Morphological and Morphometric Variations of the Tympanic Bulla Between Domestic Shorthair and Brachycephalic Cats Utilizing Computed Tomography

Abstract

Tympanic morphology of the dogs was reported to be varied due to the characteristics of the skull types. The small tympanic bulla is normally seen in brachycephalic dogs. However, this variation in narrowed-skull shaped cats has not been unveiled yet. The objective of this study was to describe the tympanic morphology of cats between brachycephalic and domestic shorthair (DSH) cats. Computer tomography (CT)-skull images of 15 domestic shorthair cats and 11 brachycephalic cats were evaluated for tympanic dimension on transverse and dorsal planes and the tympanic bone thickness. All parameters were compared between both groups. The results revealed that all tympanic parameters measured from the transverse and dorsal CT images were comparable between groups (P > 0.05) except the tympanic bone thicknesses. The result showed that the tympanic bone thickness of the brachycephalic cats was significantly thicker than that of the DSH cats (0.13 ± 0.02 vs 0.10 ± 0.01 cm, P = 0.0005). In conclusion, the present study provides information on CT tympanic morphology between the brachycephalic and DSH cats. Contrast this to the dog's information, skull type was not an effect on tympanic bullae dimension but played a major role on the tympanic bone thickness. This information could be useful during the interpretation of the tympanic bullae related lesion on the CT images.