Studies of elastic tissue formation in the developing bovine ligamentum nuchae

Abstract

The fetal ligamentum nuchae showed 2 distinct stages of development, each characterized by its cell population and fiber products. Fibroblasts of the early phase have extensive ergastoplasm apparently associated with collagen production; those of the late phase have an attenuated cytoplasm and coincide with an increase of elastic tissue content. The elastic fiber comprised a core of fine elastin fibrils (100-130 nm diameter) and a surrounding mantle of microfibrillar protein. As development proceeded, the elastin fibrils appeared to coalesce with each other and also with elastin fibrils from adjacent fibers to form composite mature elastic fiber, a process which was accompanied by a loss of microfibrils. A characteristic of elastic fibers from adult ligament, not apparent in the fetal tissue, was that of bifurcation.