- Frontal process
- Medial and lateral nasal processes
- Mandibular arch I
- Maxillary process
- Epithelial parts of oral cavity rostral to palatoglossal arch are ectodermal (palatine tonsil)
- Elongation of mandibular arch and maxillary process results in the elongation of oral cavity
- Bilateral nasal pits bounded by lateral nasal process and medial nasal process.
- Deepening of pits form the nasal cavity which is initially separated from the oral cavity
by the oronasal membrane. This membrane ruptures causing the confluence of nasal cavity with oral cavity.
- Division of Nasal Cavity into Two Halves: The medial nasal prominences merge which
results in a nasal septum separating two nasal cavities. Prominences also form vomer bone upon which nasal septum rests.
- Rostrally, medial nasal septum fuses with maxillary process and thus forms incisive bone
- Lateral Nasal Process fuses with Maxillary Prominence. During fusion a line of ectoderm persists which later grows and canalizes and thus forms a nasolacrimal duct - medial canthus to nasal cavity
- Palatine processes of the maxilla grow medially and caudally to form hard palate and soft palate
- Branchial groove-1: Auricle, ext acoustic meatus.