Topography of the Rabbit Paranasal Sinuses As a Prerequisite to Model Human Sinusitis

Background: Anatomical studies of the rabbit paranasal cavities are impelled by the increasing interest in the rabbit model to investigate human sinusitis. Although several such studies have already been performed, the topography of the rabbit dorsal conchal and maxillary sinuses is described ambiguously and the existence of the ethmoidal, frontal and sphenoidal sinuses is controversial.

Methodology: The paranasal cavities were investigated using corrosion casting, gross and histological cross-sectioning, and micro-CT scanning of rabbit noses followed by computerized three-dimensional reconstruction.

Results: Micro-CT scanning was most useful to illustrate the dorsal conchal sinus, the large maxillary sinus consisting of a dorsal and a ventral recess, and the sphenoidal sinus. All these sinuses are paired and symmetrical. A large connection is present between the dorsal conchal sinus and the maxillary sinus resulting in one large conchomaxillary cavity. The sphenoidal sinus lies most caudal and is surrounded by the presphenoid bone. The openings from the nasal cavity into the conchomaxillary cavity and the sphenoidal sinus are very small.

Conclusions: The absence of frontal and ethmoidal sinuses in any of the rabbits examined is a major difference between the rabbit and human sinuses. The rabbit maxillary sinus seems most appropriate for experimental work.