicitation | Percussion of the skull (usually over the frontal or parietal bones) with a fingertip. |
| Clinical relevance | Suggests raised intracranial pressure and warrants urgent evaluation. |
💡 Mnemonic:
“Macewen = ‘Mac cracked pot’” → Think of a hollow pot sound when tapped.
1. Macewen sign is also known as:
The Macewen sign is called the “cracked pot sign” because percussion over the skull produces a sound resembling that of a cracked pot.
2. Macewen sign is most often elicited in:
Hydrocephalus causes separation of cranial sutures in infants, producing the resonant percussion note characteristic of Macewen sign.
3. Which age group is Macewen sign most relevant for?
The sign is primarily seen in infants due to unfused cranial sutures, which can separate under raised intracranial pressure.
4. The sound in Macewen sign is best described as:
The sound is hollow and resonant, similar to tapping on a cracked pot, due to fluid and suture separation.
5. Which pathology other than hydrocephalus can produce Macewen sign?
Space-occupying lesions like brain abscess can cause increased intracranial pressure, leading to a positive Macewen sign.
6. Macewen sign is primarily used to detect which condition?
Macewen sign, also known as the “cracked pot” sound, is a clinical indicator of hydrocephalus or brain abscess, especially in infants with open fontanelles.
7. The “cracked pot” sound in Macewen sign is heard during:
The sign is elicited by percussion over the skull, producing a resonant, cracked pot-like sound.
8. Macewen sign is most reliable in which age group?
It is most useful in infants because their cranial sutures and fontanelles are still open.
9. The pathophysiological basis of Macewen sign is:
Increased intracranial pressure causes suture separation, altering resonance and producing the characteristic percussion note.
10. Macewen sign can be positive in:
It is seen in conditions like brain abscess, where localized pressure leads to suture separation.
| Macewen sign- Question | Answer |
|---|---|
| What is Macewen sign also called? | “Cracked pot” sign |
| Who described Macewen sign? | Sir William Macewen |
| What causes Macewen sign in children? | Separation of cranial sutures due to raised intracranial pressure |
| What condition is it most commonly associated with in infants? | Hydrocephalus |
| How is Macewen sign elicited? | Percussion of the skull over junction of frontal, parietal, and temporal bones |
| What sound is heard in a positive Macewen sign? | Resonant “cracked pot” sound |
| In which age group is it most commonly elicitable? | Infants and young children |
| Why does the sign disappear as the child grows? | Cranial sutures close and ossify |
| Can Macewen sign be found in adults? | Rarely, only with conditions like large skull defects |
| Is Macewen sign specific for hydrocephalus? | No, it indicates increased intracranial pressure from various causes |
| Which imaging is preferred to confirm hydrocephalus? | MRI or CT scan |
| Is Macewen sign present in acute head injury? | Usually absent unless sutures are separated |
| What is the underlying pathology? | Increased intracranial volume causing skull expansion |
| Which bones form the area of percussion? | Frontal, parietal, and squamous temporal bones |
| How is the patient positioned for testing? | Sitting upright |
| What is the clinical significance in infants? | Early indicator of intracranial pathology before fontanelle bulges |
| What other sign may be present with Macewen sign in infants? | Bulging anterior fontanelle |
| What surgical treatment may be required in hydrocephalus? | Ventriculoperitoneal (VP) shunt |
| Is it a reliable sign after cranial sutures close? | No |
| What is the prognosis if underlying cause is treated early? | Usually good |
| No. | Macewen sign |
|---|---|
| 1 | Macewen sign is also known as the “cracked pot” sign. |
| 2 | It was first described by Sir William Macewen. |
| 3 | Elicited by percussion of the skull at the junction of frontal, parietal, and squamous temporal bones. |
| 4 | A positive sign produces a resonant, cracked-pot-like sound. |
| 5 | Commonly seen in infants and young children. |
| 6 | Caused by separation of cranial sutures due to raised intracranial pressure. |
| 7 | Most often associated with hydrocephalus in infants. |
| 8 | May also be seen in other causes of increased intracranial pressure. |
| 9 | Rarely present in adults unless there is a large cranial defect. |
| 10 | Disappears when cranial sutures close and ossify. |
| 11 | Positive sign often accompanies bulging anterior fontanelle. |
| 12 | Can be an early clinical clue before fontanelle bulging is visible. |
| 13 | Imaging such as CT or MRI is needed for confirmation of hydrocephalus. |
| 14 | In acute head injury, the sign is usually absent unless sutures are separated. |
| 15 | The underlying pathology involves increased intracranial volume and pressure. |
| 16 | Patient is usually examined in a sitting position for best sound conduction. |
| 17 | Important in clinical evaluation of infants with suspected intracranial pathology. |
| 18 | Not specific to hydrocephalus—can occur in other intracranial space-occupying lesions. |
| 19 | Surgical intervention, such as ventriculoperitoneal (VP) shunt, may be required. |
| 20 | Early diagnosis and treatment generally lead to a good prognosis. |
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