Parotid gland + temporal region Flashcards
Parotid gland found?
surrounded by?
duct?
Found near external auditory meatus, extends towards mandible
connective tissue capsule + dense fibrous capsule that extends as stylomandibular ligament
single duct 1 finger’s breadth below zygomatic arch - passes across anterior surface of masseter
note duct crosses anterior surface of masseter
parotid duct pathway?
innervation?
crosses anteriorly over masseter —> sharp medial turn to pierce buccal fat and buccinator —> enter oral cavity at upper 2nd molar
parotid = glossopharyngeal nerve
which nerve is this?
what does it pass through? resulting in?
label branches
facial nerve exits skull via stylomastoid formanen –> passes into parotid gland
It divides the gland into a superficial and deep part —> then divides into branches that leave the gland and pass across the face to supply the muscles of facial expression
what splits parotid gland into superficial and deep part?
pathway + function?
facial nerve exits skull via stylomastoid formanen –> passes into parotid gland
It divides the gland into a superficial and deep part —> then divides into branches that leave the gland and pass across the face to supply the muscles of facial expression
Facial nerve
Spread of facial nerve branches across the face?
The posterior auricular branch passes posterior to the auricle to supply the posterior belly of occipitofrontalis - a muscle of the scalp that is also classed as a muscle of facial expression
posterior auricular branch of facial nerve function?
The posterior auricular branch passes posterior to the auricle to supply the posterior belly of occipitofrontalis - a muscle of the scalp that is also classed as a muscle of facial expression
what pass through the parotid gland deep to the facial nerve?
Superficial temporal vein + maxillary vein (join in parotid gland to form retromandibular vein –> goes on to form external jugular vein)
which artery passes through the parotid gland?
External carotid artery enters the gland and divides to form its terminal branches – the superficial temporal artery that supplies the scalp and the maxillary artery that passes into the infratemporal fossa
deepest structure in parotid gland?
what does it travel with?
The deepest structure in the gland is the auriculotemporal nerve, a branch of the trigeminal nerve
runs with the superficial temporal vessels
diagram of structures related to parotid gland
secretomotor parasymp nerve to parotid gland?
explain how this nerve reaches parotid gland
Secretomotor parasympathetic nerves that supply the parotid gland are from the glossopharyngeal nerve (CN IX)
Main part of glossopharyngeal nerve does not pass onto the face. So parasympathetic nerves to the parotid gland must ‘hitch a lift’ with part of the trigeminal nerve
Glossopharyngeal nerve exits the skull via the jugular foramen
after this, preganglionic parasympathetic nerve fibres leave the main part of the nerve to form a tympanic part that passes into a plexus in the middle ear
From this plexus, a nerve called the lesser petrosal nerve is formed that joins the otic ganglion at the opening of the foramen ovale
Synapse in ganglion then carried by auriculotemporal nerve (branch of the trigeminal nerve)
label lymphatics of face
parotid gland?
parotid gland has lymph nodes that drain the gland and also part of the forehead and orbital region
muscles of mastication?
Innervation?
Function?
Depression?
Four – temporalis, masseter, medial pterygoid and lateral pterygoid
All innervated by the mandibular division of trigeminal (CN V3)
Movements of the mandible – elevation, depression, protrusion, retrusion and lateral sliding
Depression may be by gravity or against force using supra-hyoid muscles
temporalis covered by?
attachments?
function?
Innervation?
temporal fascia
attachments = temporal fossa to —> coronoid process + anterior border of ramus
Anterior and superior fibres elevate mandible
Posterior fibres retract mandible
Innervation = deep temporal nerves (x2) from anterior division of mandibular division of trigeminal nerve (CN V3)
largest muscle of mastication?
temporalis
Masseter attachments?
function?
innervation?
attachments = zygomatic arch to –> lateral part of ramus
Elevate mandible
Masseteric nerve from anterior division of CN V3
lateral pterygoid found?
attachments?
