The beginning

Rudiment (lat. primordium) - any formation of the organism of the embryonic or intrauterine period of development that develops and remains intact, differing in the specificity of structure and functioning from the final adult organ or part of it. The concept of rudiments emerged especially clearly within the framework of ideas about ontogenesis. The rudiments are ethical when, in the process of development, any structures are formed from the cells of the germ layer, the organizations from which, gradually undergoing morphogenetic transformations, form the so-called final organ or tissue; metaplastic, these are rudiments that, being the rudiments of one and the same whole, independently serve various organs of the growing organism; heterotypic, for example dental tissue. In phyloontogenesis, organogenetic studies are of interest.