If this fusion does not occur properly, an orofacial cleft may develop in the newborn.
This fusion with the medial nasal process will form the inter-maxillary process and result in the eventual formation of the philtrum of the upper lip. The maxillary processes will also grow and meet the lateral nasal processes and extend midline to meet the medial nasal processes. The lower jaw will be formed early as a result of the two mandibular processes. Simultaneously, the maxillary processes from the mandibular branch of the 1st pharyngeal arch will develop and surround the oral cavity. The fifth week, the nasal placodes will be surrounded by the lateral and medial nasal swellings on the frontonasal process. These are precursors to the olfactory epithelium.
The nasal placodes are two ectodermal thickenings that appear at the end of the fourth week on the frontonasal processes. The maxillary processes will later form to a pair of palatal processes.
The 1st arch will give rise two mandibular processes and two maxillary processes (proximal part of the arch). The tissues of the 1st (mandibular) pharyngeal arch originates from mesoderm and the neural crest.
0 kommentar(er)
