ABSTRACT
The External Nose: Frontonasal Process The ectodermal nasal placodes (Figure la) sink dorsally into the frontonasal mesenchyme, each forming a nasal fovea or pit (Figure lb), in the roof of which an oronasal sulcus is entrained. The sulcus separates medial from lateral nasal process, as in the shark (Figure lb). The maxillary process grows over the sulcus and fuses with the medial nasal process (6 weeks), completing an ante rior nasal aperture (Figure 2). The lateral nasal process forms the anterior naris, or nostril.
