Anatomical observations in the pharynx of the mouse with special reference to the nasopharyngeal hiatus (Wood Jones).

The mouse pharynx, especially the muscles, was anatomically studied in detail considering the structures of the laryngeal cartilages and the hyoid bone. The nasopharyngeal sphincter was formed by the palatopharyngeus and the levator palati muscles. It was suggested that the former contracted the 'palatopharyngeal eminence' (named by the present authors) and the latter drew up the soft palate, then the nasopharyngeal hiatus was closed. At the rostral end of the esophagus, there existed the 'thyro-pharyngo-esophageus muscle', denominated by the present authors. It was suggested to represent in the area of the esophagopharynx and to compress the tube by any sphincteric functions.