A description of the relationship between the nasomaxillary aperture and the paranasal sinus system of horses.

Disease of the paranasal sinuses of the horse is common and treatment often involves lavage and sometimes surgery. The development of minimally-invasive, sinus-specific treatments, such as balloon sinuplasty, requires a thorough understanding of this complex anatomical region. To improve this understanding, 10 heads from dead horses of various ages were grossly dissected. The heads were transected sagittally and each half was dissected to expose the left and right nasomaxillary apertures and associated structures which were then photographed and measured. Entrances from the rostral and caudal maxillary sinuses into the maxillary aperture were found that led to a common exit at the middle nasal meatus. The caudal and rostral maxillary sinuses had their own, completely distinct outlets (entrances into the nasomaxillary aperture). There was no significant effect of side on measured variables.