Illustrated Review of the Embryology and Development of the Facial Region, Part 1: Early Face and Lateral Nasal Cavities

Anterior oblique drawing of a 5-week embryo (A) shows the further growth of the medial and lateral nasal processes and the development of the nasal sac. The bucconasal groove is shown. B, Anterior oblique drawing of a 6-week embryo shows closure of bucconasal groove completing the floor of the nasal cavity and progressive flattening of the nasal sac openings, mainly as a result of ventrolateral growth of the medial nasal processes. The nasal sacs are also pushed toward the midline as the maxillary processes grow. Anterior oblique drawing of a 7-week embryo (C) and a 10-week (D) embryo shows the progressive medial movement of the nasal sacs and the resulting progressive pushing upwards of the frontonasal process.