Anatomy: Nasal Cavities And Pterygopalatine Fossa Flashcards
Why would you not use adrenaline containing LA’s near the nasal cartilages?
Because adrenaline is a vasoconstrictor. It could potentially constrict the arteries supplying the nasal cartilages to the point that they die without any supply
What are the four main bones of the nasal cavity?
- Nasal bone
- Ethmoid bone
- Perpendicular plate of ethmoid bone
- Vomer bone
The roof of the nasal cavities is formed by what features of the ethmoid bone?
The cribiform plate and Crista galli
The lateral wall of the nasal cavities is formed by what structures?
The superior and middle conchae
The septum of the nasal cavity is formed by what bones?
The perpendicular plate of the ethmoid bone and the vomer
What is the function of the crista galli?
It serves as an attachment point for dura mater, specifically falx cerebri
Where do the ethmoid air cells sit in the nasal cavity?
The lateral border
Which le fort fractures can disrupt the cribifrom plate of ethmoid bone and what is the major concern associated?
Le fort fractures II and III.
There is a danger of infection spreading from nasal cavity and paranasal sinuses into the anterior cranial fossa
What type of mucosa is found in the anterior nasal cavity?
Keratinised stratified squamous epithelium
What type of mucosa is found in the majority of the nasal cavity ( middle and posterior)?
Respiratory epithelium
What type of mucosa is found in a small section and the superior/posterior border of the nasal cavity?
Olfactory mucosa
What do olfactory receptor cells relay?
Nerves associated with sense of smell
Where do receptor cells pass through as the first neurones in the chain?
The cribriform plate of the ethmoid bone
Where do receptor cells pass through after the cribriform plate of the ethmoid bone?
To the olfactory bulbs
What are the olfactory bulbs?
Cell bodies of second neurones
Where are second order neurones passed along to reach the temporal lobe of the brain?
Olfactory tract
What happens to nerve signals once at the temporal lobe?
They are transmitted to higher centres
What can be described as having a Dual blood supply?
The nasal cavity and nose
Where does the blood supply to the nasal cavities originate from?
The external and internal carotid arteries
Which arteries that supply the nasal cavities branch from the external carotid artery?
Facial artery
Maxillary artery
Which arteries that supply the nasal cavities branch from the internal carotid artery?
Ophthalmic artery
Via what arteries does the ophthalmic artery supply the nasal cavities?
Anterior and posterior ethmoidal arteries
Via what arteries does the maxillary artery supply the nasal cavities?
Sphenopalatine and greater palatine arteries
Via what arteries does the facial artery supply the nasal cavities?
Via the lateral nasal branch of the facial artery or septal branch of superior labial artery
What is the importance of kiesselbach’s “little’s” area?
It is an arterial anastomosis on the nasal septum. The most common site for nosebleeds ( epistaxis)
Name the conchae of the lateral wall of nasal cavities
- superior
-middle - inferior
What function do the conchae have?
They warm and humidity air we breathe in
Name the meatus’ of the nasal cavities
- sphenoethmoidal recess
- superior meatus
- middle meatus
- inferior meatus
What are paranasal sinuses?
Air filled spaces within bones
How many sinuses are there in the frontal bone?
Two, called frontal sinuses
How many sinuses are in the two maxillary bones?
Two, maxillary sinuses (one in each bone)
How many sinuses are in the ethmoid bone?
Two sets of ethmoidal air sinuses
How many sinuses are in the sphenoid bone?
Two sphenoidal sinuses
What mucosa lines sinuses?
Mucous-secreting respiratory mucosa
Via what structure does mucous drain into nasal cavities?
Ostia
Where do the frontal sinuses drain to?
The middle meatus
Where do the ethmoidal air cells drain to?
Superior and middle meatus
Where do sphenoidal sinuses drain to?
Sphenoethmoidal recess
Where do the maxillary sinuses drain to?
The middle meatus
What do lacrimal glands produce?
Tears
Where do tears from the lacrimal gland drain to?
Nasolacrimal duct
Where does the nasolacrimal duct drain to?
The inferior meatus
Define sinusitis
The inflammation of the mucosa of paransal sinuses
What nerves cause pain sensation related to sinusitis?
CN V1 and V2
What dental related infection can cause sinusitis?
Dental abscess
Give an example of referred pain in regards to sinusitis
Maxillary sinusitis may present as a toothache of an upper or lower tooth due to the common sensory nerve supply form CN V
‘Holes’ in the recesses and meatuses of the lateral walls that allow drainage of mucosa from paranasal sinuses are known as?
Ostia
What are the two main functions of nasal cavities?
- convey respiratory gases between atmosphere and nasopharynx
- special sense of smell
What is the more common term used for allergic rhinitis?
Hay fever
What structure is termed the “ ganglion of hay fever”?
Pterygopalatine ganglion
Describe the Pterygopalatine fossa
A small, clinically inaccessible space located deep in the face
Where does the maxilla sit in relation to the Pterygopalatine fossae?
