Nasal Cavity and Nasopharynx (ENT 2) Flashcards
What forms the bridge of the nose?
Frontal bones articulating with nasal bones
What closes the lateral part of the nasal cavity?
Frontal process of maxilla
What is most of the nose made from?
Cartilaginous skeleton
Where is the septal cartilage?
Through midline of nose
What does the septal cartilage do?
Split nasal cavity into two halves
Where are the lateral cartilages?
Articulate with nasal bones and septal cartilage
Where are the alar cartilages?
Articulate with septal cartilage below
When does the cartilage in the nose stop growing?
Grows throughout life
What forms the superior boundary of the nasal cavity?
Frontal bone
Nasal bone
What contributes to the lateral aspect of the external part of the nasal cavity?
Frontal process of maxilla
What forms the hard palate?
Horizontal plate of maxilla
Horizontal plate of palatine bone
What does the hard palate divide?
Nasal from oral cavity
What forms most of the roof and superior and lateral parts of the nasal cavity?
Ethmoid bone
How does the ethmoid bone project in the nasal cavity?
Laterally in both halves
What does the ethmoid bone do in the midline of the nasal cavity?
Perpendicular plate projects down
What forms the medial aspect of the nasal cavity?
Frontal bone
Nasal bone
Part of ethmoid bone, in particular perpendicular plate
What forms the posterior aspect of the nasal cavity?
Sphenoid bone
How does the septal cartilage close off the nasal septa?
Articulates with perpendicular plate of maxilla and vomer
In which bone is the cribriform plate?
Ethmoid bone
What is special about the cribriform plate?
Has little holes in it
Where is the cribriform plate?
Anterior in midline
What is the crista gali?
Superior process of ethmoid bone located anteriorly in midline, projecting up into anterior cranial fossa
Which bone can a bad break of the nose impact?
Ethmoid bone
What can a fracture of the ethmoid bone mean?
Especially around cribriform plate: damage meninges in anterior cranial fossa Introduce pathway for - Infection - Bleeding into meninges Rhinorrhoea
What is rhinorrhoea?
Leakage of CSF out of subarachnoid space and into nose
What overlies the septum?
Flat sheet of mucosa
What type of mucosa lines the nasal cavity?
Mostly highly vascular mucous mmbrane
Vestibule lined with skin and hair
What is the hair in the vestibule important for?
Trap foreign particles
Where do nosebleeds often come from?
Damage to mucosa
What is the cell type of the mucosa of the nasal cavity?
Ciliated pseudostratified columnar
What is the role of the cilia in the mucosa?
Beat actively towards the front to move mucus from lower airways up and out
How much area does the respiratory area cover?
2/3 of nasal cavity
What covers the lateral wall?
Highly vascular mucosa
In which wall are the turbinates?
Lateral
What are the turbinates?
Bony processes which hang off wall like shelves
What are the turbinates called?
Conchae
- Superior
- Middle
- Inferior
What is located deep to the conchae?
Openings
What is the function of the conchae?
Allow air to bounce in cavity to allow it to get to temperature and humidity close to body’s
Which meatuses are related to the conchae?
Superior, middle, and inferior meatus related to respective conchae
What are the openings behind the conchae mostly for?
Paranasal sinuses
What are the paranasal sinuses?
Spaces in bone
How many paranasal sinuses are there?
Four groups
Where is the frontal sinus?
In frontal bone
Where are the ethmoid sinuses?
In lateral plate of ethmoid bone
Where is the sphenoid sinus?
Posteriorly in sphenoid bone
Where is the maxillary sinus?
Laterally in maxilla
Where do the frontal, ethmoid, and sphenoid sinuses sit in relation to the nasal cavity?
Superiorly
Why are infections more common in the maxillary sinus compared to the other sinuses?
Bacteria find it relatively difficult to migrate to the superior sinuses
How do you naturally drain an infection from the maxillary sinus?
Opening high up in medial wall
Have to stand on head
How can dentists damage the maxillary sinus?
Close to upper molars
If dentist fractures thin plate, can introduce route of infection into sinus
What is the sensory innervation for the frontal, ethmoid, and sphenoid sinuses?
