RECONSTRUCTION OF THE AORTIC ARCHES OF A 28-DAY HUMAN EMBRYO (STAGE-13) USING THE BORN TECHNIQUE

We present a reconstruction of the aortic arches of a human embryo at stage 13. Only a few original observations have been reported during t he last 110 years and only two with three-dimensional reconstructions. The reconstruction technique originated in 1885. Modern computerized reconstruction techniques have no evident advantages and are more expe nsive. Aortic arch malformations are responsible for disorders which c annot be understood without a knowledge of their embryology. The embry onic aortic system is a typical example of Haeckel's law of recapitula tion. A human embryo at stage 13 was prepared in 5 mm sagittal section s so as to reconstruct the entire dorsal aorta, the second (transient) arch, the third and fourth arches, and the sixth arches responsible f or the pulmonary artery, pharynx, larynx and tracheoesophageal axis. T hey are only 5 pairs of arches in man. At this stage, the most importa nt vessel is represented by the dorsal aorta with a cerebral route, du e to predominance of the development of the central nervous system and its vascularisation over other organs. Vascularisation of the lower l imbs appears before their macroscopic development and is probably one of the factors responsible for their growth. Many such reconstructions are necessary if conclusions are not to be based on too few specimens to be sound. A better knowledge of embryology lead to a new understan ding of aortic arch malformations.