Origin of distention
Examples from the Web for distention
Distention of the seminal vesicles with a superabundance of seminal fluid also acts as a source of irritation.Plain Facts for Old and Young|John Harvey Kellogg
The larv are hatched in the abdomen of the female, which is capable of distention.Directions for Collecting and Preserving Insects|C. V. Riley
The other is by the contraction and distention of the midriff or diaphragm.The Young Priest's Keepsake|Michael Phelan
Hence the uncomfortable sense of distention, because the stomach walls do not contract readily for the expulsion of food.
This seems to be due to the distention of the stomach, either by gas or by liquid.
Word Origin and History for distention
also distension, early 15c., from Middle French distension and directly from Latin distensionem (nominative distensio, distentio), noun of action from past participle stem of distendere (see distend).