The vascular anatomy of the vestibular labyrinth in man

1. A survey of the literature on the vascular anatomy of the vestibular labyrinth in Man is presented, and the methods of investigation used to visualize the vessels are evaluated. A generally correct picture of the subject is provided by the various studies published since Siebenmann's monograph. There are, however, some conflicting points as well as some lack of data with regard to the course and relationships of the large vessels and the capillary areas of the cristae and maculae. 2. This study presents a systematic description of the vascular anatomy of the vestibular labyrinth in Man, from the main arterial and venous stems to the capillary areas, with particular attention to the relationships between the vessels and the osseous walls, neural, and membranous structures. The vessels were visualized by a composite method including the selective injection of the internal auditory artery with coloured silicone or India ink; the counterstaining of the labyrinth with osmic acid; the cutting of the petrous bone in 1-mm thick, serial sections that were cleared with methylsalicylate. The sections were studied by stereomicroscopy, using mainly reflected light. Photos and drawings were made to illustrate the findings. New names were introduced for vessels hitherto unnamed, and some traditional names were modified in order to give a more precise and descriptive terminology. 3. The description followed the two main arteries, the capillary areas and the three main veins. The vestibular labyrinth is supplied by the superior vestibular artery and by the inferior vestibular artery which is a branch of the vestibulo-cochlear artery. The superior vestibular artery runs along the anterior aspect of the vestibule from the utricular nerve up to the cristae of the superior and lateral canals. It supplies the macula of the utricle, the cristae and ampullar crures of the superior and lateral canals. The inferior vestibular artery runs mainly along the medial wall of the vestibule. It supplies the last tract of the scala media and the vestibular caecum with a peculiar pattern which appears to be an adaptation of the common cochlear arrangement to the different spatial condition. It also supplies the macula of the saccule, the crista and ampullar crus of the posterior canal as well as the simple crures of the three canals. The vascular arrangement of the maculae and cristae has a similar three-layered architecture.(ABSTRACT TRUNCATED AT 400 WORDS)