Craniofacial development external
Week 4 - growth of ectomesenchyme cells leads to development of nasal placodes in the frontonasal processes
Week 5 - nasal placodes invaginate backwards and medially to form nasal pits
Week 5.5 and 6 - Medial sides of nasal pits fuse forming primary nasal septum and intermaxillary process
Week 7 - Primary palate is also formed from the intermaxillary process
Week 8 - Maxillary processes fuse with the lateral and medial nasal processes and the mandible