parotid region Flashcards
what 4 things does the parotid region contain?
parotid gland & duct
facial nerve (CN VII)
external carotid
masseter muscle
what are the boundaries of the parotid region?
Superior to angle of mandible, inferior to zygomatic arch
Anterior to auricle & sternocleidomastoid
Posterior to anterior border of masseter
Superficial to ramus of mandible
what is the parotid gland enclosed in? where are its apex (posterior to what?) and base? (parallels what?)
Enclosed in investing layer of deep cervical fascia
Apex-posterior to angle of mandible
Base-parallels zygomatic arch
what is the course of the parotid duct?
Duct courses over superficial surface of masseter, turns inward to pierce buccinator
Ostia opposite 2nd upper molars
what 3 structures are imbedded in the parotid gland? (superficial to deep)?
Parotid plexus of facial nerve: 5 branches
Retromandibular vein
External carotid artery
what type of innervation is the parotid gland? what are the 3 parts (pregang, synapse, post-gang)?
which would the “innervation name” be referring to?
Secretomotor innervation-PSNS
Preganglionic-glossopharyngeal (CN IX)
Synapse: otic ganglion in infratemporal fossa
Postganglionic-auriculotemporal branch of trigeminal (CN V3)
*INNERVATION: PREGANG: GLOSSOPHARYNGEAL CN IX
what are the three branches of the trigeminal? which gives off parotid branches?
CN V (trigeminal) - V1, V2, V3
V1 opthalmic
V2 maxillary
V3: mandibular- auriculotemporal branch - which then gives off parotid branches
boundaries of temporal region (anterior/inferior, posterior, medial, deep, superficial)
Anterior & inferior to temporal lines
Posterior to frontal & zygomatic bones
deep to zygomatic arch
Superior to infratemporal crest of sphenoid
Superficial to frontal, parietal, temporal, & sphenoid bones (pterion)
what is the function of the temporalis investing fascia?
stops at zygomatic arch- acts as a stabilizing force - the muscle pulls the coronoid process upwards and the fascia stabilizes this.
example:if you put the opposite hand on a bench (fascia) to stablize, and the hand on the dumbell pulling up is the muscle - in a lat pull
what are the two processes of the mandible?
anterior: coronoid
posterior: head/condyloid
temporalis muscle: floor
floor: pterion (frontal, parietal, temporal, & sphenoid)
what 4 bones meet to make the pterion?
frontal, parietal, temporal, & sphenoid
boundaries of the infratemporal fossa (medial, lateral, inferior, superior)
Medial to ramus of mandible
Lateral to lateral pterygoid plate of sphenoid
Inferior continuation of temporal fossa, inferior to greater wing of sphenoid
Superior to medial pterygoid muscle
boundaries of infratemporal fossa (posterior, anterior)
Posterior to maxilla
Anterior to mastoid/styloid processes & tympanic plate of temporal bone
what are the 4 communications through the infratemporal fossa? (
- inferior orbital fissure –> orbit
- foramens ovale & spinosum–> mid cranial fossa
- pterygomaxillary fissure –> Pterygopalatine fossa via
- mandibular foramen (on mandible- lower than fossa) –> oral cavity
contents of the infra temporal fossa? (5)
Inferior portion of temporalis muscle Medial & lateral pterygoid muscles Maxillary artery & branches Mandibular branch of trigeminal (CN V3) & branches Otic ganglion
what are the 4 muscles of mastication? what are they all innervated by?
Temporalis Masseter Lateral pterygoid Medial pterygoid In: mandibular division of trigeminal nerve (CN V3)
what is the actions of the temporalis, masseter + pterygoids? what one action are they not the main force in?
Produce movements of TMJ-elevation/depression, protrusion/retrusion, lateral
* Depression: Gravity is main force for this
temporalis muscle: O,I,A,In
O-temporal fossa & deep surface of temporal fascia
I-coronoid process of mandible
A- Elevates & retracts mandible
Inn- deep temporal branch of CN V3
masseter muscle: O,I,A,In
O-maxillary process of zygoma
I-lateral angle & ramus of mandible
A- Elevates mandible
Inn- masseteric branch of CN V3
which masstication muscle has two heads?
lateral pterygoid
superior and inferior heads- two different origins + insertions
lateral pterygoid muscle: O, I
(* originates anterior, Inserts more posterior)
O-superior head: infratemporal surface of GREATER WING SPHENOID;
inferior head: lateral surface of LATERAL PTERYGOID PLATE
I-superior head- inserts on cartilage between head of mandible + mand. fossa (ARTICULAR DISC OF TMJ)
inferior head- inserts on head of mandible directly (CONDYLOID PROCESS/HEAD OF MANDIBLE)
lateral pterygoid muscle- Action and Innervation
A- Protracts mandible (bilateral), moves mandible to contralateral side (unilateral)
Inn- lateral pterygoid branch of CN V3
medial pterygoid muscle- O,I,A,Inn
O-medial surface of lateral pterygoid plate
I-medial angle & ramus of mandible
A- Elevates mandible
Innervated by medial pterygoid branch of CN V3
which muscles elevate the mandible?
temporalis (retracts as well), masseter, and medial pterygoid
what does the TMJ joint do?
