Embryogenesis of the peripheral nervous system.

Embryogenesis is a complex, wide-ranging event. Key processes may proceed simultaneously in different portions of the embryo, or sequentially, with phase offsets as waves of maturation pass outward from an initial point toward the periphery. The molecular signals used to pattern the body commonly serve multiple functions and reiterate as the body plan progresses. This article therefore presents first the anatomic model of the peripheral nervous system, so that the final goal is clear. It then reviews the terminology needed to describe embryogenesis. The article's first section reviews neural development. The main portion of the article addresses the maturation of the fetal nervous system in terms of the evolving gross morphology and the molecular signals that pattern these changes.