Developmental Aspects of the Human Endolymphatic Sac

Abstract

While the two sensory portions of the inner ear, the cochlea and the vestibular system, present a constant anatomy and a regular and uniform development, the third portion, the endolymphatic sac, is highly variable. This also applies to the development of the sac, since the sensory portion of the inner ear has reached its maximum size by mid-term, while the sac continues to grow throughout the entire gestational period (1).

While considerable effort has been directed toward the developmental aspects on the cochlea and the vestibular system, relatively few reports have been published on the development of the endolymphatic sac. the general developmental aspects have however been well covered by Watzke &Bast, Anson et al. and Anson (1, 2, 3). Thus the development of the vestibular aqueduct in humans, as in other animals, has been described in great detail. This also applies to the size and shape of the epithelial lining of the sac as well as its general orientation in the temporal bone (4). the fine-structural aspects of the saccus epithelium on the high resolution light microscopical and electronmicroscopical levels have however not previously been described in the human endolymphatic sac. the present report is a short summary of a forthcoming paper (5).