Development of inner ear vessels. A scanning electron microscopic study.

The development of the inner ear vessels of guinea pigs were studied by SEM. Employing 32- to 55-gestational-day-old guinea pig embryos, corrosion casts of inner ear blood vessels were prepared using Mercox resin and then observed by scanning electron microscopy. Between the 35th and 40th gestational days, the vascular structure of the vestibule was sufficiently developed, but the capillary network in the wall of the cochlea remained immature. Thus, in the guinea pig, the development of the vestibular structure precedes the development of the cochlear vessels. Moreover, at both sites, the density of the embryonic blood vessels was high, and the vessels were believed to transport a large blood flow. From about the 40th day of gestation, the coiled vessels and the capillary network in the lateral wall of the cochlea underwent rapid development, and the vascular structure in both the vestibule and cochlea was nearly complete by the time of birth.