Under a scanning electron microscope, microcirculation of the vestibular organ was observed with the corrosion casting technique. The following results were obtained. The anterior vestibular artery (AVA) was distributed to the utriculus, lateral ampulla, superior ampulla and semicircular canal. The dense capillary network was only found below the hair cells areas. The coiling artery or arteriole was found at the central part of the hair cell areas. The blood vessels of the planum semilunatum formed a loop structure like renal tubules. A secretory or absorptive function of the endolymph was suspected in this portion. One or two arterioles run to the semicircular canal without communicating with the crista ampullaris. The blood vessels of this portion run straightfoward in the canal and never make a dense capillary network.
