On the 15th day of intrauterine development, at the extremity of the embrionary disk, a hollow, known as stomodeum, is formed between the cephalic extremity of the neural tube and the umbilical vesicle (1,5).
The stomodeum is separated from the cephalic intestine, or in anterior position by the oro-pharyngian membrane, which is resorbed over a quite short time interval, between week 1 and week 7.