The sinonasal communication in the horse: examinations using computerized three-dimensional reformatted renderings of computed-tomography datasets

Abstract

BackgroundSinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads.ResultsThree-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P <0.05) between the right and left side of the head.ConclusionsUnder physiologic conditions both paranasal sinus systems are connected to the nasal cavity by equine specific sinonasal channels. To resolve sinus disease it is aimed to maintain or even reconstruct the normal anatomy of the sinonasal communication by surgical intervention. Therefore, the presented 3D analyses may provide a useful basis.

An anatomical study of the dorsal and ventral nasal conchal bullae in normal horses: Computed tomographic anatomical and morphometric findings

“…Computed tomography (CT) permits much more accurate imaging of the complex equine sinonasal region [3,4,9,12,13]. In a companion study we examined the gross anatomical and histological features of these nasal bullae in normal horses.…”

Anatomical and histological study of the dorsal and ventral nasal conchal bullae in normal horses

“…Both nasal conchae are continued rostrally by mucosal folds, which in the case of the ventral concha contains a thick venous plexus (Hare 1975). While the term ‘ventral conchal bulla’ is commonly used to describe the soft bony lamella extending from the dorsal aspect of the maxillary septum (Getty and Hillman 1975, Perkins and others 2009a, b, Finnegan and others 2011), based on Nomina Anatomica Veterinaria (International Committee On Veterinary Gross Anatomical Nomenclature 2012), this structure is more accurately termed the bulla of the septum sinuum maxillarium (maxillary septal bulla) (Brinkschulte and others 2014, Dixon and others 2015).…”

The use of radiography for diagnosis of apical infection of equine cheek teeth

“…The anatomical relationship of the caudal maxillary cheek teeth (08–11s) to the paranasal sinuses is age dependent, with the cheek teeth drifting rostrally with increasing age, meaning the nasomaxillary aperture (sinus drainage angle) is level with the 09/10 interdental space in animals younger than 15 years, whereas it is adjacent to the 10/11 interdental space in animals older than 15 years (Brinkschulte et al . ).…”