L32 - Infratemporal Fossa & Parotid Gland Flashcards
Location of temporal fossa?
Narrow fan shaped space: interconnect spaces on lateral side of the head
Location of infratemporal fossa? (medial, anterior, posterior, boundaries)
Inferior of temporal fossa, under zygomatic arch, Between side wall of pharynx and mandibular ramus
medial to temporomandibular joint and muscles of mastication
Anterior = posterior surface of maxilla
Posterior = opens to neck
Describe the roof of the infratemporal fossa? List 3 major foramen/ fissures?
Infratemporal surface of greater wing of sphenoid and temporal bone,
Opens to temporal fossa lateral to the infratemporal crest
Contains the foramen ovale, foramen spinosum and petrotympnic fissure
Content bound by the foramen ovale? ‘OVALE’
Otic ganglion V3 Accessory meningeal artery Lesser petrosal nerve Emissary veins
Content bound by foramen spinosum?
Middle meningeal A/V
meningeal branch of mandibular nerve
Content that passes through petrotympnic fissure?
Chorda tympani of facial nerve
Describe the anterior wall of the infratemporal fossa + a major fissure on it?
Anterior wall
- Posterior surface of the maxilla, maxillary tuberosity
- Contains alveolar foramina
- Upper part opens as the inferior orbital fissure
Content of the inferior orbital fissure on the upper part of the anterior wall of infratemporal fossa?
Zygomatic branch of maxillary nerve
Infraorbital nerves
Pterygopalatine ganglia
Describe the medial wall of the infratemporal fossa + one major fissure on it?
Formed by:
- Lateral pterygoid plate (superiorly)
- Lateral wall of pharynx
- Tensor and levator veli palatini
Contains pterygomaxillary fissure
Describe the lateral wall of the infratemporal fossa + one major foramen?
Formed by medial surface/ inside of the mandibular ramus
Contains mandibular foramen
List the foramen/ fissures that connect infratemporal fossa with cranial cavity, orbit and pterygopalatine fossa?
To cranial cavity: Roof: F. ovale and F. spinosum
To orbit: upper Anterior wall: Inferior orbital fissure
To Pterygopalatine fossa: Medial wall: Pterygomaxillary fissure
List the 6 content of the infratemporal fossa? ML MS MP
Medial pterygoid muscle
Lateral pterygoid muscle
Maxillary artery
Sphenomandibular ligament
Mandibular nerve
Pterygoid venous plexus
Range of movement of the TMJ?
Temporomandibular joint
Opening and closing mouth, chewing
+ side to-side movement of lower jaw
Describe the joint in TMJ?
Formed between head of mandible + Mandibular fossa/ articular tubercule
Double joint: Upper and lower joint cavities divided by articular disc
How is the TMJ stabilized? (SLS)
Via 3 Extracapsular ligaments
- Sphenomandibular ligament (spine of sphenoid bone»_space; lingula of mandible)
- Lateral ligament
- Stylomandibular ligament
What regions does the stylomandibular ligament separate?
Separate parotid and infratemporal region
Origin, insertion and action of the medial pterygoid muscle (one content of the infratemporal fossa)?
Origin = 2 heads: Deep head (from Lateral pterygoid plate) + Superficial head (from maxillary tuberosity and pyramid of palatine)
Insertion: Medial Angle of Mandibular ramus (roughened lower area for attachment)
Action: Elevate, protrude and move mandible medially
Origin, insertion and action of Lateral pterygoid muscle?
Origin: Triangular with 2 heads: Upper (roof of infratemporal fossa, lateral to 2 foramen) and lower (lateral pterygoid plate, between 2 heads of medial pterygoid)
(buccal nerve passes through gap between 2 heads)
Insertion: condylar process of mandible
Action: Major protruder, side to side movement of lower jaw
What is lateral to the infratemporal fossa?
Muscles of mastication
TMJ
List the muscles of mastication and their innervation?
innervated by mandibular nerve (+maxillary nerve)
- Temporalis (superior)
- Masseter (lateral)
- Medial pterygoid (content of infratemporal fossa)
- Lateral pterygoid (content of infratemporal fossa)
List the muscles for protrusion of lower jaw?
