Describe the communication between the paranasal sinuses and the nasal cavity in the horse
The dorsal conchal sinus and frontal sinus communicate (this is the conchofrontal sinus). The conchofrontal sinus communicates with the caudal maxillary sinus through the frontomaxillary opening. The sphenopalatine sinus also communicates with the caudal maxillary sinus. The caudal maxillary sinus communicates directly with the nasal cavity via the nasomaxillary opening. The ventral conchal sinus communicates with the rostral maxillary sinus, which communicates directly with the nasal cavity via the nasomaxillary opening but is separated from the caudal maxillary sinus by a bony septum.