Some observations on the development of the human hyoid bone.

Investigations on the human hyoid bone in several developmental stages reveal that with the chondrification of the mesenchymal blastema a typical interzone between the body and the greater cornua is formed. This disc of closely packed blastemal cells, distinct and broad in the earlier stages, is reduced in thickness in the course of further development. In fetuses between 5 and 6 months old and in newborns the formation of joint cavities can be seen in some cases. In other cases, however, a small transverse line of cells persists between the two cartilaginous elements. These findings are interpreted as different developmental stages of a diarthrosis generally formed between the corpus and the cornu majus. The fact that in the adult the lesser horn is connected directly to the cornu majus and not to the body is confirmed by the embryological investigations reported in this study.