S9) Functional Anatomy of the Nose, Nasal Cavity and Paranasal Sinuses Flashcards
Describe the anatomical location of the nasal cavity
The nasal cavity extends from the anterior nasal aperture (nostrils) to the posterior nasal aperture (choanae)
Identify 5 functions of the nose and nasal cavity
- Sense of smell
- Route for inspired air
- Filters inspired air (nasal hair/mucous)
- Moistens and warms inspired air
- Resonating chamber for speech
Identify and describe the two components of the external nose
- Bony component – nasal bone and frontal process of maxilla
- Cartilaginous component – two lateral cartilages, two alar cartilages and one septal cartilage
What is the most commonly fractured bone of the facial skeleton?
Nasal bone (due to prominence)
How does inspired air enter the nasal cavity?
Inspired air enters via the vestibule which is the area surrounding the anterior external opening to the nasal cavity
What lines the surface of the vestibule (of the external nose)? and what type of cells line it
- Skin
- Hairs
- stratified squamous
What sort of membrane lines the nasal cavity?
Olfactory and respiratory mucous membranes
What sort of epithelium is found in the respiratory mucous membrane?
Pseudostratified columnar ciliated epithelium
What are the actions of the respiratory mucosa?
- Filters (mucous/cilia)
- Humidifies (watery secretions)
- Warms (rich blood supply)
Which structures drain into the nasal cavity?
- Paranasal sinuses
- Nasolacrimal duct (drains eye)
What are the different boundaries of the nasal cavity?
Which structures forms the floor of the nasal cavity?
The hard palate
Describe the structure of the lateral wall of the nasal cavity
Bony projections — inferior conchae, middle conchae, superior conchae
Explain how the structure of the lateral wall of the nasal cavity is adapted to its functions
- Slows airflow by causing turbulence of airflow
- Increases surface area over which air passes
Which physical features of the nasal cavity allow for the slowing of inspired air?
- Movement from narrow vestibule to large nasal cavity
- Conchae offer more resistance and disturbs the laminar flow of air
Which three structures form the roof of the nasal cavity?
Which two structures form the medial wall of the nasal cavity?
Describe the blood supply of the cartilaginous part of the nasal septum
Cartilaginous part of septum takes blood supply from overlying perichondrium
Why should one always examine for septal haematomas in patients presenting with nasal injury?
- Trauma to nose can buckle the septum and shear blood vessels
- Blood accumulates between perichondrium and cartilage
What is a saddle nose deformity?
A saddle nose deformity is a condition due to an untreated septal haematoma which leads to avascular necrosis of cartilaginous septum
Besides saddle nose deformity, what is another complication of untreated septal haematoma?
An infection in the collecting haematoma can develop and the septal abscess formation further increases likelihood of avascular necrosis of septum
Which cranial nerve carries general sensation from the nasal cavity?
Trigeminal nerve
ophthalmic and maxillary
What are nasal polyps?
- 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
Identify 5 symptoms of nasal polyps
- Blocked nose
- Watery rhinorrhoea
- Post-nasal drip
- Decreased smell
- Reduced taste
What is rhinitis?
Rhinitis is the inflammation of the nasal mucosal lining