Anteriorly
What fissure extends into the Pterygopalatine fossa?
Pterygomaxillary fissure
Where does the Pterygopalatine fossa sit in relation to the infra-temporal fossa?
Medially
In what direction does the Pterygopalatine fossa communicate with the orbit?
Anteriorly
What direction does the Pterygopalatine fossa communicate with the middle cranial fossa?
Posteriorly
in what direction does the Pterygopalatine fossa communicate with the infra-temporal fossa?
Laterally
In what direction does the Pterygopalatine fossa communicate with the nasal cavity?
Medially
Via what structure does the Pterygopalatine fossa communicate with the orbit?
The inferior orbital fissure
Via what structures does the Pterygopalatine fossa communicate with the middle cranial fossa?
Foramen rotundum and pterygoid canal
Via what structure does the Pterygopalatine fossa communicate with the infratemporal fossa?
Ptergyomaxillary fissure
Via what structure does the Pterygopalatine fossa communicate with the nasal cavity?
Sphenopalatine foramen
Where is the Sphenopalatine from and found?
In the lateral wall of the nasal cavity. Between the body of sphenoid and perpendicular plate of palatine bone.
What are the three key structures that the Pterygopalatine fossa contains?
- terminal 1/3rd of maxillary artery
- CN V2/b
- Pterygopalatine ganglion
Which part of the maxillary artery is important in regards to the Pterygopalatine fossa?
The 3rd part
What are the branching arteries of the 3rd part of the maxillary artery?
- Sphenopalatine
- descending palatine
- posterior superior alveolar
- middle superior alveolar
- anterior superior alveolar
Which foramen does the Sphenopalatine artery travel through into the nasal cavity?
The Sphenopalatine foramen
What artery branches from the Sphenopalatine artery once in the nasal cavity?
The descending palatine artery
What does the descending palatine artery supply?
The palate and part of nasal cavity
At what point does the maxillary artery pass through the infra-orbital foramen?
After the branching of the posterior alveolar nerve to supply the posterior upper dentition
What arteries are given off from the infra-orbital foramen?
The middle and anterior superior alveolar arteries
What artery does the maxillary artery arise from?
External carotid artery
What does the Sphenopalatine artery supply?
The nasal cavity
At what point does the maxillary artery become the Sphenopalatine artery?
At the Sphenopalatine foramen
Which nerve does the Sphenopalatine artery travel alongside on the nasal septum?
Nasopalatine nerve
What cranial nerve gives sensory innervates to the nasal cavity?
Trigeminal nerve ( CN V)
What is the somatic sensory supply to the nasal cavity?
The anterior ethmoidal branch of nasociliary (CN V1)
What part of the nasal septum does the anterior ethmoidal nerve innervate?
The posterioinferior nasal septum
What nerves gives somatic sensory innervation to majority of the nasal cavity and nasopharynx?
Nasopalatine nerve (CNV2)
And
Lateral nasal branches of greater palatine nerve (CNV2)
What are the two main nerve branches off the Pterygopalatine ganglion?
- nasopalatine nerve
- greater and lesser palatine
What foramen does CN V2 travel through?
The foramen rotundum
What condition does the autonomic nerve supply to nasal cavities give an explanation for?
Hay fever
Explain the route of preganglionic sympathetic fibres from the brain to the cervical sympathetic ganglion
From the brain, they travel down spinal cord, exit the spinal cord at T1 spinal nerve, then travel superiorly in the sympathetic chain to synapse in the cervical sympathetic ganglion
Where do nerve fibres from the carotid plexus run to?
The deep petrosal nerve
Where does the deep petrosal nerve pass through and to supply what?
Runs and passes through the pterygoid canal, then the Pterygopalatine ganglion to supply the mucosa of nasal cavities
What type of nerve fibres does CN VII carry towards the Pterygopalatine ganglion?
Pre-synaptic parasympathetic nerve fibres
The pre-synaptic parasympathetic nerve fibres synapse at the Pterygopalatine ganglion. True or false?
True
Where do post-synaptic parasympathetic fibres run towards and innervate?
Will head towards the lacrimal gland, to the mucosa of nasal and palatine regions
What two nerves comprise the nerve of pterygoid canal?
The greater petrosal and deep petrosal
What type of nerve fibres does the greater petrosal nerve carry?
Pre-syntactic parasympathetic nerve fibres from CN VII
What type of nerve fibres does the deep petrosal nerve carry?
Post-synaptic sympathetic fibres
Which structure contains both pre-synaptic parasympathetic fibres and post-synaptic sympathetic fibres?
Nerve of pterygoid canal
CN V2/b distributes sympathetic and parasympathetic secretomotor fibres from Pterygopalatine ganglion to what structures?
- lacrimal gland
- mucous glands of nasal cavity
- minor salivary glands of palate