Lateral pterygoid + medial pterygoid
List the muscles for retraction of lower jaw?
Temporalis (posterior fibers) + masseter + geniohyoid + diagastric
List the muscles for elevation of lower jaw?
Medial pterygoid muscle
+ masseter
+ Temporalis
List the muscles for depression of lower jaw?
Diagastric + geniohyoid + mylohyoid
assisted by gravity
Origin, insertion and action of temporalis muscle?
- Origin: bony surface superior to the inferior temporal line, lateral to temporal fascia
- Insertion: the coronoid process and anterior margin of ramus of mandible
-Actions:
anterior fibres elevate mandible and close jaw
posterior fibres retract mandible, assist side-to-side movement
Origin, insertion and action of Masseter?
Two heads: superficial and deep heads
- Origin: maxilla and zygomatic arch
- Insertion: lateral surface of ramus/angle of mandible and coronoid process
- Actions: elevation and protraction of mandible
Define the origin and tract of the motor and sensory division of mandibular nerve reaching infratemporal fossa?
Split into anterior, posterior and trunk branches
Sensory: originates from trigeminal ganglion, drops through foramen ovale
Motor: passes medially to the trigeminal ganglion to enter foramen ovale, fuses together to become mandibular nerve
List the trunk branches of the mandibular nerve in the infratemporal fossa?
1 -Meningeal nerve enters foramen spinosum (with middle meningeal artery); sensory to dura mater in the middle cranial fossa
2 -Nerve to medial pterygoid supplies medial pterygoid, branches to nerves to tensor tympani and tensor veli palatini
List the 4 anterior branches of the mandibular nerve in the infratemporal fossa?
3 motor, 1 sensory
- Masseteric nerve: motor, to masseter
- Deep temporal nerves: motor, to temporalis (upwards into temporal fossa)
- Nerve to lateral pterygoid: motor, to lateral pterygoid
- Buccal nerve: sensory, to cheek (skin, mucosa, buccal gingivae)
List the 3 posterior branches of the mandibular nerve in the infratemporal fossa?
Auriculotemporal nerve
Inferior alveolar nerve
Lingual nerve
Structures supplied by Auriculotemporal nerve
- sensory, to skin over temple, external ear, external acoustic meatus, tympanic membrane, TMJ
- carries postsynaptic parasympathetic secretomotor fibers of glossopharygeal nerve IX from otic ganglion to parotid gland
- two roots route around/envelop the middle meningeal artery
Structures supplied by Inferior alveolar nerve
- mostly sensory, to all lower teeth and much of associated gingivae, mucosa and skin of lower lip, skin of chin
- gives a motor branch to mylohyoid (for mylohyoid and ant. belly of digastric)
- terminates as incisive and mental nerve
Structures supplied by Lingual nerve
- sensory, to anterior 2/3 of the tongue, mucosa of oral cavity floor, lingual gingivae
- joined by chorda tympani (branch of facial nerve VII), provides special sensation (taste) to the anterior 2/3 part of the tongue
- pre/postsynaptic parasympathetic fibres to all salivary glands below the level of oral fissure
List the nerves that exist in the lower region of the infratemporal fossa? (upper region = mandibular nerve and branches)
Chorda tympani
Submandibular ganglion
Lesser petrosal nerve
Function and tract of chorda tympani passing through infratemporal fossa?
- Branch of facial nerve VII»_space; inside temple bone»_space; petrotympnic fissure»_space; lingual nerve
- Special sensory fibers for taste sensation from the anterior 2/3 of tongue
- Presynaptic parasympathetic fibers to submandibular ganglion»_space; two salivary glands + blood vessels of the tongue
Function and tract of submandibular ganglion in the infratemporal fossa?
- Connected to lingual nerve
- Carries secondary cell bodies for presynaptic fibres in chorda tympani
- Postsynaptic fibres travel along lingual nerve to sublingual and submandibular glands
Function and tract of lesser petrosal nerve in infratemporal fossa?
