Pitfall normal pylorus

Clinical information

A three month old child was presented as an emergency case at the children's department.
For a longer period this child vomits after each meal. Clinical not dehydrated.
CAVE: ( Infantile) Hypertrophic Pyloric Stenosis or ( I) HPS.

Brief description

Examination in right sided position.
The correct measurement for HPS may vary from article to article.
It is helpful to remenber the first digits of the number pi 3,1415.
- single muscle layer > 3mm
- pyloric transverse diameter > 14 mm
- longitudinal measurement > 15 mm
In this case there was an incorrect measurement what led to a misinterpretation for HPS.
Secondly there was no clear antral nipple sign, this refers to pyloric mucosa protruding into the gastric antrum.
Several minutes later a second look revealed passage of gastric content through the pylorus, distending the antropyloric region.
Now a correct measurement of the single muscle layer amounted to 1,3 mm and a normal longitudinal measurement of 11 mm

Ultrasound Images & Clips


Dynamic evaluation is crucial, as a normal passage of gastric content which distends the antropyloric region excludes HPS.


  • Sex: Male
  • Body part: stomach