13. Nose, Nasal Cavity And Paranasal Sinuses Flashcards
The external nose consists of a bony component and a cartilaginous component. What two bones make up the bony component?
Nasal bone.
Frontal process of maxilla.
How can the pituitary gland be accessed in surgery?
Via the nose, then through the sphenoid bone.
What nerve innervates the olfactory mucous membrane lining the external nasal cavity?
CN I - olfactory nerve.
What type of cells line the external nasal cavity?
Respiratory mucous membrane - so pseudo-stratified columnar ciliated epithelium.
What is the role of the respiratory mucous membrane lining the external nose?
Mucous/cilia - filters air.
Watery secretions - humidifies air.
Rich blood supply - warms air.
What drains into the nasal cavity?
Paranasal sinuses.
Nasolacrimal duct draining the eye.
What are the boundaries of the nasal cavity?
Roof - crista galli and frontal bone.
Floor - hard palate.
Medial wall - septal cartilage and nasal septum (vomer bone and perpendicular plate of ethmoid bone).
Lateral wall - meatuses and superior, middle and inferior conchae.
What is a septal haematoma?
Trauma to the nose leading to buckling of the septum and shearing of blood vessels supplying blood to the cartilaginous part of the septum from the overlying perichondrium. Blood accumulated between the perichondrium and cartilage forming a haematoma.
What causes a saddle-nose deformity?
Avascular necrosis of the cartilaginous septum of the nose as a result of an untreated septal haematoma.
Risk increased if develop infection in collecting haematoma.
What cranial nerve carries general sensation from the nasal cavity?
CN V - trigeminal, Va and Vb (mainly).
How do nasal polyps present?
Bilateral, pale or yellow in appearance/fleshy and reddened.
>40 years.
Blocked nose and watery rhinorrhoea, post-nasal drip, decreased smell and reduced taste.
What would a unilateral nasal polyp with or without blood-tinged secretion maybe suggest?
Tumour.
What is rhinitis and what symptoms does it lead to?
Inflammation of the nasal mucosal lining leading to nasal congestion, rhinorrhoea, sneezing, nasal irritation and postnasal drip.
What are the two most common causes of rhinitis?
Simple acute infective rhinitis (common cold).
Allergic rhinitis.
What artists does arterial supply to the nasal cavity arise from?
Branches of the ophthalmic artery and maxillary artery, with anterior anastomoses in the anterior septum.
What is the most common source of bleeding in epistaxis?
Keisselbach’s plexus.
Where do veins from the nasal cavity drain into?
Pterygoid venous plexus, cavernous sinus, facial vein.
What artery in the morse posterior aspect of the nose causes a small minority of nosebleeds, but can be more serious and difficult to treat?
Sphenopalatine artery.
What sinus is most commonly affected in sinusitis?
Maxillary sinus.
How do the paranasal sinuses drain into the nasal cavity?
Via Ostia into a meatus.
What are the names of the 4 pairs of paranasal sinuses? What nerve is each innervated by?
Frontal - Va.
Ethmoid - Va.
Sphenoid - Va.
Maxillary - Vb.
What is acute sinusitis?
Acute inflammation of the lining of a sinus, commonly infective and often secondary to a viral infection of the nasal cavity.
Give 3 signs/symptoms of acute sinusitis
Non-resolving cold or flu-like illness.
Pyrexia.
Blocked nose and rhinorrhoea with or without green/yellow discharge.
Headache/facial pain in the area of the affected sinus, which is worse on leaning forward.
What leads to acute sinusitis?
Primary infection eg rhinitis, leads to reduced ciliary function, oedema of nasal mucosa and sinus Ostia and reduced nasal secretions. Drainage from the sinus is impeded, and stagnant secretions within the sinus become ideal breeding ground for bacteria secondary to infection.