Chapter 11 Flashcards
What are the boundaries of the nasal cavity?
Boundaries are external nares to the choanae
What are the choanae and what is their clinical significance?
Choanae are the passageways between the nasal cavity and the nasal pharynx. Clinical significance is choanal atresia.
What is the false nostril and what is its significance?
The false nostril is the nasal diverticulum, a cutaneous pouch lateral to the nasal cavity. It allows extreme dialation of the nostril (flaring).
How do the paranasal sinuses form and what are their probable functions?
The paranasal sinuses form by invasion of nasal epithelium between the external and internal plates of the skull. Their function may be to give a large head with light weight, protection, or to create resonance for vocalization.
Which species have a palatine sinus and what does it communicate with? What serves as a partial barrier between these two cavities?
Only in ruminants, communicates with the maxillary sinus
-The infraorbital canal separates these two cavities
What is the lacrimal bulla and what is its significance?
The lacrimal bulla if found in ruminants at the caudal end of the maxillary sinus. It is paper thin sheet that acts as a barrier at the end of the maxillary sinus.
What is the prominent external landmark of the equine maxillary sinus?
The facial crest (unique to the horse) forms a prominent external landmark for the equine maxillary sinus.
Compare and contrast the rostral and caudal maxillary sinuses and their communications
- The horse is unique in the fact that the maxillary sinus is divided into caudal and rostral compartments. Pigs and ruminants only have one maxillary sinus.
- The caudal compartment communicates with the frontal sinus via frontal-maxillary opening (unique to the horse).
- The rostral compartment is separated from the caudal compartment by a perpendicular plate (bony septum). It opens into the nasal cavity via a nasomaxillary opening.
In which two species does the frontal sinus cover the entire brain case?
The frontal sinus of the ox and the pig covers the entire brain case.
What is the significance of the equine frontal sinus in removal of the last molar tooth? What is frontal maxillary opening and which species have it.
In the horse, the frontal sinus is the site of a trephine hole (rostral-medial to orbit) where a punch is passed through to reach the last molar tooth.Only the horse has one.
How is the chonchofrontal sinus formed and how is it drained?
The chonchofrontal sinus is formed by an extension of the frontal sinus into the dorsal concha. The frontal sinus is drained by drilling a hole through the dorsal concha with a intramedullary bone pin.
