The structure and blood supply to the Baikal seals organ of hearing

Abstract

The article studies anatomical features of the structure and blood supply to the outer ear, the middle ear and the inner ear of the Baikal seal. The outer ear has no auricle. The long external auditory meatus has a slightly curved shape of various diameters and cartilaginous plates. The bone base of the middle ear is a triangular-shaped tympanic bubble. It has specific features in the topography of openings for the facial nerve and the bony auditory tube. The drum cavity is voluminous, repeats the contour of the tympanic bladder. It contains auditory ossicles (malleus, anvil, lenticular ossicles and stapes). The inner auditory meatus is deep; the entrance to the aqueduct is located medially on the rocky part of the inner ear. The main source of blood supply to the organ of hearing is the occipital (blood supply to the opening area of the bony auditory tube) and caudal ear deep temporal (blood supply to the area of the external auditory canal; they are formed form the external vascular network of tympanic membrane skin) arteries. They are branches of the external carotid artery, as well as the internal auditory (blood supply to the facial nerve and forms the internal vasculature) and rocky (blood supply to the vestibule, semicircular canals and cochlea) branches of the basilar artery.