Flashcards in 07 - Nose & Paranasal Sinuses Deck (37):
What are the main functions of the nose?
Olfaction, respiration, filter and humidify, drain and eliminate paranasal sinus and nasolacrimal duct secretions
What is the overall structure of the nose?
Bony and cartilaginous components
5 cartilages: 2 lateral, 2 alar and a septal cartilage
Where do the nasal cavities extend between?
Anterior nasal apertures (nares) to the posterior nasal apertures (choanae)
The cavity opens in to the nasopharynx
What forms the roof of the nasal cavity?
Cribiform plate of the ethmoid bone
What forms the floor of the nasal cavity?
Palatal shelf of the maxilla and the palatine bone
What is the sphenoethmoidal recess?
The area between the superior turbinate and the cribiform plate of the ethmoid bone
What happens in a nasal fracture?
History of force to the face, presenting with deformity
Complications include septal haemotoma - avascular necrosis
Saddle nose deformity
What is the structure of the medial and lateral walls of the nasal cavity?
Laterally - turbinates
Medially - nasal septum (septal cartilage, ethmoid, vomer, palatine and maxilla)
What are the passages of the nasal cavities?
Superior, middle and inferior meatus
What is the structure of the ethmoid bone?
Left and right ethmoidal labyrinths
Cribiform plate - holes for the fibres of the olfactory nerve
Bony duct - running through the infundibulum that drains the frontal sinus
What is the arterial supply to the nose?
ECA - facial - superior labial artery
ECA - maxillary - sphenopalatine and greater palatine arteries
ICA - ophthalmic - anterior and posterior ethmoidal arteries
What is the venous drainage of the nose?
Cavernous sinus, facial vein, pterygoid plexus
What is the general sensory Innervation to the septum and lateral walls?
Trigeminal - ophthalmic - nasociliary nerve and branches
Trigeminal - maxillary - nasopalatine (septum) and greater palatine (lateral wall)
What is the sensory innervation to the external nose?
Trigeminal - ophthalmic - external nasal nerve
Trigeminal - maxillary - infra orbital nerve
How does the maxillary sinus drain in to nasal cavity?
What makes up the roof of the maxillary sinus?
Floor of the orbit
What makes up the floor of the maxillary sinus?
Alveolar part of the maxilla
(Roots of the first two molar project in to the sinus)
What are the posterior relations of the maxillary sinus?
Pterygopalatine and infratemporal fossae
The ethmoid sinus is made up of ethmoid air cells between the orbit and nasal cavity. How do the anterior cells drain in to the nasal cavity?
Drain in to the middle meatus via the infundibulum
The ethmoid sinus is made up of ethmoid air cells between the orbit and nasal cavity. How do the middle cells drain in to the nasal cavity?
The ethmoid sinus is made up of ethmoid air cells between the orbit and nasal cavity. How do the posterior cells drain in to the nasal cavity?
How does the frontal sinus drain in to the nasal cavity?
Middle meatus through the frontonasal duct through the ethmoid bone
What structures are in close proximity to the frontal sinuses?
Anterior cranial fossa and the orbit
What structures are in close proximity to the sphenoid sinuses?
Relations with the pituitary fossa and middle cranial fossa
Cavernous sinus and internal carotid artery
Posterior cranial fossa and pons
Roof of nasopharynx
How can infection spread to the anterior cranial fossa?
Via cribiform plate of the ethmoid bone
How can infection spread to the lacrimal apparatus and conjuctiva?
Via the nasolacrimal ducts
How can infection spread to the middle ear?
What is rhinitis?
What are the possible causes?
Inflammation of the nasal mucosa leading to a swelling and increased volume of secretion
Nasal polyps, viral infections, allergies
What are the possible consequences of nasal polyps?
They grow close to the ostiomeatal complex of the nasopharynx
It can lead to nasal obstruction - snoring/obstructive sleep apnoea
What is sinusitis?
What are the possible causes?
Inflammation of the mucosal lining of the sinuses
It can be subacute, acute or chronic
Infection - viral with secondary bacterial infection due to mucous overproduction and nasal obstruction (strep pneumoniae and Haemophilius influenzae)
What drains in to the superior meatus?
Posterior ethmoidal air cells
What drains in to the middle meatus?
Frontal sinuses (anteriorly)
Between = semilunaris hiatus
Maxillary sinuses (posteriorly)
Anterior ethmoidal air cells
What drains in to the inferior meatus?
What are the functions of the turbinate bones?
Disturbs airflow and reduces air speed. Causes turbulence to inspired air - to humidify and warm air due to the large surface area of the turbinates and large vascular mucosa. Also, duct particles and air bacteria are filtered out.
Why might a child with recurrent ear infections benefit from an adenoidectomy?
Due to lots of lymphoid tissue around the opening of the Eustachian tube in to the nasopharynx - removal allows correct drainage of mucous from the tympanic cavity
Why should a patient complaining about toothache be asked about recent upper respiratory tract infections?
the molars are inserted in to the floor of the maxillary sinus. It is hard to distinguish between pain of dental origin and pain from URTIs in the maxillary sinus because they are both innervated by the maxillary division of the trigeminal merve