The Nose, Nasal Cavity and Paranasal Sinuses Flashcards
Through which bone would a surgeon need to drill to gain access to the pituitary gland?
sphenoid
What is the function of the nose and nasal cavity?
Olfaction
Filtering
Humidifying inspired air
Warms air – highly vascular
Drainage of secretions from paranasal sinuses and nasolacrimal ducts
Resonating chamber for speech
What is the vestibule?
Inner part of the external nose
Lining = skin, hair, sebaceous glands
What makes up the bony part of the external nose?
Nasal bone
Frontal process of maxilla
Describe the anatomy of the nasal cavity?
Lining = mucous membrane
Conchae = superior, middle, inferior
Meatus = space under bony shelf, passage to sinuses
What cranial nerve allows for olfaction?
CN I
What lines the nasal cavity?
Olfactory mucous membrane = smell
Respiratory mucous membrane = pseudostratified columnar ciliated ep, filters, humidifies, warms
What are the boundaries of the nasal cavity?
Medial = perpendicular plate of ethmoid bone, vomer
Lateral = maxilla, conchae
Roof = frontal bone, sphenoid bone, nasal bone, cribiform plate
Floor = hard palate
The irregular nature of the lateral wall in the nasal cavity, enables what?
Turbulent air flow
Increased surface area
Outline the vascular supply to the nasal cavity
Sphenopalatine artery = bleeding potential more serious/diff to treat
Greater palatine artery
Superior labial
Posterior ethmoid
Anterior ethmoid
What are paranasal sinuses?
Reduce weight of skull = filled with air
Humidify and warm inspired air
Mucus from here drains to nasal cavity
Name the paranasal sinuses
Maxillary – largest
Frontal
Ethmoidal
Sphenoid
What are the paranasal sinuses lined with?
Respiratory mucosa = ciliated pseudostratified columnar with goblet cells
What CN carries general sensation to the nasal cavity?
Trigeminal N – ophthalmic, maxillary
Describe nasal polyps
Fleshy, benign swellings of nasal mucosa
Usually bilateral
Blocked nose and water rhinorrhoea
Post-nasal drip
Decreased smell/reduced taste
What is the nervous supply to the paranasal sinuses
Va (trigeminal ophthalmic) = frontal, ethmoidal, sphenoid
Vb (trigeminal maxillary) = maxillary
Define epistaxis
Nose bleed
What is the most common site for nose bleeds?
Keisselbacks plexus
Arterial supply to the nasal cavity arises from where?
Branches of ophthalmic artery and maxillary artery
Outline the venous drainage from the nasal cavity
Drains into the pterygoid venous plexus, cavernous sinus and facial vein
What is rhinitis?
Infam of mucosal lining
Nasal congestion, rhinorrhoea, sneezing, nasal irritation, post-nasal drip
Causes = viral common cold, allergic rhinitis
Describe a nasal fracture
Nasal bone is most prone to fracture
Often hidden by swelling = wait to subside
What is a septal haematomas?
Blood collects in space between cartilaginous septum and its perichondrium = no blood supply
Untreated = irreversible avascular necrosis = distortion = saddle-nose deformity
Examine = swelling from medial part of nasal cavity
Describe sinusitis
Inflam of the lining of the sinuses
Primary infection = mucosal oedema = impedance of ciliary function = increased mucosal secretions = obstruction to drainage from a paranasal sinus = accumulation of mucosal secretions = secondary infection by bacteria
Maxillary sinus particular prone
Self-limiting
