HS2-11 Oral and Nasal Cavities Flashcards
What is the role of the nose as the first part of the respiratory system? (2)
warm and humidify air
remove particulate matter from inspired air
The anterior opening of the nasal cavity is called
the anterior nasal aperture (a.k.a. piriform aperture)
The posterior openings of the nasal cavity are called
the choanae
What structure divides the nasal cavity in half?
nasal septum
What structures comprise the nasal septum? (3)
vomer
perpendicular plate of ethmoid
septal cartilage
What forms the roof of the nasal cavity? (4)
nasal bone
frontal bone
ethmoid bone (cribiform plates)
sphenoid bone
What forms the floor of the nasal cavity?
palatine process of maxilla
horizontal plates of palatine bones
What forms the lateral walls of the nasal cavity? (5)
ethmoid (superior + middle conchae)
maxilla
inferior concha (its own bone)
lacrimal bone
palatine bone
What are the four paranasal sinuses?
frontal
maxillary (largest)
ethmoid
sphenoid
What is the function of the paranasal sinuses? (3)
move mucous out into nasal cavity
lighten cranium
resonating chambers for speech
Describe the drainage of the ethmoid sinus.
posterior ethmoid sinus = superior meatus
rest of ethmoid sinus = middle meatus, via hiatus semilunaris
Describe the drainage of the frontal sinus.
middle meatus, via hiatus semilunaris
Describe the drainage of the maxillary sinus.
middle meatus, via hiatus semilunaris
Describe the drainage of the sphenoid sinus.
sphenoethmoidal recess
The superior meatus serves in the drainage of which paranasal sinuses?
posterior ethmoid sinus
The middle meatus serves in the drainage of which paranasal sinuses?
frontal sinus
maxillary sinus
rest of ethmoid sinus
[all drain into middle meatus via hiatus semilunaris]
The inferior meatus serves in the drainage of which paranasal sinuses?
nasolacrimal duct (drainage of tears)
The sphenoethmoidal recess serves in the drainage of which paranasal sinuses?
sphenoid sinus
What provides general sensory innervation to the anterosuperior nasal cavity?
ethmoidal nerves (from nasociliary nerve, from CN V1)
What nerve carries special sensory (smell) fibers to the upper part of the nasal cavity?
olfactory nerve (CN I)
What provides general sensory innervation to the posteroinferior part of the nasal cavity?
CN V2
What innervates the mucous cells of the nasal cavity?
postganglionic parasympathetic secretomotor fibers (that hitch a ride along with sensory branches of CN V2)
What provides blood supply to the anterosuperior portion of the nasal cavity?
ethmoidal branches of ophthalmic artery
What provides blood supply to the posteroinferior portion of the nasal cavity?
sphenopalatine branch of maxillary artery
How do most nosebleeds occur in children?
digital trauma of anastomotic vessels inside the nasal vestibule (Kiesselbach area)
What is the Kiesselbach area?
area inside the nasal vestibule that contains anastomotic vessels prone to digital trauma → nosebleed
How do nosebleeds occur in older patients?
spontaneous rupture of posteriorly-located vessels in the nasal septum
What is the anterior boundary of the oral cavity?
lips + orbicularis oris muscle
What is the lateral boundary of the oral cavity?
cheeks w/ buccinator muscle
What is the posterior boundary of the oral cavity?
fauces (palatoglossus muscle + palatoglossal arch)
What is the superior boundary of the oral cavity?
hard and soft palates
What is the inferior boundary of the oral cavity?
tongue and floor of mouth
How many full teeth are there in an adult?
32 (8 per quadrant)
What is the permanent dentition for each quadrant?
2 incisors
1 canine
2 premolars (bicuspids)
3 molars
What innervates the maxillary dentition?
branches of V2, primarily from infraorbital nerve
What innervates the mandibular dentition?
inferior alveolar branch of V3
The infraorbital nerve is a branch of
CN V2
The inferior alveolar nerve is a branch of
CN V3
What are the two primary muscles found on the floor of the mouth?
mylohyoid
geniohyoid
What structure separates the neck from the oral cavity?
mylohyoid muscle
What provides innervation to the mylohyoid muscle?
