Differences in the anatomy of the lower respiratory tract in selected species of the order Testudines

Abstract

The lower airways of turtles consist of the larynx, trachea and bronchi. Due to incomplete information about the anatomical structure of the lower respiratory tract in turtles, we decided to explore this topic more deeply. The material for this study included 95 turtle cadavers. Terrestrial tortoises were represented by 63 individuals from 8 species, aquatic and semi-aquatic turtles by 32 individuals from 11 species. The sex ratio was 54 females to 41 males. In addition to the anatomical autopsies and assessments of the macroscopic structures, numerous measurements were performed. The length, width and height of the larynx and trachea, and the length of the bronchi were measured. We found clinical significance in two parameters. The first one is the formation of the rima glottidis, which is significantly shorter and narrower in the aquatic turtles than in the terrestrial tortoises. It follows that for these species, we should use a smaller diameter of endotracheal cannula for intubation. The second parameter is a very short trachea in tortoises of the genus Testudo. The length of the trachea is only a few centimetres, which significantly increases the risk of intubation into one bronchus only.