On the sectioned heads many structures can be identified. Starting at the nasal cavity the turbinates (conchae) and nasal meatuses can be appreciated. Also observe the paranasal sinuses. In the horse, the maxillary sinus is divided into rostral and caudal compartments by a bony shelf and they have a shared opening into the middle nasal meatus. The frontal sinus of the horse is commonly referred to as the conchofrontal sinus due to the open communication between both the dorsal conchal and frontal sinuses. In the ox, the maxillary sinus remains undivided, but the frontal sinus is divided into rostral and caudal frontal sinuses. Unlike the horse, where all of the paranasal sinuses either directly or indirectly communicate with the maxillary sinus and through this connection the middle nasal meatus, the paranasal sinuses of ruminate open into either the middle nasal or ethmodial meatuses.
As you move caudally into the nasopharynx the boundaries of this region can be seen, rostrally the paired chonaea and caudally the intrapharyngeal ostium. Two additional openings can be observed in the nasopharynx and these are the openings of the auditory tubes. Generally these can be found in the dorsolateral area of the region. In the pig, a pharyngeal diverticulum is also a characteristic of the nasopharynx and found dorsal to the palatopharyngeal arch.
The oropharynx starts at the palatoglossal arches and ends at the base of the epiglottis. The palatoglossal arches can be difficult to appreciate in some specimens, but it is a band of tissue extending from the palate to the tongue. In the ox and in a lot of the goats, a small opening can be observed in the dorsolateral area of the oropharynx. This is the ostium of the sinus of the palatine tonsil. Do not confuse this with opening of the auditory tube in the nasopharynx (look at your location before answering questions on the exam).
The laryngopharynx extends from the base of the epiglottis to the cricoid cartilage of the larynx.
Identify the cartilages that make up the larynx. These include the epiglottis, thyroid, and cricoid cartilages and the paired arytenoids. The vestibular fold is absent in the ruminant, but present in the other species. In the dog, pig and horse an opening into the lateral laryngeal ventricle can be observed between the vestibular and vocal folds. At the base of the epiglottis the median laryngeal ventricle can be observed in the pig, sheep and horse.
For additional information of the guttural pouch please use the link provided in webct.