Modified hinge joint
- Elevation/depression
- Protraction/retraction
- Pivoting (lateral movements)
TMJ joint space is completely subdivided by what? what does this subdivide the space into? what inserts here?
Joint space completely subdivided by articular disc- creates superior + inferior articular cavities
- Insertion of superior head of lateral pterygoid
TMJ movements:Protraction/retraction occurs between ______ & _____
Elevation/depression & pivoting occur between ____ & ______
protract/retract: temporal bone & disc
elev/depression: disc & condyle
TMJ movements: depression requires simultaneous ____. unilateral protraction generates what ______ _______
Depression requires simultaneous protraction
Unilateral protraction generates contralateral pivoting
what creates the upper curve of the TMJ joint? what creates the lower boundary?
upper curve: manidular fossa
lower boundary: articular tubercle (on zygomatic arch)
maxillary artery is the terminal branch of what? where does it originate?
external carotid.
originates: posterior to neck of mandible
maxillary artery: how many “parts”? how many “branches” ?
3 parts (posterior to anterior) : Mandibular, Pterygoid, Pterygopalatine total: 15 branches
where are the 3 parts of the maxillary artery located? how many branches from each part?
mandibular: posterior to lat pterygoid -5 branches
pterygoid: on the lat. pterygoid (may be sup. or deep) - 4 branches
pterygopalatine: anterior to pterygoid - about 6 branches
fractures of the pteryion can tear what structure? leading to what?
middle meningeal artery - epidural hematoma
maxillary artery: mandibular branch - what are the 2 branches we care about?
middle meningeal + inferior alveolar
what is the course of the middle meningeal (branch of mandibular branch): where does it enter the cranium? where does it go?
Enters via foramen spinosum
ascend between and supplies Dura mater & lateral cranium/calvarium
what is the course of the inf. alveolar (branch of mandibular branch)? what does it continue as?
Enters mandibular foramen
(to supply Mandible & mandibular teeth)
-continues as mental artery with the mental nerve (as exits mandible through the mental foramen)
pterygoid branch (branch of mandibular branch): what 4 branches come off it? what do they supply?
4 branches- supply muscles of mastication
Masseteric-masseter
Deep temporal-temporalis
Pterygoid-pterygoids
*Buccal-buccinator muscle & buccal mucosa + skin of cheek
pterygopalatine branch (branch of mandibular branch): where does it course? what does it supply? (2 parts)
- Enters inferior orbital fissure
supplies: Extraocular muscles, anterior teeth- maxillary canines/incisors - leave through infraorbital foramen
supplies: Infraorbital face
mandibular nerve: enters where? sensory or motor
Enters via foramen ovale
BOTH Sensory & motor branches
Only division of CN V to carry motor fibers
mandibular nerve
what nerves come off the mandibular nerve (CN V3)?
- auriculotemporal- sensory
- inferior alveolar- sensory
- lingual- sensory + secretomotor
- buccal- sensory
* ** misc. Motor branches to muscles of mastication
auriculotemporal nerve (branch of CN V3) : what does it innervate?
-sensory, supplies auricle & temporal region (skin)
also carries Postganglionic secretomotor fibers to parotid gland
inferior alveolar nerve (branch of CN V3): what does it supply? where does it course? what nerve does it give off?
sensory, supplies mandibular teeth
courses through mandibular canal then Mental branch comes out mental foramen + supplies chin
- “Nerve to mylohyoid” (comes off before it enters mandible)
lingual nerve (branch of CN V3): what 2 things does it supply? what nerve joins it?
lingual nerve: pressure/touch to anterior tongue chorda tympanii (from CN VII) joins: taste to anterior tongue
lingual: secretomotor to submandibular & sublingual glands
buccal nerve (branch of CN V3): what does it supply?
sensory, supplies skin & mucosa of cheek
when you bite your cheek or when your cheek is pinched by grandma
otic ganglion: what is it inferior to? medial to? what kind of nerve function does it carry?
Inferior to foramen ovale, medial to CN V3
Parasympathetic, secretomotor to parotid
pre + post synaptic neurons to/from otic ganglion
Presynaptic neurons from glossopharyngeal (CN IX)
Postsynaptic neurons travel in auriculotemporal branch of CN V3
visceral motor (PSNS) innervation of parotid gland: pregang PSNS from what nerve? where does it course/synapse? postganglionics in what nerve?
Preganglionic PSNS arrive via lesser petrosal nerve (from CN IX)
course: Lesser petrosal enters fossa via foramen ovale
–> Synapse in otic ganglion
Postganglionic neurons reach gland via auriculotemporal branch of CN V3
inf alveolar block: what nerve is the goal? what nerve is at risk? what muscle is injected?
Dental anesthesia- Mandibular teeth
inf alveolar nerve (w/ Lingual nerve-tongue numbness)
Risk for facial nerve injury
Injection into medial pterygoid
how can tetanus cause lockjaw?
causes Intense spasm of lateral pterygoid
what is frey’s syndrome?
gustatory sweating (from parotid surgery)
–> Aberrant regeneration of postganglionic parasympathetic neurons
Smell/taste provokes sweating, warmth, redness
