Gross Anatomy and Arterial Vascularization of the Tympanic Cavity and Osseous Labyrinth in Mid-Gestational Bovine Fetuses

This study aims to determine morphological features of certain aural formations, varietal characteristics, and arterial supply in fetal development period in cattle. For this purpose, ears of 10 bovine fetuses in mid-gestation were evaluated. Organ morphology and vascularization in prenatal life were investigated by using corrosion cast technique. It was observed that some aspects of osseous formation and vascular organization in middle and inner ears were not developed completely in the first half of gestation; in addition, cochlea did not its snail-like structure yet, lateral semicircular canal was rather low compared to others and auditory ossicles did not take its final shape. The feeding blood vessels of inner ear were found to demonstrate three different distribution patterns, whereas feeding pattern in middle ear was very similar in many specimens. The presence of stapedial artery was also identified. Differences and similarities with other some species were assessed in terms of both general morphological structure and vascular organization. From this regard, it is thought that this study will constitute a comparative model for both humans and other species and provide morphological contributions since there is not sufficient literature on species-specific ear morphology in the field of veterinary anatomy in contrast to the abundance of studies on humans. Anat Rec, 293:2083-2093, 2010. (C) 2010 Wiley-Liss, Inc.