mylohyoid nerve (branch of V3)
What is the function of the mylohyoid muscle? (2)
opening mouth (mandibular depression)
swallowing (elevation of hyoid)
Describe the organization of the mylohyoid and geniohyoid muscle in the oral cavity.
geniohyoid is superior to mylohyoid
What innervates the geniohyoid muscle?
branch of ventral ramus of C1
What structure drains the submandibular gland?
submandibular duct, which opens behind the lower incisors
What is sialolithiasis?
stone formation associated w/ salivary glands
In which salivary structure(s) does sialolithiasis most commonly occur?
submandibular ducts
What arteries and nervous structures are found on the floor of the mouth? (4)
lingual nerve
lingual artery
hypoglossal nerve
submandibular ganglion
What is the submandibular ganglion?
parasympathetic ganglion found at level of 3rd lower molar
What is the function of the lingual nerve?
general sensory innervation to anterior 2/3 of tongue
Describe the pathway of parasympathetic innervation to the submandibular and sublingual glands. (5)
preganglionic parasympathetic fibers travel with CN VII
join with chorda tympani and enter infratemporal fossa
join with lingual nerve at floor of oral cavity
synapse at submandibular ganglion
postganglionic fibers go to glands
Why does the surface of the tongue have a corrugated appearance? (2)
papillae
and large vallate papillae posteriorly
What structure divides the tongue into its anterior 2/3 component and posterior 1/3 component?
sulcus terminalis
Differentiate between the anterior 2/3 and posterior 1/3 of the tongue in terms of composition.
anterior 2/3 = muscular
posterior 1/3 = lymphatic
Where is the foramen cecum located?
at apex of sulcus terminalis
What innervates the intrinsic muscles of the tongue?
CN XII
What are the four extrinsic muscles of the tongue?
genioglossus
hyoglossus
styloglossus
palatoglossus
Differentiate between the extrinsic and intrinsic muscles of the tongue in terms of function.
intrinsic = fine control of tongue movements
extrinsic = large tongue movements
What muscle is responsible for protruding the tongue (and therefore maintaining an open airway)?
genioglossus
What is the function of the hyoglossus?
depresses the tongue
What is the function of the styloglossus?
elevates and retracts tongue
What innervates the genioglossus?
CN XII
What innervates the hyoglossus?
CN XII
What innervates the styloglossus?
CN XII
What is the function of the palatoglossus? (3)
elevates posterior tongue, but mostly considered to be a part of soft palate
draws soft palate onto tongue
separates oral cavity from oropharynx
What innervates the palatoglossus?
pharyngeal plexus
What is the anatomical result of a hypoglossal nerve injury? (2)
unilateral paralysis
hemiatrophy of the tongue (eventually)
What is the clinical presentation of someone with a hypoglossal nerve injury? (3)
difficulty speaking
difficulty chewing
difficulty swallowing
How could you determine which side was injured in a hypoglossal nerve injury?
ask patient to stick out tongue → tongue will deviate toward side of injury
Which nerves provide taste and general sensation for the anterior 2/3 of the tongue?
general sensation = lingual nerve (from CN V3)
taste = chorda tympani (from CN VII)
Which nerves provide taste and general sensation for the posterior 1/3 of the tongue?
general sensation = CN IX
taste = CN IX
What nerve provides sensory innervation for the root of the tongue? Note: the root is not the same as the posterior 1/3 of the tongue.
CN X
What structures make up the hard palate? (2)
palatine processes of maxilla
horizontal plates of palatine bones
What are the two components of the soft palate?
anterior aponeurotic component
posterior muscular component
What are the five muscles associated with the soft palate?
palatoglossus
palatopharyngeus
muscle of uvula
tensor veli palatini
levator veli palatini
What is the function of the palatopharyngeus?
elevates pharynx to receive bolus
What is the function of the tensor veli palatini?
opens pharyngotympanic tube
What is the function of the levator veli palatini?
elevates palate to seal separation of oro- and nasopharynx during swallowing
What provides sensory and motor innervation to the soft palate?
motor by pharyngeal plexus (except tensor veli palatini, innervated by CN V3)
sensory by CN V2
What arterial plexus is associated with posterior epistaxis?
Woodruff’s plexus
What innervates the tensor veli palatini?
CN V3
What structures travel through the mandibular canal?
inferior alveolar artery
inferior alveolar vein
inferior alveolar nerve
