The development of Meissner corpuscles in primate digital skin.

Digital skin from fetal and neonatal primates was examined using light and electron microscopic techniques to document the development of the Meissner corpuscle. Generation of the receptor was initiated early in the third trimester by fine neurites which left the superficial dermal nerve plexus, ascended the dermal papillae and entered the basal epidermis. As maturation of the Meissner corpuscle continued, the axons were confined to the apex of the dermal papilla, where they were oriented parallel to the surface to the surface of the skin and terminated among cytoplasmic extensions of presumptive lamellar cells. During late fetal life the complexity of the lamellar cell stacking increased and the lamellar cell bodies were found solely at the base of the receptor. Numerous axon terminals were evident between the cytoplasmic lamellae. The appearance of the neonatal Meissner corpuscle was indistinguishable from that of the adult, indicating that the complete cycle of development is concluded before birth.