On the etiology of congenital malformation of the meniscus.

In order to explain the occurrence of malformed meniscus in man, dissections were carried out in various vertebrates; they revealed that menisci shaped like a plate, disc, or ring are physiological components of the knee joint in several vertebrates. Microscopic examinations of tissue sections through the knee joint of human embryos revealed that the meniscus develops from an intermediate mesodermal blastema, which has the shape of a thick plate in the early embryonic period. The occurrence of a malformed meniscus in man may be explained by persistence of a very early embryonic stage and also possibly by reversal to a phylogenetic shape.