Nose & Sinus Anatomy and Physiology Flashcards

1
Q

Function of nasal airway?

A
  • Warm and humidify inhaled air
    • Turbinates and septum
      • Laminar flow
    • Mucosal lining
      • Humidification
      • Sinuses are a reservoir of warm humid air
  • Important for neonates
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2
Q

How is the nasal airway able to act as immune barrier?

A
  • Specialised nasal mucosal lining
    • First 1/3 stratified squamous epithelium
      • Nasal hairs trap large particulates
    • Posterior 2/3 pseudostratified columnar epithelium
      • Cilia allows mucus to travel 2.5cm/min
      • Goblet create sticky mucus that trap pathogens
      • Mucus contains IgA, IgE (allergies), lysozymes, alkaline
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3
Q

What is the structure of the nasal epithelium?

A
  • First 1/3 stratified squamous epithelium
    • Nasal hairs trap large particulates
  • Posterior 2/3 pseudostratified columnar epithelium
    • Cilia allows mucus to travel 2.5cm/min
    • Goblet create sticky mucus that trap pathogens
    • Mucus contains IgA, IgE (allergies), lysozymes, alkaline
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4
Q

What does mucus contain?

A
  • Mucus contains IgA, IgE (allergies), lysozymes, alkaline
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5
Q

Through what does smell occur?

A
  • Olfactory nerve
  • Through cribrifom plate
  • Olfactory mucosa
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6
Q

What allows drainage and aeration of middle ear?

A

Drainage and aeration of middle ear:

  • Eustachian tube
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7
Q

What are some functions of sinuses?

A
  • Reservoir of warm humid air
  • Lighten skull
  • Crumple zones
  • Vocal resonance
  • Lined with same mucosa (immune barrier)
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8
Q

What are some of the external subunits of the nose?

A
  • Columella
  • Tip and supratip
  • Dorsum
  • Nasion
  • Glabella
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9
Q

What are examples of common nasal trauma?

A
  • Broken bones
    • Move back before they heal
  • Broken/bent cartilage
    • Cannot be easily unbent
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10
Q

What fors the following of the nasal passage:

  • roof
  • walls
  • floor
A

Roof:

  • Skullbase/cribiform plate

Walls:

  • Turbinates

Floor:

  • Hard palate
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11
Q

What are some internal nasal associated structures?

A
  • Paranasal sinuses
  • Orbits
    • Lamina papyracea
    • Eustachian tube
    • Adenoids
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12
Q

What is the midline of the nose?

A

Septum

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13
Q

What is the septum formed from?

A

Bone and cartilage:

  • Septal cartilage
  • Vomer
  • Perpendicular plate of ethmoid
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14
Q

Where does nasal cartilage get blood supply from?

A
  • Poor blood supply
  • Gets blood supply from mucosa overlying it
  • Relevant in septal haematoma
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15
Q

Septal haematoma - pathology

A

Septal haematoma = blood collects in the septum

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16
Q

Septal haematoma - aetiology

A
  • Post trauma
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17
Q

Septal haematoma - presentation

A
  • Almost always bilateral
  • No blood supply to septum
  • Causes septum necrosis, leading to perforation so needs to be drained as soon as possible
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18
Q

What are turbinates?

A

Bony skull like projections from lateral wall of the nose:

  • Superior
  • Middle
  • Inferior
19
Q

What is the function of turbinates?

A

Increases surface area of the nose:

  • Humidification and warming of air
20
Q

What are turbinates covered in?

A

Covered in erectile tissue:

  • Day to day cycling
  • Respond to temperature
21
Q

What opens underneath turbinates?

A

Sinuses and nasolacrimal duct open underneath turbinates:

  • Meatus
  • Correspond to turbinate they are under
22
Q

What is the nasolacrimal duct?

A

Drainage pathway of lacrimal secretions (tears)

From lacrimal sac

23
Q

Where does nasolacrimal duct open?

A

Opens under inferior turbinate

Inferior meatus

24
Q

What are the paranasal sinuses?

