Lecture 10 - Nasal Cavities & Paranasal Sinuses Flashcards
What are nasal cavities?
pair of wedge-shaped spaces divided by a septum
How would we describe the floor and apex of the nasal cavity?
wide floor and narrow apex
How are nasal cavities separated from the oral cavity?
by the hard plate
How are nasal cavities separated from the cranial cavity and orbit?
by numerous different bones
What are the 3 regions of the nasal cavity?
- olfactory region
- respiratory region
- nasal vestibules
What is another name for the medial wall of the nose?
the nasal septum
What is the choana?
posterior opening of nasal cavities into nasopharynx
How is the lateral wall of the nose divided?
into 4 air channels by 3 nasal conchae
What does the olfactory region contain?
olfactory receptors
What does the respiratory region contain?
respiratory epithelium
Which region of the nose is the largest?
the respiratory region
What is the area inside the nostrils called?
the nasal vestibule
What is the nasal vestibule lined with?
skin + hair
What does each nasal cavity contain?
3 nasal conchae
What do the 3 nasal conchae create?
4 air channels in between them
What are the 3 nasal conchae called?
superior, middle and inferior
What bone are the superior and middle nasal conchae part of?
the ethmoid bone
What bones is the inferior nasal conchae part of?
separate bones
What is the is found in the nasal mucosa?
respiratory epithelium
What are conchae also known as?
turbinates
What are meatuses?
air channels/recesses separated by nasal conchae
What is the air channel above the superior concha?
sphenoethmoidal meatus
What is the air channel between the superior and middle conchae?
superior meatus
What is the air channel between the middle and inferior conchae?
middle meatus
What is the air channel below the inferior concha?
inferior meatus
What are the 4 meatuses called?
sphenoethmoidal, superior, middle, inferior
How many bones are in the ethmoid?
13
What does the perpendicular plate of the ethmoid bone contribute to?
the nasal septum
What does the conchae of the ethmoid bone contribute to?
the lateral walls of the nasal cavity
What does the cribriform plate of the ethmoid bone contribute to?
the roof of the nasal cavity
What does the orbital plate of the ethmoid bone contribute to?
the orbit
Is the ethmoid bone paired or unpaired?
unpaired
What kind of bone is the vomer bone?
unpaired
What does the vomer contribute to?
the nasal septum
What does the vomer form?
the medial wall of the choanae
What is the medial wall of the nasal cavity called?
the nasal septum
What are the 3 main structures of the nasal septum called?
- septal cartilage
- ethmoid bone
- vomer
Which structures of the nasal septum is soft and mobile?
the septal cartilage
What is the orientation of the ethmoid bone?
perpendicular
What is another name for the ethmoid bone?
perpendicular plate
Which structure of the nasal septum is thin and forms the posteroinferior aspect of it?
vomer
What are the choanae bordered by (3)?
the sphenoid bones, the horizontal plates of palatine bones, and the vome
What are the lateral walls of the nasal cavity characterized by?
alternating conchae and meatuses
What kind of surface do the lateral walls of the nasal cavity have?
irregular and complex surface
What components are found in the lateral walls of the nasal cavity?
bone, cartilage and soft-tissue components
What restrains and directs airflow through the nasal cavities?
conchae
What facilitates warming and humidification of air between the nares and choanae?
large surface area
What are the bones found in the lateral wall of the nasal cavity? (8)
- Frontal bone
- Nasal bone
- Lacrimal bone
- Ethmoid bone (incl. superior & middle conchae)
- Inferior concha
- Maxilla
- Palatine bone (perpendicular plate)
- Sphenoid bone (medial pterygoid plate)
What are the bones found in the superior wall of the nasal cavity? (3)
- Frontal bone
- Ethmoid bone (cribriform plate)
- Sphenoid bone (body)
What are the bones found in the inferior wall of the nasal cavity? (2)
- Maxilla (palatine process)
- Palatine bone (horizontal plate)
What are the bones found in the medial wall of the nasal cavity? (2)
- Ethmoid bone (perpendicular plate)
- Vomer
What provides sensory innervation to the nasal cavity?
branches of the opthalmic nerve (CN V1) + maxillary nerve (CN V2)
What branches of the opthalmic nerve provide sensory innervation to the nasal cavity?
the ethmoidal branches of nasociliary n.
What branches of the maxillary nerve provide sensory innervation to the nasal cavity?
nasal nerves (various branches)
What is the nasal cavity “divided” by?
an oblique line between the posterior sphenoethmoidal recess + apex of nose to show pattern of innervation & blood suppl
What carries the blood supply to the nasal cavity?
branches of ophthalmic artery (A) + maxillary artery (B)
What is found within nasal cavities?
numerous anastomoses
What is one of the arterial anastomoses found in the nasal cavity?
greater palatine artery + sphenopalatine artery
Where does the greater palatine artery + sphenopalatine artery anastomose?
in the incisive canal of maxilla
How many pairs of air sinuses surround the nasal cavity?
4
What do the paranasal sinuses connect to and drain into?
the nasal cavity
What are the paranasal sinuses lined by?
respiratory epithelium
What are the paranasal sinuses innervated by?
branches of CN V
How are the paranasal sinuses named?
for the bones in which they are located
What are the names of the 4 paranasal sinuses?
frontal sinus
sphenoidal sinus
ethmoidal sinus
maxillary sinus
How do the paranasal air sinuses develop?
as pneumatic (air-filled) diverticula from the respiratory part of the nasal cavity
Are the paranasal sinuses absent or present at birth?
absent
When do paranasal sinuses enlarge?
as spaces invade the adjacent bones throughout childhood and early adolescence
What are the 2 reasons why paranasal sinuses are important?
- they have a role in establishing facial architecture
- spread of infection & referred pain
What are the 7 paranasal sinus drainages?
- Ethmoidal infundibulum
- Opening of maxillary sinus
- Opening of nasolacrimal duct
- Opening of posterior ethmoidal air cells
- Opening of sphenoidal sinus
- Ethmoid bulla + openings of middle ethmoidal air cells
- Opening of pharyngotympanic (auditory) tube
Ethmoidal infundibulum
frontal sinus + anterior ethmoidal air cells -> middle meatus via semilunar hiatus
Opening of maxillary sinus
maxillary sinus -> middle meatus via semilunar hiatus
Opening of nasolacrimal duct
lacrimal sac -> inferior meatus
Opening of posterior ethmoidal air cells
posterior ethmoidal air cells -> superior meatus
Opening of sphenoidal sinus
sphenoidal sinus -> sphenoethmoidal recess
Ethmoid bulla + openings of middle ethmoidal air cells
middle ethmoidal air cells -> middle meatus
Opening of pharyngotympanic (auditory) tube
connection between middle ear + nasopharynx
What is the lacrimal apparatus?
system of orbital structures for production and drainage of lacrimal fluid (a.k.a., tears)
What are the 4 components of the lacrimal apparatus?
- Lacrimal gland + excretory ducts
- Lacrimal canaliculi (openings = puncta)
- Lacrimal sac
- Nasolacrimal duct
Where does the nasolacrimal duct drain into?
nasal cavity
What are transsphenoidal hypophysectomies?
surgical approach for removing the pituitary gland (hypophysis) & other tumours in /
near the sella turcica
Why do we perform transsphenoidal hypophysectomies?
- minimally invasive procedure (compared to a craniotomy, for example)
- minimal morbidity and/or complications
- straightforward recovery
