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 the 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 expensive. Aortic arch malformations are responsible for disorders which cannot be understood without a knowledge of their embryology. The embryonic aortic system is a typical example of Haeckel's law of recapitulation. A human embryo at stage 13 was prepared in 5 mm sagittal sections so as to reconstruct the entire dorsal aorta, the second (transient) arch, the third and fourth arches, and the sixth arches responsible for the pulmonary artery, pharynx, larynx and tracheoesophageal axis. They are only 5 pairs of arches in man. At this stage, the most important vessel is represented by the dorsal aorta with a cerebral route, due to predominance of the development of the central nervous system and its vascularisation over other organs. Vascularisation of the lower limbs 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 understanding of aortic arch malformations.