The morphology of the oropharynx and tongue of the muscovy duck (Cairina moschata).

Abstract

The morphology of the oropharynx and tongue of the muscovy duck was studied with a view to identifying structural features that may infl uence nutrition, food intake and ingestion, as well as to provide a foundation for the recognition of pathology of the bird in this region.The results illustrated that the roof of the oropharyngeal cavity was formed by a cartilaginous hard palate that lacked papillae on its mucosal surface, but exhibited a prominent median longitudinal mucosal fold, the median palatine ridge.Orderly arranged rows of notches, the lamellae, formed the lateral boundaries of both the roof and fl oor of the oropharynx.The tongue, which was located on the fl oor of the oropharyngeal cavity, was characterized by a prominent dorsal median sulcus, numerous lateral brush-like horny lingual papillae and a bell-shaped dorsal surface elevation, that formed the base (caudal ) of the organ.This bell-shaped elevation may be similar to the torus linguae of ruminants.Histologically, the features of the tongue include a non-keratinized stratifi ed squamous epithelial lining on both its dorsal and ventral surfaces, a wide connective tissue layer, containing lingual glands, blood vessels and nerves, and a core of paraglossum and associated striated muscles.In conclusion, the oropharynx and tongue of the muscovy duck exhibits certain anatomical features that are unique to this species, and the morphological modifi cations of this region of the digestive tract may be adaptations to the bird's habitat and mode of feeding.