Definition: a series of arterial channels encircling the embryonic pharynx in the mesenchyme of the pharyngeal arches. There are potentially six pairs, but in mammals the fifth pair is poorly developed or absent. The first and second pairs are functional only in very young embryos; the third pair is involved in the formation of the carotids; the fourth arch on the left is incorporated in the arch of the aorta; the sixth pair forms the proximal part of the pulmonary arteries.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
© Copyright 2018 Wolters Kluwer. All Rights Reserved. Review date: Sep 19, 2016.