Stomatogenesis

Stomatogenesis refers to the embryonic development of the mouth. This complex process involves the formation of both the oral cavity and the jaws. In vertebrates, stomatogenesis begins with the formation of the stomodeum, an ectodermal invagination that will eventually become the anterior part of the mouth. Adjacent to the stomodeum is the pharyngeal arch system, which plays a crucial role in jaw development.

The stomodeum deepens and is separated from the foregut by a thin membrane called the oral plate or buccopharyngeal membrane. This membrane eventually breaks down, connecting the stomodeum to the pharynx. Simultaneously, the pharyngeal arches undergo significant remodeling. The first pharyngeal arch, known as the mandibular arch, forms the upper and lower jaws. Cartilage precursors within these arches, such as Meckel's cartilage for the lower jaw and palatoquadrate cartilage for the upper jaw, differentiate and give rise to skeletal elements and associated muscles.

Other pharyngeal arches also contribute to the formation of structures within the oral and pharyngeal regions. For instance, the second pharyngeal arch contributes to the hyoid bone and muscles of facial expression. The development of teeth, tongue, salivary glands, and the palate are also integral parts of stomatogenesis, occurring concurrently or sequentially with the formation of the oral cavity and jaws. Disruptions during stomatogenesis can lead to congenital malformations of the face and mouth.