Lecture 5 = Parotid & Temporal Regions and TMJ Flashcards
Where is the parotid gland and what runs through it?
- it is located inferior to the ear
- it contains the retromandibular v., external carotid a., and the facial nerve.
- parotid has a dense CT fascia that completely surrounds the gland and is continuous with the investing fascia
- the fascia isn’t elastic so any swelling has the potential to block the secretory unit and any one of these structures in or around the gland
- the gland is well innervates so any blockage can be painful
What is the relationship of the parotid to the ear?
- gland is just (directly anterior) inferior to the external acoustic meatus
- swelling of gland will push ear superolateral like in mumps
- swelling of gland can come onto the TMJ too
- but only the soft tissue elements are moved and they can be displaced away from the bony elements
What is the retromandibular gland formed by?
- its formed by superficial temporal and maxillary vv. - come together to drain into retromandibular v.
- enters parotid posterior to ramus of mandible
- splits into 2 divisions that drain into the (posterior division) EJV and (anterior division) IJV
What is the external carotid artery?
- distal portion lies deep within parotid gland
- parallels retromandibular v. just deep to it
- posterior to mandibular neck, splits to 2 terminal branches
- superficial temporal a.
- maxillary a.
What is deep to the parotid bed?
- the carotid sheath which is contains the internal carotid artery, the internal jugular vein, and the vagus nerve
- in the parotid bed, see branches of CN VII run through posterior belly of digastric and styloid process and stylohyoid mm.
Where does the facial nerve exit form and what does it form?
-exits cranium via stylomastoid foramen
-forms parotid plexus within gland
-branches emerge and fan out over lateral aspect of face
-innervate all mm. of facial expression
it’s sensory ganglion = the geniculate ganglion, lies within the temporal bone
What are the branches of the facial n.?
-temporal branches
-zygomatic branches
-temporofacial branch
-posterior auricular nerve
-cervicofacial branch
-buccal branches of VII innervates the buccinator mm b/c facial n. innvervates MUSCLE of facial expression
-marginal mandibular branches
-cervical branches - innervates platysma
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Where are the fossas and spaces continuous with each other?
- they are continuous with each other in the temporal region
- the submassteric space is continuous with the deep infratempral fossa
- in the temporal fossa, the line of demarkation between the bones of the neurocranium and bones of viscerocranium is the zygomatic arch.
What are the contents temporal fossa?
-temporal fat pad
*enclosed in temporal fascia and fills out temple region
* between temporalis m. and lateral wall of orbit
* temporal mm. attaches on the coronoid process
-muscles
* temporalis m. - covered by thick temporal fascia
masseter m. - works with temporalis m. to elevate mandible ( not content of temporal fossa but works with the content)
~ A: elevate mandible (close mouth)
~ N: masseteric branch of V3
- neurovasculature - find this on the deep surface b/c it’s the most protected there
* middle temporal artery
* deep temporal artery
* superficial temporal artery
What are the parts of the maxillary artery?
- mandibular a.
- pterygoid a.
- pterygopalatine a.
What are the branches of the trigeminal n. mandibular division (Cn V3)?
Auriculotemporal nerve
- travels with superficial temporal a. and v.
- runs deep to parotid gland and posterior to TMJ
* between the auricle and condyle of mandible
- provides sensory innervation to TMJ and lateral scalp
- carries p-sympathetics fibers from CN IX into parotid gland (autonomics often hitch a ride with V1, V2, and V3 to get to places they need to be at)
Ant. and Post. deep temporal nn.
- passes superior to lateral pterygoid m. and deep to temporalis m.
Temporalis branches of facial n. (CN VII)
What are the borders of the infratemporal fossa?
-lateral border: ramus the mandible and coronoid process of the mandible
-medial border: lateral pterygoid plate of the sphenoid, the superior constrictor m. and the pyramidal process of the palatine bone
-superior border: infratemporal surface of the greater wing of the sphenoid with the foramen oval and foramen spinosum
-anterior - posterior portion of the maxilla
-posterior - tympanic plate, mastoid, and styloid processes
-inferior border - no anatomic floor, fossa ends where the medial pterygoid attaches to the mandible
The roof:
- the inferior surface of the greater wing of the sphenoid; temporal bone, the foramen ovale and the foramen spinosum
What are the contents of the infra temporal fossa?
Muscles:
- temporalis, medial and lateral pterygoids mm., no masseter because it’s on the outside
A and V:
- maxillary and branches of pterygoid plexus of veins
Nerves:
- mandibular division of CN V (V3)
- posterior superior alveolar n. (V2)
- chorda tympani n. branch of CN VII (facial)
- otic ganglion
- lesser petrosal n.
What are the actions of the pterygoid mm?
- medial pterygoid m.: elevates, protrudes, and rotates mandible
- lateral pterygoid m.: opens, protrudes and rotates mandible
What is the trigeminal n. Mandibular branch V3 and what are it’s divisions?
- has a large sensory root and a small motor root (serves mm of mastication)
- they unite after passing through foramen ovale to enter infratemporal fossa
- meningeal branch n (immediately off of V3 and has a recurrent meningeal branch)
-medial pterygoid, tensor tympani (ear - near tympanic membrane - acts on one of the ossicles to increase the tension on tympanic membrane) and tensor veil palatini nn - divides into anterior and posterior divisions
- Ant: small, mainly motor
~has 1 sensory branch = (buccal n of V3) - Post: larger, mainly sensory
~ has 1 motor branch = (mylohyoid n.)
- Ant: small, mainly motor
- V1, V2, V3 all have recurrent meningeal branch off of them that supplies dura.