- Branch of tympanic plexus, carries presynaptic fibers from glossophayngealnerve IX
- Passes medially and descends with mandibular nerve through foramen ovale
- Presynaptic fibers synapse in otic ganglion
- Postsynaptic fibers join the auriculotemporal nerve
Origin and supply of Maxillary artery in the infratemporal fossa?
External carotid artery
Supplies nasal cavity, lateral wall + roof of oral cavity, all teeth, dura mater, infratemporal fossa…etc
Divide the maxillary artery into 3 parts regarding their location?
first part: between the neck of the mandible and sphenomandibular ligament
second part: related to lateral pterygoid muscle
third part: in the pterygopalatine fossa
Branches from 1st part of maxillary artery?
- middle meningeal artery
- inferior alveolar artery
- deep auricular, anterior tympanic and accessory meningeal arteries
Branches from 2nd part of maxillary artery?
-gives origin to deep temporal, masseteric, buccal, and pterygoid branches
Branches from 3rd part of maxillary artery?
- greater (descending) palatine artery
- posterior superior alveolar artery
- pharyngeal artery
- infraorbital artery
- artery of the pterygoid canal
- sphenopalatine artery
List the 6 structures supplied by the pterygoid plexus
nasal cavity, roof and lateral wall of oral cavity, all teeth, muscles in infratemporal fossa, paranasal sinuses nasopharynx
How does the pterygoid plexus connect with the cavernous sinus?
inferior ophthalmic vein, emissary veins that pass through the skull through the foramen Vesalii, foramen ovale, and foramen lacerum
List some anterior venous connections the pterygoid plexus makes?
- Inferior ophthalmic vein (from the orbit drains through inferior orbital fissure into the plexus)
- deep facial vein, connects with the facial vein
List some posterior venous connections the pterygoid plexus makes?
short maxillary vein, connects with the retromandibular vein
How can oral or nasal infections spread intracranially and cause septic thrombosis?
Danger triangle of face»_space; facial vein»_space; pterygoid plexus»_space; cavernous sinus
septic thrombosis (may leads to stroke, meningitis, or encephalitis)
Which structures are damaged in the fracture of pterion?
Pterion in temporal fossa overlie anterior branches of the middle meningeal vessels
> > rupture causes haematoma, lethal if untreated
Clinical sequalae if the lingual nerve is injured Proximal to where chorda tympani joins?
loss of general sensation at anterior 2/3 of the tongue, oral mucosa, gingivae
Clinical sequalae if the lingual nerve is injured distal to where chorda tympani joins?
loss of general sensation at anterior 2/3 of the tongue, oral mucosa, gingivae
+
loss of secretion from the salivary glands below the oral fissure
+
Loss of taste from the anterior 2/3 of the tongue
Describe the course of the lingual nerve in the oral cavity?
Enters oral cavity floor in a shallow groove on medial surface of mandible
immediately inferior to the last molar tooth
Where is general anesthesia inject to anesthetize inferior alveolar nerve, infraorbital, mental, incisive or buccal nerves?
lateral to the anterior arch of the fauces (palatoglossalarch) in the oral cavity
Location of parotid gland?
below the external acoustic meatus
Wedged between the ramus of the mandible, the sternocleidomastoidmuscle and the mastoid process
Parotid fascia = continuation of neck fascia
Which nerve divides the parotid gland into 2 parts?
Divided into two parts by facial nerve: superficial and deep parts
List the 3 structures that traverse the parotid gland, from deep to superficial?
deep to superficial
- External carotid artery
- Retromandibular vein
- Facial nerve and its branches
Describe the tract of facial nerve after it bifurcates at the parotid gland?
-The upper division: temporal and zygomatic branches
-The lower division:
buccal, marginal mandibular, and cervical branches
Describe the tract of the facial nerve before it enters the parotid gland?
emerges from the stylomastoid foramen,
winds laterally to the styloid process
dives into the posteromedial surface of the parotid gland
Where does the parotid duct open into the oral cavity?
arises from the anterior border (On masseter about one finger’s breadth below the zygomatic arch)
-Opens into the mucosa opposite the second upper molar teeth at the parotid papilla
