Development of the facial region
The structures for the face stem from various primordia around the stomodeum that have arisen up to the tearing of the oropharyngeal membrane (stage 11, ca. 29 days):
- a medial sacculation in front of the oropharyngeal membrane as the primordium of the adenohypophysis.
- the medial frontonasal process (processus frontonasalis) that soon forms a medial and a lateral nasal process on both sides and pushes the adenohypophysis into the stomodeum.
- the bilateral mandibular arch (first pharyngeal arch) with a maxillary and a mandibular process.