Pyloric Sphincter Size
The pyloric sphincter is typically much smaller than a banana. The pylorus is described as a region at least 3 cm long, with a lumen roughly 1 cm in diameter. [1]
Expected Dimensions
- Typical pyloric diameter thresholds used in infants for ultrasound evaluation are in the millimeter range (for example, pyloric muscle thickness <2 mm and pyloric diameter <6 mm are listed as normal criteria in an ultrasound manual). [2]
- Adult anatomical and physiologic descriptions place the pyloric region length at least 3 cm and lumen diameter around 1 cm. [1]
Comparison With a Banana
A banana’s order-of-magnitude size (several tens of centimeters in length and a few centimeters in diameter) exceeds the typical measured pyloric region length and the typical pyloric lumen diameter. [1]
When Large Size Is Relevant Clinically
Substantially enlarged pyloric measurements are associated with pyloric stenosis in infants, with diagnostic criteria based on measurements of muscle wall thickness, canal length, and pyloric diameter rather than gross “banana-sized” dimensions. [2]