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This arch divides into a maxillary process and a mandibular process, giving rise to structures including the bones of the lower two-thirds of the face and the jaw. The maxillary process becomes the maxilla (or upper jaw, although there are large differences among animals [11]), and palate while the mandibular process becomes the mandible or lower jaw.
The first and second arches disappear early. A remnant of the 1st arch forms part of the maxillary artery, [3] a branch of the external carotid artery. The ventral end of the second develops into the ascending pharyngeal artery, and its dorsal end gives origin to the stapedial artery, [3] a vessel which typically atrophies in humans [4] [5] but persists in some mammals.
The palatopharyngeal arch (pharyngopalatine arch, posterior pillar of fauces) is larger and projects further toward the middle line than the palatoglossal arch; it runs downward, lateralward, and backward to the side of the pharynx, and is formed by the projection of the palatopharyngeal muscle, covered by mucous membrane.
Pattern of the pharyngeal arches. I-IV pharyngeal arches, 1–4 pharyngeal pouches (inside) and/or pharyngeal grooves (outside) a Tuberculum laterale b Tuberculum impar c Foramen cecum d Ductus thyreoglossus e Sinus cervicalis. The pharyngeal apparatus is an embryological structure. [1] [2] It consists of: pharyngeal grooves (from ectoderm)
Continuous with the dorsal end of the first pharyngeal arch, and growing forward from its cephalic border, is a triangular process, the maxillary prominence (or maxillary process), the ventral extremity of which is separated from the mandibular arch by a ">"-shaped notch.
The anterior pillar is the palatoglossal arch formed of the palatoglossus muscle. The posterior pillar is the palatopharyngeal arch formed of the palatopharyngeus muscle . Between these two arches on the lateral walls of the oropharynx is the tonsillar fossa which is the location of the palatine tonsil . [ 3 ]
It appears as a midline swelling from the first pharyngeal arch late in the fourth week of embryogenesis. [1] In the fifth week, a pair of lateral lingual swellings (or distal tongue buds) develop above and in line with the median tongue bud. These swellings grow downwards towards each other, quickly overgrowing the median tongue bud. [1]
The cervical sinus is a structure formed during embryonic development. It is a deep depression found on each side of the neck. It is formed as the second pharyngeal arch (hyoid arch) grows faster than the other pharyngeal arches, so they become covered. The first pharyngeal arch (mandibular arch) also grows slightly faster.