9 - Nose Flashcards
What are the functions of the nose/nasal cavity?
Olfaction Route for inspired air Filtration of inspired air - trapping particles in nasal hair /mucous Moistens and warms inspired air Resonating chamber for speech
How does inspired air enter the nose?
Via the vestibule
Describe the structure of the external nose
Cartilaginous tip
Perimeter of bone, bridge - nasal bone, sides- frontal process of maxillary
What are the divisions of the nasal cavity?
Vestibule
Respiratory region
Olfactory region
Describe the olfactory region of the nasal cavity
Apex of nasal cavity
Lined with olfactory mucous membrane, with olfactory (I) receptors
Describe the respiratory region of the nasal cavity
Majority of nasal cavity
Pseudostratified columnar ciliated epithelium interspersed with goblet cells
What is the function of the respiratory region and how does it achieve this?
Filters inspired air - goblet cells and cilia
Humidifies - watery secretions
Warms - rich blood supply
What drains into the nasal cavity?
Paranasal sinuses
Nasolacrimal duct - why nose runs when you cry
What are conchae and what are their function?
Curved shelves of bone - superior, middle and inferior
Increase surface area and disrupt fast laminar flow of air, making it more turbulent so it spends longer in nasal cavity, allowing it to be humidified
What are the nasal meatuses?
Spaces where paranasal air sinuses and nasolacrimal ducts drain
What forms the roof of the nasal cavity?
Frontal bone
Ethmoid + cribiform plate
Sphenoid bone
What causes a septal haematoma?
Cartlaginous part of septum takes blood from perichondrium
Trauma to nose leads to buckling of septum and shearing of blood vessels
Blood accumulates between perichondrium and cartilage, causes swelling
What is a saddle-nose deformity?
Untreated septal haematoma leading to avascular necrosis of cartilaginous septum
Infection can develop from collecting haematoma, leading to septal abscess
What cranial nerve carries sensation from the nasal cavity?
Trigeminal - maxillary mostly (V2)
What are nasal polyps and what symptoms does it present with?
Benign swellings of nasal mucosa, usually bilateral Symptoms: Decreased ability to smell and taste Post nasal drip Blocked nose Watery rhinorrhoea
How are nasal polyps distinguished from nasal tumours?
Tumours: Unilateral, blood tinged secretions
Polyps: Bilateral, watery secretions
What is rhinitis and what symptoms does it present with?
Inflammation of the nasal mucosal lining
Symptoms: Nasal congesition, rhinorrhoea, postnasal drip
What signs would suggest a foreign body in nasal cavity?
Discharge from one nostril
Smelly, blood stained discharge
Otherwise fine
Child
Describe the blood supply to the nose
Arterial: Opthalmic and maxillary arteries, sphenopalatine artery
Venous: Pterygoid venus plexus, cavernous sinus and facial vein
What is Kiesselbach’s plexus?
Anastomoses in anterior septum - common source of bleeding in epistaxis
What makes epistaxis more serious and why?
Bleeding from sphenopalatine artery, can’t be compressed as is at back of nasal cavity
What are the paranasal sinuses?
Air filled, extensions of nasal cavity - frontal, ethmoid, sphenoid, maxillary
Lined with respiratory mucosa to humidify and warm inspired air, also reduce weight of the skull
Where do the paranasal sinuses drain?
Into nasal cavity via ostia into a meatus, mostly middle meatus
Describe the innervation of the paranasal sinuses
Frontal, ethmoidal and sphenoid - opthalmic (V1) and maxillary (V2)
Maxillary sinus - maxillary nerve (V2)
