Vascular anatomy of the inner ear of the guinea pig--a sem study of the corrosion cast--

Development and regression of cochlear blood vessels in fetal and newborn mice

Various strains of mice have been used for hearing research, but there have been few reports regarding the cochlear vasculature in mice. In this study, the development of the cochlear vasculature was investigated in C57BL/6 mice from day 15 of gestation to day 15 after birth, and mature vessels were also observed in 3-month-old mice. Both India ink injection and the resin casting method were used. On gestational day 17, spiral vessels of the basilar membrane were developing and were elaborating communicating branches that ran toward the external wall and the spiral lamina. On day 18, the spiral vessels showed the largest diameter of all vessels in the cochlea, but these vessels subsequently regressed and finally disappeared by day 14 after birth. The external wall vessels formed a single-layer capillary network at birth and subsequently divided into two layers, which became the vessels of the stria vascularis and the spiral ligament vessels. This process occurred progressively from the basal turn toward the apical turn between days 5 and 8 after birth. A general tendency for the cochlear vasculature to mature from the basal turn towards the apex was observed.

Venous communications of the cochlea after acute occlusion of the vein of the cochlear aqueduct

The vein of the cochlear aqueduct (VCAQ) is the principal drainage vein of the cochlea in the guinea pig. Morphological observations of the VCAQ and its adjacent structures were made by studying serial sections of the cochlea. We detected the presence of two collateral vessels from the mucoperiosteal veins of the middle ear which communicated with the VCAQ. Following acute occlusion of the VCAQ, marked dilatations of these vessels were observed in corrosion cast preparations. Our findings suggest that these vessels act as collateral veins following acute venous congestion of the inner ear.

The vasculature of the external wall of the gerbil's inner ear

This paper reports the results of a scanning electron microscopy (SEM) study of the vessels in the cochlea of the Mongolian gerbil. Using the microcorrosion technique and SEM we were able to obtain an overall picture of the capillary beds in the cochlea of the gerbil. The vasculature of the inner ear of the gerbil was found to differ from Wistar rats. The different vascular anatomy in comparison with the Wistar rat is discussed.