CN V1
Where is pain referred to from the frontal, ethmoid, and sphenoid sinuses?
Skin of forehead
What is the sensory innervation for the maxillary sinus?
CN V2
Where is pain referred to from the maxillary sinus?
Skin of cheeks
Which meatus does the frontal sinus open into?
Middle meatus at anterior end of hiatus semilunaris
What is the hiatus semilunaris?
Crescent shaped groove in middle meatus
Which meatus does the maxillary sinus open into?
Middle meatus at posterior end of hiatus semilunaris
Which meatus do the middle ethmoid sinuses open into?
Middle meatus
Which meatus do the posterior ethmoid sinuses open into?
Superior meatus
Where does the sphenoid sinus open into?
Back of roof of nasal cavity just behind superior concha
Where does the nasolacrimal duct open into?
Inferior meatus
What does the nasolacrimal duct communicate between?
Lacrimal sac on medial aspect of orbit to nasal cavity
Why do you get a runny nose when you cry?
Excess tears run into nasolacrimal duct and spill into inferior meatus
How is the nasal cavity divided in terms of blood supply?
Lateral and medial walls each divided into quadrants
What is the blood supply of the posterior quadrant of the medial and lateral walls?
Sphenopalatine artery
What is the sphenopalatine artery a branch of?
External carotid artery
What is the blood supply of the superior quadrant of the medial and lateral walls?
Ethmoidal arteries
What is the blood supply of the inferior quadrant of the medial and lateral walls?
Greater palatine artery
How does the greater palatine artery enter the nasal cavity?
Through hole in hard palate
What is the blood supply of the anterior quadrant of the lateral wall?
Branches of facial artery
What is the blood supply of the anterior quadrant of the medial wall?
Labial arteries
What is the innervation of the superior half of the nasal cavity?
Branches of CN V1
What is the innervation of the inferior half of the nasal cavity?
Branches of CN V2
What is the nasopharynx?
Part of pharynx behind nasal cavity
Where does the pharynx start and end?
Start: base of skull
End: Lower border of cricoid cartilage at C6
What forms the pharynx posteriorly?
Sling of muscle that closes off back of pharynx
What are the muscles closing the pharynx posteriorly?
Constrictor muscles
- Superior
- Middle
- Inferior
What are the attachments of the constrictor muscles?
On lateral surface of oral cavity, and larynx
In which direction do the constrictor muscles project?
Posteriorly
Where do the constrictor muscles meet?
In midline
What joins the constrictor muscles in the midline?
Median raphe
Where does the superior constrictor attach?
Oral cavity
What does the superior constrictor do?
Close off most of naso- and oropharyx
Where does the middle constrictor attach?
Hyoid bone
What does the middle constrictor do?
Close off some of oro- and laryngopharynx
Where does the inferior constrictor attach?
Thyroid and cricoid cartilage
What does the inferior constrictor do?
Close off laryngopharynx
What closes off some of the spaces between the constrictor muscles?
Fascia deep to muscle
What is the roof of the nasopharynx?
Sphenoid bone
What is the floor of the nasopharynx?
Largely soft palate
What is the posterior boundary of the nasopharynx?
Superior constrictor
Between what do the two spaces in the nasopharynx communicate?
From nasal cavity to nasopharynx
From naso- to oropharynx
Where does the auditory tube open?
In lateral wall of nasopharynx
What does the auditory tube communicate betwee?
Tympanic membrane of auditory canal and nasopharynx
What is the auditory tube important for?
Equalising pressure on either side of tympanic membrane
What happens when mucus blocks or pushes into the auditory tube?
Prevents equalisation
Where are the adenoid/pharyngeal tonsils?
In roof of nasopharynx
What happens when the adenoid tonsils become chronically inflamed?
Obstruct breathing
What does an obstruction in the nasal cavity and paranasal sinuses do to your voice?
Resonance chambers, so changes quality of voice
What is the salpingopharyngeus muscle associated with?
Soft palate
Where does the salpingopharyngeus muscle attach?
Cartilaginous auditory tube
Pharynx
What does the salpingopharyngeus muscle do?
Pulls on opening into nasopharynx
Allows equalisation of middle ear