A
  • 2 frontal
    • Behind eyebrows
    • Drains into frontal recess
    • Drains via middle meatus
    • Lateral to middle turbinate
  • 2 maxillary
    • Behind each cheek
    • Drains via middle meatus
  • Sphenoid
    • Drains via the sphenoethmoidal recess
    • Optic nerve runs above it
    • Internal carotids either side
    • Pituitary is posterior
    • This is why severe sinusitis can cause neurological problems
  • Ethmoid air cells (anterior and posterior)
    • Honeycomb structure between eyes
    • Middle turbinate turns at the back of the nose to attach to the lateral nasal wall
      • This turn is called the ground lamella
      • Anterior to this is the anterior ethmoid which drains into the middle meatus
      • Posterior to this is the posterior ethmoids which drains into the superior meatus
    • Clinical relevance is that infections spreads to orbit causing periorbital/orbital cellulitis
25
Q

Where are the frontal sinuses located?

A
  • Behind eyebrows
  • Lateral to middle turbinate
26
Q

What do the frontal sinuses drain and drain via?

A
  • Drains into frontal recess
  • Drains via middle meatus
27
Q

Where are the maxillary sinuses located?

A
  • Behind each cheek
28
Q

What do the maxillary sinuses drain via?

A
  • Drains via middle meatus
29
Q

What does the sphenoid sinus drain via?

A
  • Drains via the sphenoethmoidal recess
30
Q

What structures are found around the sphenoid sinus?

A
  • Optic nerve runs above it
  • Internal carotids either side
  • Pituitary is posterior
  • This is why severe sinusitis can cause neurological problems
31
Q

Where are the ethmoid air cells?

A
  • Honeycomb structure between eyes
32
Q

What is the ground lamella?

A
  • Middle turbinate turns at the back of the nose to attach to the lateral nasal wall
    • This turn is called the ground lamella
    • Anterior to this is the anterior ethmoid which drains into the middle meatus
    • Posterior to this is the posterior ethmoids which drains into the superior meatus
33
Q

What does the anterior and posterior ethmoid air cells drain via?

A
  • Anterior to this is the anterior ethmoid which drains into the middle meatus
  • Posterior to this is the posterior ethmoids which drains into the superior meatus
34
Q

What is the clinical relevence of the ethmoid air cells anatomy?

A
  • Clinical relevance is that infections spreads to orbit causing periorbital/orbital cellulitis
35
Q

What sinuses drain via the following:

  • middle meatus
  • superior meatus
  • sphenoethmoidal recess
  • inferior meatus
A
  • Frontal, anterior ethmoids and maxillary
    • Middle meatus
  • Posterior ethmoids
    • Superior meatus
  • Sphenoid
    • Sphenoethmoidal recess
  • Nasolacrimal duct
    • Inferior meatus
36
Q

What is sinusitis?

A

Sinusitis = inflammation of the sinuses

37
Q

Sinusitis - aetiology

A

Can be due to allergies or infection

38
Q

Sinusitis - complications

A

Normally self limiting (acute being less than 12 weeks)

Occasionally is chronic:

  • Inflammation blocks sinus drainage
  • Mucus in sinus gets infected causing more inflammation
  • Can lead to polys causing further blockage
39
Q

Sinusitis - treatment

A
  • Medical management
    • ​Remove allergic triggers, with or without antihistamines
    • Treat infection
    • Reduce inflammation
      • Steroids (long term nasal spray)
  • Surgery
    • Remove polyps
    • Open up sinus drainage pathways
    • Risks
      • Damage lamina papyracea (orbital damage)
      • Damage to skull base (cerebrospinal fluid leak and meningitis)
40
Q

What are risks of surgery for sinusitis?

A
  • Damage lamina papyracea (orbital damage)
  • Damage to skull base (cerebrospinal fluid leak and meningitis)
41
Q

Where does the nose receive blood supply from?

A

Has excellent blood supply from internal and external carotid

External:

  • Sphenopalatine artery (via maxillary)
  • Also greater palatine (via maxillary) and superior labial (via facial)

Internal:

  • Anterior and posterior ethmoidal artery (via ophthalmic)
42
Q

Describe the nasal innervation of the nose?

A

Almost all trigeminal nerve (CN V):

  • V1 ophthalmic
  • V2 maxillary

Sensation is internal and external

43
Q

What is found in the post-nasal space?

A

Adenoids:

  • Waldeyers ring

Eustacian tube opening

Soft palate muscles attach to Eustachian tube to open it during swallow:

  • Equalise middle ear