Computed Tomographic Anatomy of the Trachea, Bronchi and Lungs in the Caspian Pond Turtle (Mauremys caspica)

Objective- The intention of this research is studying the full topographic characteristics of the lower respiratory tract consist of lungs, bronchi, and trachea in Caspian pond tortoise, especially those features that are applicable in clinical examination, and their proximity to other organs.Design- Experimental study.Animals- Six female adult Caspian Pont turtles (Mauremys Caspica)Procedures- Siemens Somatom spirit Dual Slice CT scan machine has been used. The samples were fixed in ventral recumbency to take CT-scan images. In each sample, the CT-scan was done in both fixed limb and neck and extended form. Some morphometric parameters like the volume of the coelomic cavity, right and left lungs, and others were measured through the Syngo MMWP VE40A software.Results- Trachea passing a short distance in the midline of the neck, and deviated to the left; then, it entered to the coelomic cavity. The tracheal bifurcation site was movable and move to caudal parts with neck flexion. The entrance site of the bronchi to the lungs was fixed. With the consideration of coelomic cavity volume and various parts of that in the neck extended position, the lungs consist of 42.12% of the coelomic cavity and 22.58% in the flexed neck position.Conclusion and Clinical Relevance- According to the observations, we can say the flexion of the neck leads to some alterations in the tracheal bifurcation site and locating posteriorly to the lungs hilum. As a result, the way of the bronchus changes to inter the lungs. The branches of bronchus in these turtles also are like other reptiles, and it's not similar to a bronchial tree and it contains just limited small branches. The CT-scan is applicable for alive animals, so this is one of the best choices for anatomical studies in animals who are in danger of extinction.