A scanning electron microscopy study on human otoconia genesis.

The genesis of the otoconia was studied with SEM in several human fetuses. The results of the present paper together with previous reports (1, 2, 13) support the hypothesis that otoconia genesis may develop according the following stages: (1) calcification of some sensory and supporting cells; (2) extrusion of the calcified cellular material and some organic substances in "sponge-like bodies"; (3) deposition of diverse core seeds in these areas giving rise to a random calcium carbonate crystallization and incorporation of matrix organic material; (4) growth of otoconia developing linearly with a gradual change in shape from spherical to ovoid, rhombohedral, and cylindrical forms; (5) inhibition of crystal growth occurring once a critical unsaturated calcium endolymph state and an adequate size of statoconial membranous chambers are reached.