Session 7: Applied Anatomy of the Nose, Nasal Cavity and Paranasal Sinuses Flashcards
Functions of nose and nasal cavity.
Sense of smell
Provides a route for inspired air
Filters inspired air by trapping particles in nasal hair and mucous.
Moistens, humidifies and warms inspired air.
Resonating chamber for speech
Allows drainage of secretions from paranasal sinuses and nasolacrimal ducts.
What can the nose be divided into?
External nose, nasal cavity and nasopharynx.
What are the two parts of the external nose?
Cartilaginous part
Bony part
What forms the root of the external root?
The frontal processes of the maxillae and two nasal bones.
What injuries are the nose susceptible to?
Septal haematomas
Septal deviations
Nasal bone fractures
Explain the gross structure of the nasal cavity.
It extends from the nostrils anteriorly known as the anterior nasal apertures to the posterior nasal apertures which are also known as choanae.
It also has a roof, a floor, and two walls lateral and medial.
What is the medial wall of the nasal cavity formed by?
Consist of a bony and cartilaginous part.
Formed by the nasal septum.
What does the nasal septum consist of?
The perpendicular plate of the ethmoid bone, septal cartilage, vomer.
What does the cartilaginous part of the septum rely on for its blood supply?
The overlying perichondrium
Where does inspired air first enter the nose?
The vestibule
What is the vestibule lined with?
Skin containing sebaceous/sweat glands and hair.
It’s keratinised stratified squamous epithelium.
What does the nasal cavity communicate with posteriorly?
The nasopharynx
How can the lateral wall of the nasal cavity be described?
Irregular
What makes the lateral wall of the nasal cavity irregular?
Bony projections also known as conchae.
State the conchae of the nasal cavity.
Superior
Middle
Inferior
What are the superior and middle conchae made of?
They are part of the ethmoid bone.
What is the inferior conchae made of?
It is a bone on its own.
What are found between the conchae?
The superior, middle and inferior meatuses of the nasal cavity.
What are the functions of the conchae and meatuses of the nasal cavity?
Slows airflow by causing turbulence of airflow.
Increases surface area of which air passes.
The paranasal air sinuses and orbit communicate with the nasal cavity through openings in the lateral wall. There are openings under the meatuses that allow for drainage.
Explain what happens in a septal haematoma.
Usually due to blunt trauma to the nose. The perichondrium is stripped off the cartilaginous part of the nasal septum. Blood collects between those parts called sub-perichondrial haematoma of the septum.
Complications of septal haematoma.
The septal cartilage relies on the perichondrium for its blood supply. If there is a septal haematoma the cartilage doesn’t get its blood supply. This leads to ischaemia of the cartilage.
If the septal haematoma is not recognised and not treated it can lead to irreversible necrosis and what is called a saddle-nose deformity.
Another thing that can develop is infection in the collecting haematoma which can lead to a septal abscess. This further increases likelihood of avascular necrosis and saddle deformity.
Which cranial nerve carries general sensation from the nasal cavity?
Trigeminal nerve
What nerve makes a snotty and runny nose?
The facial nerve
What is the nasal cavity lined with?
Mucous membrane that is highly vascular
What types of mucous membrane is the nasal cavity lined with?
Olfactory mucous membrane
Respiratory mucous membrane
What can be found in the olfactory mucous membrane?
It houses olfactory receptor neurones for smell