Function?
innervation?
lateral pterygoid + medial pterygoid are both deep to masseter + temporalis, found in infratemporal fossa
upper head = from infratemporal surface of greater wing of sphenoid
lower head = from lateral surrface of lateral pterygoid plate
inserts into neck of mandible + articular disc
protrusion (both) + chewing (one)
Innervation = nerve to lateral pterygoid from anterior division of CNV3
lateral pterygoid
upper and lower head of lateral pterygoid
Medial pterygoid attachments?
function?
innervation?
Superficial head = from tubercle of maxilla
Deep head = from medial surface of lateral pterygoid plate
Inserts into the medial surface of angle of mandible
Assists in elevation
Unusual because nerve supply is from main trunk of mandibular division of trigeminal nerve before it bifurcates into anterior + posterior divisions
Nerve to medial pterygoid from main trunk of the mandibular division of the trigeminal nerve (CNV3)
medial pterygoid
medial pterygoid (below lateral pterygoid)
movements of mandible + muscles involved
Elevation = head of mandible and disc move backward and head rotates on lower surface of disc – temporalis, masseter and medial pterygoid
Depression = head of mandible rotates on undersurface of articular disc and mandible is pulled forward - lateral pterygoid, digastric, geniohyoid, mylohyoid, gravity
Protrusion = articular disc and head of mandible move forward. Movement in upper part of cavity - lateral pterygoid (medial pterygoid assists)
Retrusion = articular disc and head of mandible pulled backward into mandibular fossa – posterior fibres of temporalis
Lateral chewing = protrusion and retrusion combined - pterygoids
divisions of trigeminal nerve?
which one is unique?
three main divisions – ophthalmic, maxillary and mandibular
Ophthalmic and maxillary divisions are purely sensory - only the mandibular division caries both sensory and motor fibres
pathway of mandibular division of trigeminal nerve?
divisions of mandibuar division of trigeminal nerve?
Mandibular division of trigeminal nerve passes through the foramen ovale and divides into branches
Why is CNV3 called carrier nerve?
Part of nerve to medial pterygoid passes through the otic ganglion. No synapse – pass to tensor veli palatini and tensor tympani
Auriculotemporal nerve carries postganglionic parasympathetic fibres from the otic ganglion to the parotid (from glossopharyngeal)
Lingual nerve joined by the chorda tympani carrying parasympathetic fibres from the facial nerve to the submandibular + sublingual glands. Taste fibres from the anterior two thirds of the tongue
label arteries
branches of ECA?
anterior, posterior, deep + terminal branches
terminal = maxillary + superficial temporal behind mandible
posterior branches of ECA?
function?
function = supply scalp deep branch supplies pharynx
Occipital = close to origin of facial artery –> passes under posterior belly of digastric to enter post. triangle —> back of scalp
Posterior auricular = branches at level of upper border of belly of digastric —> scalp
“deep” branch = ascending pharyngeal (branches below occipital on deep surface), ascends between internal carotid + pharynx = supplies pharynx
which branches of ECA are crossed by hypoglossal nerve?
occipital artery
lingual artery
label
branch group?
posterior branches of ECA
Anterior branches of ECA?
origins, pathway + function
Superior thyroid – near origin, runs with external laryngeal nerve. Branch to SCM + superior laryngeal artery
Lingual – opposite tip of greater cornu of hyoid bone, passes deep to hyoglossus, crossed by the hypoglossal nerve. Oral cavity
Facial – above tip of greater cornu, passes deep to posterior belly of digastric. Superior + inferior labial branches and angular artery to face
Terminal branches of ECA?
origins, pathway, function
where does it end?
Superficial temporal – smaller branch, ascends in front of the auricle, divides into anterior + posterior branches which supply the skin over frontal + temporal regions
Maxillary – arises behind neck of mandible, branches to muscles of mastication, tympanic membrane, upper and lower teeth, palate, nasal cavity, nasopharynx and meninges
ECA ends in parotid gland where it splits into superficial temporal artery + maxillary
maxillary artery found?
function?
infratemporal fossa
muscles of mastication, tympanic membrane, upper + lower teeth, palate, nasal cavity, nasopharynx + meninges
