S9) Functional Anatomy of the Nose, Nasal Cavity and Paranasal Sinuses Flashcards Preview

[AMS] Head, Neck & Neuroanatomy > S9) Functional Anatomy of the Nose, Nasal Cavity and Paranasal Sinuses > Flashcards

Flashcards in S9) Functional Anatomy of the Nose, Nasal Cavity and Paranasal Sinuses Deck (52)
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1
Q

Describe the anatomical location of the nasal cavity

A

The nasal cavity extends from the anterior nasal aperture (nostrils) to the posterior nasal aperture (choanae)

2
Q

Identify 5 functions of the nose and nasal cavity

A
  • Sense of smell
  • Route for inspired air
  • Filters inspired air (nasal hair/mucous)
  • Moistens and warms inspired air
  • Resonating chamber for speech
3
Q

Identify and describe the two components of the external nose

A
  • Bony component – nasal bone and frontal process of maxilla
  • Cartilaginous component – two lateral cartilages, two alar cartilages and one septal cartilage
4
Q

What is the most commonly fractured bone of the facial skeleton?

A

Nasal bone (due to prominence)

5
Q

How does inspired air enter the nasal cavity?

A

Inspired air enters via the vestibule which is the area surrounding the anterior external opening to the nasal cavity

6
Q

What lines the surface of the vestibule (of the external nose)?

A
  • Skin
  • Hairs
7
Q

What sort of membrane lines the nasal cavity?

A

Olfactory and respiratory mucous membranes

8
Q

What sort of epithelium is found in the respiratory mucous membrane?

A

Pseudostratified columnar ciliated epithelium

9
Q

What are the actions of the respiratory mucosa?

A
  • Filters (mucous/cilia)
  • Humidifies (watery secretions)
  • Warms (rich blood supply)
10
Q

Which structures drain into the nasal cavity?

A
  • Paranasal sinuses
  • Nasolacrimal duct (drains eye)
11
Q

What are the different boundaries of the nasal cavity?

A
12
Q

Which structures forms the floor of the nasal cavity?

A

The hard palate

13
Q

Describe the structure of the lateral wall of the nasal cavity

A

Bony projections — inferior conchae, middle conchae, superior conchae

14
Q

Explain how the structure of the lateral wall of the nasal cavity is adapted to its functions

A
  • Slows airflow by causing turbulence of airflow
  • Increases surface area over which air passes
15
Q

Which physical features of the nasal cavity allow for the slowing of inspired air?

A
  • Movement from narrow vestibule to large nasal cavity
  • Conchae offer more resistance and disturbs the laminar flow of air
16
Q

Which three structures form the roof of the nasal cavity?

A
17
Q

Which two structures form the medial wall of the nasal cavity?

A
18
Q

Describe the blood supply of the cartilaginous part of the nasal septum

A

Cartilaginous part of septum takes blood supply from overlying perichondrium

19
Q

Why should one always examine for septal haematomas in patients presenting with nasal injury?

A
  • Trauma to nose can buckle the septum and shear blood vessels
  • Blood accumulates between perichondrium and cartilage
20
Q

What is a saddle nose deformity?

A

A saddle nose deformity is a condition due to an untreated septal haematoma which leads to avascular necrosis of cartilaginous septum

21
Q

Besides saddle nose deformity, what is another complication of untreated septal haematoma?

A

An infection in the collecting haematoma can develop and the septal abscess formation further increases likelihood of avascular necrosis of septum

22
Q

Which cranial nerve carries general sensation from the nasal cavity?

A

Trigeminal nerve

23
Q

What are nasal polyps?

A
  • Nasal polyps are fleshy, benign swellings of nasal mucosa which are usually pale/yellow and reddened
  • They are usually bilateral and are common >40 years
24
Q

Identify 5 symptoms of nasal polyps

A
  • Blocked nose
  • Watery rhinorrhoea
  • Post-nasal drip
  • Decreased smell
  • Reduced taste
25
Q

What is rhinitis?

A

Rhinitis is the inflammation of the nasal mucosal lining

26
Q

Identify 5 symptoms of rhinitis

A
  • Nasal congestion
  • Rhinorrhoea (“runny” nose)
  • Sneezing
  • Nasal irritation
  • Postnasal drip
27
Q

Identify two of the commonest causes of rhinitis

A
  • Simple acute infective rhinitis (common cold)
  • Allergic rhinitis
28
Q

Nasal mucosa and blood vessels easily injured.

