Nasal Cavity, Paranasal Sinuses, and Pterygopalatine Fossa Flashcards
What bony and cartilaginous elements constitute the skeleton of the nose?
Bony part of external nose- two nasal bones
frontal processes of maxilla
nasal part of frontal bone
Cartilaginous part of external nose- 2 lateral nasal cartilages
2 greater alar cartilages
Bony portion of nasal septum- perpindicular plate of ethmoid
vomer
Cartilaginous part of nasal septum-nasal septal cartilage
Where are nasal conchae located? What is their function? What is the space beneath each conchae
termed? What drains into each of these spaces?
The conchae are on the lateral wall of the nasal cavity where they increase the surface area and help to warm and humidify air as it comes in.
The space beneath each one is called a meatus.
Inferior meatus- opening of nasolacrimal duct
Middle Meatus-
Semilunar hiatus-drains frontal sinuses and maxillary sinuses and anterior ethmoidal cells
Ethmoidal bulla- drains middle ethmoidal cells
uncinate process
Outline the innervation of the nasal cavity-both special sense of smell and somatic sensation.
- Olfactory Nerves - special sense of smell
- Opthalmic Nerves to anterior/posterior ethmoidal nerves.
- Maxillary Nerve- Nasopalatine n. to septum
Greater palatine and posterior nasal branch to lateral nasal walls.
What travels through the pterygopalatine fossa?
-3rd segment of maxillary artery
-CN V2 Maxillary Nerve
-Automonic Fibers: Nerve of Pterygoid Canal
Parasympathetics from CN VII
Sympathetics
-Pterygopalatine ganglion
Where does V2 travel after it exits the foramen rotundum?
It travels directly into the pterygopalatine fossa and then exits the pterygopalatine fossa via the infraorbital fissure where it changes its name to infra-orbital nerve.
Trace the pathway by which parasympathetics reach the nasal septum, the lateral nasal wall, the
hard and soft palate. How do parasympathetics reach the lacrimal gland?
Cell bodies are located in the superior salivatory nucleus, then the pre-ganglionic fibers travel along the greater petrosal nerve (a branch of CN VII) to synapse in the pterygopalatine ganglion. From there they exit via the sphenopalatine foramen as part of the posterolateral nasal branches and the nasopalatine nerve to supply the nasal cavity. Other fibers exit the palatine canal on the greater palatine nerve to supply the hard palate while others exit the palatine canal with the lesser palatine nerve to supply soft palate.
In order to get to the lacrimal gland, post-ganglionic sympathetics hitch a ride on CN V2 to zygomatic nerve to zygomaticotemporal nerve, then ride on a communicating branch to the lacrimal nerve of CN V1 and travels on lacrimal nerve to the gland.
Trace the pathway of the greater petrosal nerve (describe its course in the temporal bone, back
into the middle cranial fossa, then through foramen lacerum to reach the pterygoid canal).
The greater petrosal nerve branches off the facial nerve distal to the geniculate ganglion. It exits the petrous temporal bone via the hiatus of the facial canal near foramen lacerum. From there, it enters the pterygoid canal of sphenoid. In the canal it joins with deep petrosal nerve to form nerve of pterygoid canal. This nerve enters the posterior pterygopalatine fossa and parasympathetic fibers synapse in the pterygopalatine ganglia.
Where do the fibers of the greater petrosal nerve synapse?
Pterygopalatine ganglia
What bones contribute to the lateral wall, roof, floor, and medial wall of the nasal cavity?
Roof (from ant to post) = nasal, frontal, ethmoid (features cribiform plate of ethmoid), and sphenoid
Floor (ant to post) = palatine process of maxillary + horizontal plate of palatine
Lateral wall = maxilla (ant), sphenoid + palatine (post) with 3 concha superimposed in middle (sup and middle of ethmoid + inferior concha bone)
Medial wall = nasal septum!
What is the primary blood supply to the nasal cavity?
The Sphenopalatine A (from maxillary a) supplies largest amount of blood to nasal cavity.
[Other 3 arteries are Ant/Post Ethmoidal aa, Greater palatine a (hard palate), and branches of facial artery]
Describe the location of each paranasal sinus and how they drain into the nasal cavity.
4 paranasal sinuses, each named for the bones in which they reside:
-Sphenoid: is unevenly divided by nasal septum into L/R sinus. Drains into Sphenoethmoidal recess
- Frontal: (3) step draining via Frontonasal duct into Ethmoidal infundibulum into Semilunar hiatus
- Maxillary: largest and pyramid-shaped. Drains into Semilunar hiatus.
-Ethmoidal (air cells): comprised of Ant, Middle, and Post ethmoidal cells. Drainage:
Ant - Ethmoidal infundibulum into semilunar hiatus
Middle - DIRECTLY into middle meatus via Ethmoidal bulla
Post - DIRECTLY into Superior Meatus
Which division of the ethmoidal air cells does NOT drain into the middle nasal meatus?
Posterior ethmoidal cells. They drain into the superior meatus
What 4 paranasal sinuses (or divisions) drain into the middle meatus? Which drain directly?
The frontal, maxillary, anterior ethmoidal, and middle ethmoidals all drain into the middle meatus. The frontal, maxillary, and ethmoidal cells all drain into the semilunar hiatus. The middle ethmoidal cells open directly into the middle meatus.
Where is the pterygopalatine fossa (PPF) located? What 3 bones is it situated between?
PPF is a small, pyramidal space inferior to the apex of the orbit. It is situated between the maxilla, sphenoid, and palatine bones.
What are the boundaries of the pterygopalatine fossa (anteriorly, posteriorly, laterally, medially, superiorly (roof), and inferiorly (floor)?
Anterior: Maxilla (its posterior border)
Posterior: Pterygoid process of Sphenoid bone
Lateral: infratemporal fossa
Medial: perpendicular plate of palatine bone
Roof: greater wing of sphenoid bone
Floor: pyramidal process of palatine bone
