Nasal Cavity & Paranasal Sinuses Flashcards Preview

Block 2 > Nasal Cavity & Paranasal Sinuses > Flashcards

Flashcards in Nasal Cavity & Paranasal Sinuses Deck (25)
Loading flashcards...
1
Q

Describe the relationship between the upper respiratory tract and GI tract.

A

They share a common proximal pathway:

  • Nasal cavity superior to the oral cavity (divided by hard palate bone)
  • Oesophagus being posterior to the trachea
  • > why you can feed a nasogastric tube through the nasal cavity + into the stomach
2
Q

Describe the structure of the upper respiratory tract.

A

Nasal cavity includes 2 nares divided by the septum -> posterior part of nasal cavity is choanae (entrance to nasopharynx) -> nasopharynx -> oropharynx (posterior of oral cavity) -> laryngopharynx (posterior to larynx)

3
Q

What is the nasal cavity?

A

Wedge shaped region between the orbits that extends from nares to choanae

4
Q

What are the names of the 3 bony shelves in the nasal cavity and the spaces underneath them (from top down)? What is the epithelium covering them and their vascular?

A
  1. Superior concha (part of ethmoid bone)
    Superior meatus
  2. Middle concha (part of ethmoid bone)
    Middle meatus
  3. Inferior concha (own bone)
    Inferior meatus
    All covered in mucus epithelium + very vascular
5
Q

In what direction to the concha project?

A

Inferomedially from lateral wall on both sides relate to the nasal septum

6
Q

What are the functions of the nasal cavity? What are the main characteristic features that allow it to do this?

A

Warms, humidifies + filters incoming air because there is highly vascular mucosal tissue covering the bony concha projections + concha also create turbulent air flow via curled projections

Amplifies sound + produces resonance in our voice too

Polyps, infection + congestion in the nasal cavity will therefore disrupt these functions (e.g. inferior meatus polyp or congested mucosa)

7
Q

What are the 3 mucosa lined regions of the nasal cavity (in order of the furthest to outside world and innermost structure)? What are their functions?

A
  1. Nasal vestibule region: hair bearing skin (stratified squamous epithelium) - filtering + abrasion resistance
  2. Olfactory region: olfactory lining + nerve endings - smell + interpretation of smell
  3. Respiratory region: pseudostratified columnar ciliated epithelium + mucus producing goblet cells
8
Q

What is the nasal septum composed of? What effects can a deviated septum have?

A

Bones + cartilage (allows nose to be flexible)

Nasal cavity functions will be disrupted e.g. warmth, air flow, filtering + voice resonance

9
Q

The inferior portion of the nasal cavity called the __ makes up the superior part of the hard palate of the oral cavity.

A

Vomer

10
Q

What would be the name of a defected hard palate? What are the effects of this?

A

Cleft palate

Communication between entire nasal cavity + oral cavity

11
Q

What is the main role of the concha? What would you see if you looked up a patients nasal cavity at first glance?

A

Increase surface area
The inferior concha would be the first structure you would see as its the biggest, the nasal septum would be in the middle + the middle concha will be more posterior and superior

12
Q

Describe the bloody supply to the nasal cavity.

A

High vascular + anastomotic

Multiple vessels anastomose on the anterior nasal septum = little areas/Kiesselbach plexus (vessels aren’t hard to damage so can bleed if nose is picked too much)

Arteries + veins present so flow of bleed will change i.e. slow bleed if from vein + vice versa

13
Q

What is the sensory innervation of the nasal cavity?

A

Trigeminal (CN V) nerve has 3 divisions: Va, Vb + Vc

Olfactory (CN I) nerve endings go through cribriform plate in ethmoid bone inferior to the cranial cavity

14
Q

What are the 3 divisions of the trigeminal nerve? How does this explain pain referral of the face?

A

Va = Opthalmic (pain referral to/from frontal head)

Vb = Maxillary (pain referral to/from maxillary teeth)

Cv = Mandibular (pain referral to/from jaw/temples)

15
Q

If someone has sustained facial trauma that has fracture their cribriform plate, what can happen? Why?

A

Protrusion of the cribriform plate up into the cranial cavity will cause the patient to experience CSF rhinorrhoea + anosmia as it will hit the meningeal coverings separated by CSF + the olfactory nerve endings

16
Q

Why is the nasal cavity not isolated where it sits? What structure is near it + what problems can arise here?

A

The lacrimal sac in the corner of the eye drains into the nasolacrimal duct which opens into the inferior meatus

  • Blocked duct (e.g. cold/congestion) -> epiphora as cannot drain quick enough
  • Mechanical obstruction/blockage at any point along structure (e.g. polyp, eyelash, trauma) -> dacrostenosis
  • Inflammation (due to blockage) -> dacryocystitis
17
Q

What are the 4 air-filled cavities within nasal cavity i.e. paranasal air sinuses?

A
  1. Frontal
  2. Ethmoid
  3. Maxillary
  4. Sphenoid
    (named after bones of skull they are found in - can use orbitals as landmarks to find them in X-ray)
18
Q

What type of epithelium lines the paranasal air sinuses? Why do they need to drain and where do they drain into?

A

They are lined with respiratory epithelium that produces mucus due to goblet cells so must drain into nasal cavity where you will either blow it out of your nose or swallow it

19
Q

Where/how do the paranasal sinuses drain? What’s special about maxillary drainage?

A

Frontal (x2), ethmoid + maxillary: middle meatus
Sphenoid: above superior concha

Maxillary sinus drains in a superior + posterior direction in the nasal cavity - only sinus that does not drain with gravity (why laying down when you have a cold is helpful for congestion)

20
Q

What is the structure of the maxillary sinus? What is in close relation to it? How would poor drainage affect it?

A

Base, floor, reef, apex (pointing to zygoma) + lateral wall = huge structure (can be seen as huge dark circles on CT scan anterior of head)

Close relation to maxillary nerve therefore, may feel pain in the sinus if you have maxillary tooth pain

Septa can affect drainage -> infection, inflammation, sinusitis (mucosa can become inflamed by 3cm massively impeding drainage)

21
Q

What is the sphenoid sinus drainage? What is it close too? Explain why this is important.

A

Drains into sphenoethmoidal recess right above superior concha next to the bony crevesce + cranial cavity

Important as you can access part of the brain through this sinus in a less invasive but direct way e.g. in pituitary gland surgery

22
Q

Where does the frontal sinus drain?

A

Via the frontonasal duct into the middle meatus

23
Q

What is in the ethmoid sinus and what seperates it from the orbits? Explain why this is important.

A

Multitude of tiny spaces and ethmoid air cells - different to other sinuses

Separated from orbits by only a thin plate of bone so infection can spread here causing peri-orbital cellulitis

24
Q

Where do the 4 paranasal sinuses drain? What is their sensory innvervation?

A

Drainage of maxillary, ethmoid + frontal sinus = hiatus semilunaris (middle meatus)
Sphenoid = sphenoethmoidal recess

Ethmoid, frontal + sphenoid = CN Va (ophthalmic)
Maxillary = Cn Vb (maxillary)

25
Q

What are the 2 structures underneath the middle concha in the middle meatus space?

A

Ethmoid bulla

Hiatus semilunaris