What is the result?

A

Epistaxis (nosebleed)

29
Q

Describe the arterial supply of the nasal cavity

A
  • Anterior & posterior ethmoidal arteries (branch of ophthalmic artery)
  • Sphenopalatine artery (branch of maxillary artery)
30
Q

What is Kiesselbach’s plexus?

A

Kiesselbach’s plexus (Little’s area) is an area of arterial anastomoses in the anterior nasal septum (most common source of bleeding in epistaxis)

31
Q

Describe the venous drainage of the nasal cavity

A

Venous drainage into pterygoid venous plexus, cavernous sinus and facial vein

32
Q

What is significant about bleeding from the sphenopalatine artery in the nasal cavity?

A
  • Bleeding from the sphenopalatine artery is source for small minority of nosebleeds
  • It is potentially more serious and difficult to treat (posterior & high pressure)
33
Q

What are the paranasal sinuses?

A

The paranasal sinuses are air filled spaces that are extensions of nasal cavity (rudimentary/absent at birth)

34
Q

Identify the 4 different paranasal sinuses

A
35
Q

Describe the structure and function of the paranasal sinuses

A

- Structure: lined with respiratory mucosa (ciliated)

  • Function: secrete mucous, help humidify and warm inspired air, reduce weight of the skull
36
Q

Describe the drainage of the paranasal sinuses

A

All drain into the nasal cavity via small channels called ostia into a meatus (mostly middle meatus)

37
Q

Identify the important anatomical relations of the paranasal sinus

A
  • Nasal cavity
  • Orbit
  • Anterior cranial fossa
38
Q

Describe the specific sensory innervation to the different paranasal sinuses

A
  • Frontal, ethmoidal and sphenoid sinuses ⇒ CN Va
  • Maxillary sinus ⇒ CN Vb
39
Q

In the X-ray below, label the following:

  • Frontal sinuses
  • Orbit
  • Ethmoid air cells
  • Nasal cavity
  • Floor of orbit
A
40
Q

In the X-ray below, label the following:

  • Maxillary sinuses
  • Zygoma
  • Zygomatic process
  • Mandible
A
41
Q

In the diagram below, identify the four paranasal sinuses

A
42
Q

Which sinuses are visible lying in close proximity to the medial wall of the orbits?

A
43
Q

Infections in nasal cavity can involve sinuses (sinusitis).

Which is the most commonly affected paranasal sinus?

A

Maxillary sinus most commonly affected

44
Q

What is acute sinusitis?

A

Acute sinusitis is the acute inflammation of the lining of the sinus which is commonly infective and often secondary to the viral infection of nasal cavity (common cold)

45
Q

Identify 5 signs and symptoms of acute sinusitis

A
  • Non-resolving cold
  • Pyrexia
  • Blocked nose
  • Rhinorrhoea (± green/yellow discharge)
  • Headache/facial pain (area of affected sinus)
46
Q

Why might a patient with sinusitis complain of toothache?

A
  • Roots of upper teeth can sometimes project into maxillary sinus
  • Pain in the maxilla/maxillary sinus can radiate to oral cavity
47
Q

Outline the pathophysiology of acute sinusitis

A
  • Primary infection e.g. rhinitis leads to reduced ciliary function, oedema of nasal mucosa and sinus ostia and increased nasal secretions
  • Drainage from sinus is impeded and secondary bacteria breed in stagnant secretions
48
Q

Identify some important anatomical relations of the nasal cavity

A
  • Paranasal sinus
  • Sphenoid bone
  • Orbit
  • Nasopharynx
  • Oral cavity
49
Q

What is epistaxis?

A

Epistaxis is the common occurrence of bleeding from the nose

50
Q

What are some causes for epistaxis?

A
  • Occur spontaneously
  • Very minor trauma
  • Abnormal coagulation
  • Connective tissue disorders
51
Q

Which groups of patients commonly present with epistaxis?

A
  • Very young (2-10 years)
  • Old (> 50-60 years)
52
Q

Outline the 6 steps in the management of epistaxis

A

⇒ Apply simple compression (cartilage)

⇒ Lean forward

⇒ Cauterisation

⇒ Anterior packing with nasal tampons

⇒ Posterior packing with nasal tampons

⇒ Surgical intervention e.g. embolisation, ligation of blood vessels