Question | Answer |
Trace the path of the parotid duct | 1.) Comes out from anterior edge of parotid gland inferior to zygomatic arch.
2.) Courses anterior &superficial to masseter
3.) Dives deep to buccinator fat pad & into buccinator muscle
4.) Opens opposite to 2nd molar into oral cavity |
What is the parotid fascia an extension of? What does it split into? | Deep cervical fascia. A superficial & deep layer. |
Where does the partoid fascia attach? | Superficial layer attaches to zygomatic arch with extensions going into the gland. Both layers fuse with the muscle fascia around it. |
How far does the parotid gland extend superficially? | Up to zygomatic arch superiorly.
From external acoustic meatus to mastoid process & anterior upper SCM posteriorly.
Down to the angle of the mandible inferiorly. |
What are the borders of the parotid bed? | Anterior: ramus of mandible
Posterior: mastoid process w/SCM & posterior digastric
Medial: styloid process & the 3 muscles attached there
Superior: temporomandicular joint & ext acoustic meatus
Deep: internal jugular vein & internal carotid & CN9-12 |
What structures lie within the parotid gland from superficial to deep? | CN7 (facial), retromandibular vein & ext carotid artery with a few of their branches/tributaries. |
What does the facial nerve divide into within the parotid gland? | temporofacial & cervicofacial divisions that divide into the 5 main branches. |
What tributaries of the retromandibular vein are contained in the parotid gland? | Superficial Temporal & Maxillary |
What branches of the exteral carotid artery come off in the parotid gland? | Posterior auricular, superficial temporal w/transverse facial coming off it & maxillary. |
We know facial nerve is within the parotid gland, but what other nerve goes thru it & where in the gland? | Auriculotemporal nerve (off V3 of trigeminal). It goes thru superior part of parotid gland. |
How is the parotid gland divided into a superficial and deep lobe? | The facial nerve divides the gland into superficial & deep lobes. |
How does the parotid gland get its blood? Where does it go when it's done with it? | From the branches off the external carotid. The blood then drains into the large veins, like the superficial temporal & maxillary into the retromandibular. |
How does the parotid gland get its sensory innervation? What about the superficial tissue associated with it? | Trigeminal V3 branch: auriculotemporal
Fibers go from gland back to trigem ganglion.
Superficial tissues get sensation from Great Auricular (C2,3). |
What is the path of sympathetic supply to the parotid gland? | pregang sympathy cell bodies in lateral horn of T1-T2 > ventral roots > white rami > sympathy chain > postgang neurons in superior cervical ganglion > external carotid plexus > parotid gland....OR |
It can go from sympath plexus onto MMA and go thru otic ganglion with auriculotemporal nerve to get to parotid. | |
What is the path of parasympathetic supply to the parotid gland? | pregang parasympath cell bodies in inferior salivatory nucleus in medulla > CN9 > out jugular foramen > tympanic nerve > tympanic plexus in middle ear > leaves as lesser petrosal > synapse in otic ganglion > auriculotemporal nerve to parotid gland |
What does the condylar head of the mandible articulate with? | The mandibular/glenoid fossa & articular tubercle of temporal bone. Or the cranium if you wanna go big pic general. |
What type of joint is the TMJ? What are the articulating surfaces covered with? | A DOUBLE synovial joint. Doubles as both a hinge AND gliding joint. The articulating surfaces are covered in fibrocartilage. |
What are the TMJ joint structures? | articular disc, capsule, synovial membrane & lateral ligament |
What does the articular disc of TMJ do? What does it attach to? | Divides TMJ into 2 joint cavities. Attaches to fibrous joint capsule around its edges & the TENDON of lateral pterygoid muscle anteriorly. |
What is important about the capsule of the TMJ? Where does it attach? | It's thin & loose so joint can move around. It attaches along mandibular foss & articular tubercle & down to neck of condyle. |
Where are the synovial membranes of the TMS? | One lines joint capsule above articular disc & another lines the one below. |
What does the lateral ligament of the TMJ do? | Strengthens joint capsule anterolaterally which helps prevent posterior displacement of head of mandible. |
Where does the lateral ligament attach? | Attaches to inferior surface of zygomatic arch & goes down obliquely to attach to lateral & posterior NECK of mandible. |
What are the extracapsular ligaments of the TMJ? What makes them extracapsular? | stylomandibular ligament & sphenomandibular ligament. they are outside the TMJ & connect mandible to cranium. |
What is the stylomandibular ligament & what does it attach? | Is thickening of parotid fascia. Attaches styloid process to angle of mandible. |
What does the sphenomandibular ligament do? Where does it attach? | Limits inferior movement of mandible. Attaches superiorly to spine of sphenoid & down to lingual on medial aspect of mandibular ramus. |
What passes between the sphenomandibular ligament and the mandible? | The maxillary vessels & inferior alveolar vessels & nerves. |
What movements are permitted at the TMJ? | Depression, elevation, protrusion, retraction & lateral movement. |
Why does the jaw move forward when you open it really widely? Where does hinge movement occur? Where does gliding movement occur? | Mandibular condyle & articular disc move forward b/c posteriorly, space is limited. Hinge is btwn condylar head & articular disc. Gliding is btwn articular disc & temporal bone. |
What muscles act on the TMJ? | Muscles of mastication, suprahyoid, infrahyoid & platysma. |
What innervates the TMJ? So how does pain spread from TMJ? | Auriculotemporal & masseteric branches of V3. It goes to ears, temporal region & cheeks. |
What is the blood supply to the TMJ? | Branches off maxillary and superficial temporal arteries. |
What is the anterior boundary of the temporal fossa? | Posterior surface of frontal process of zygomatic & zygomatic process of frontal bone. |
What is the superior and posterior boundary of the temporal fossa? | Superior & inferior temporal lines. |
What is the lateral boundary of the temporal fossa? | Temporal fascia. |
What is the inferior boundary of the temporal fossa? | Supramastoid crest of temporal bone. Infratemporal crest of greater wing of sphenoid. Zygomatic arch. |
What is the floor of the temporal fossa? What will you find the fossa? | The greater wing of the sphenoid, frontal, temporal, and parietal bones. The pterion will be sitting in there. |
Where does the temporalis muscle attach? | It attaches to periosteum of the temporal fossa and the temporal fascia, then runs down deep to zygomatic arch to attach to coronoid process & anterior ridge of mandibular ramus. |
Where is the temporalis muscle located? | In the temporal fossa. |
What does the temporalis muscle do? | Powerfully elevates jaw. And posterior fibers are powerful retractors. |
What is e blood supply to the temporalis muscle? | Deep temporal arteries, branches off maxillary artery (in infratemporal fossa) & middle temporal artery off superficial temporal juuuust above zygo arch. |
What is the temporalis muscle innervated by? | V3 in general. Anterior and posterior deep temporal arteries to be specific. |
What is parotidectomy? What is a possible risk? | Surgical removal of the parotid gland, usually b/c of a tumor. Can wind up damaging postgan parasympath fibers that regenerate in the wrong place, into sympath pathways, causing Frey's syndrome. |
What is TMD? | Temporomandibular joint disorder. Can be mainly either muscular or articular. Usually lateral pterygoid has increased tension on it. Or can be a dislocation of articular disc, it can be so bad that jaw can get stuck in open position (anterior dislocation) |
Why is posterior dislocation of TMJ so uncommon? | Postglenoid tubercle of temporal bone is in the way & lateral ligament of TMJ just doesn't go that way. |