Cervical sinus

During Human embryogenesis the mandibular arch and hyoid arch grow more rapidly than those behind them, with the result that the latter become, to a certain extent, telescoped within the former, and a deep depression, the cervical sinus, is formed on either side of the neck.The head and neck of a human embryo thirty-two days old, seen from the ventral surface. During Human embryogenesis the mandibular arch and hyoid arch grow more rapidly than those behind them, with the result that the latter become, to a certain extent, telescoped within the former, and a deep depression, the cervical sinus, is formed on either side of the neck. This sinus is bounded in front by the hyoid arch, and behind by the thoracic wall; it is ultimately obliterated by the fusion of its walls.