Anatomy: Infratemporal Fossa

Question 1

boundaries of temporal fossa?

Answer 1

ant/sup/post: superior temporal line
inferior/lat: zygomatic arch
infer/med: infratemporal crest of temporal and sphenoid bones

contents: upperio portion of temporalis mm. and dens temporalis fascia

Question 2

boundaries of infratemporal fossa?

Answer 2

lat: ramus of mandible
sup/lat: zygomatic arch
sup/med: lat pterygoid plate of sphenoid and pharynx
ant: maxilla
post: a line from ramus to mandible

Question 3

what does TMJ articulate b/w?

Answer 3

mandible-condyle
temporal bone- mandibular fossa and articular tubercle
- operates during chewing, while opening mouth the condyle of the mandible slides anteriorly against posterior surface of the articular tubercle.
- dense CT articular disk seperates the joint into two seperate synovial lined cavities
- joint cavity is loose above disc and tight below disc

Question 4

which ligament prevents post. dislocation of mandible?

Answer 4

lateral ligament of TMJ

- thickinging of joint capsule

Question 5

weak ligament of TMJ?

Answer 5

stylomandibular joint

- thickening of parotid fascia

Question 6

strongest ligament of TMJ? provides passive support?

Answer 6

sphenomandibular ligament

Question 7

what are components of TMJ joint?

Answer 7

upper portion: b/w temporal bone and disc = gliding mvmt, allows for protrusion/retrucion and elev/depression of mandible

lower portion (between disc and mandible)

• pivot mvmts.
• allows for side to side mvmt during chewing

Question 8

dislocation of TMJ? what could it damage?

Answer 8

mandibular condyle slides too far anteriorly (anterior to the articular tubercle) = inability to close jaw
* may damage the auriculotemporal nerve*

Question 9

arthritis of TMJ

Answer 9

heard in crepitus and popping while opening

Question 10

where are mm. of mastication derived from and innervated via?

Answer 10

1st pharyngeal arch. innervated by V3

Question 11

temporalis mm.

Answer 11

fn: elevates and retracts jaw
nn: V3 via anterior and posterior deep temporal nn.

• special feature* temporobuccinator band = dense CT that spans from temporalis tendon to buccinator mm, fn. is to pull buccinator m. away from teeth while chewing.

Question 12

masseter

Answer 12

fn: elevates and closes mandible, assists with protrusion
nn: V3 via masseteric branches

Question 13

medial pterygoid m.

Answer 13

inserts on internal surface of mandible! seen more inferiorly than lateral

fn: elevates, closes mandible.
nn: V3 via medial pterygoid branch

Question 14

lateral pterygoid

Answer 14

seen more superiorly and looks like attaches to TMJ. (stabalizes TMJ by attaching to the disc)

fn: protrusion of mandible, acting unilat. moves jaw towards contra. side to produce pivot (side-to-side) mvmt of chewing.
nn: lateral pterygoid branch of V3

Question 15

where do you see maxillary a? 3 portions?

Answer 15

courses posterior to neck of mandible (b/w mandible and sphenomandibular lig.)

1. mandibular
2. pterygoid
3. pterygopalatine

Question 16

five branches of mandibular portion of maxillary a?

Answer 16

courses deep to neck of mandible

1. deep auricular: external acoustic meatus and TMJ
2. ant. tympanic a: inner tymp. membrane (courses through pterotympanic fissure to reach middle ear)
3. middle meningeal a. - enters cranium via foramen spinosum to supply skull
4. accessory meningeal- enters via forament ovale to supply skull
5. inferior alveolar a: enters mandibular foramen to supply mandible, mandibular teeth and chin via a mental branch. also gives rise to mylohyoid a prior to entering mandibular foramen

Question 17

what are pterygoid branches?

Answer 17

courses either superficial or deep to lateral pterygoid m.

• masseteric
• anterior/post deep temporal
• medial pterygoid
• lat pterygoid branches
• buccal a: supplies cheek

Question 18

what are pterygopalatine portions?

Answer 18

• goes through pterygomaxillary fissure to enter pterygoplatatine fossa
• post. superior alveolar a.
• infraorbital a.
  pharyngeal a.
• a. of pterygoid canal
• descending palatine a.
• sphenopalatine a.

Question 19

where does pterygoid plexus communicate with?

Answer 19

receives blood from infratemporal fossa, nasal cavity, face via deep facial v, cavernous sinus via emissary vv, pharynx via pharyngeal vv.

• coalesces to form maxillary v. which then exits the infratemporal fossa traveling with the maxillary a.

Question 20

what components does V3 carry? where is it located?

Answer 20

• exits the middle cranial fossa via foramen ovale to enter infratemporal fossa
• components: GSA to lower portion of face, SVE to all mm. of 1st pharyngeal arch (masticaion, tensor tympani, tensor veli palatine, ant belly of digastric, mylohyoid)
• distributes GVE-P fibers from CN VII and CN IX to salivary glands
• distributes SVA fibers from the CN VII to the anterior 2/3 of tongue

Question 21

what are the sensory components of V3?

Answer 21

GSA

1. meningeal branch
2. Buccal n.
3. Lingual n.
4. Auriculotemporal n.

Question 22

What does meningeal branch supply?

Answer 22

• re-enters middle cranial fossa via foramen spinosum

- supplies GSA to dura of middle cranial fossa

Question 23

what does buccal n. supply?

Answer 23

exits infratemporal region by passing between the two heads of the lateral pterygoid mm.
- pierces mucosa of cheek to supply cheek and gingivae with GSA

Question 24

what does lingual n. supply?

Answer 24

exits the infratemporal region by passing b/w the medial and lateral pterygoid mm. and travels to the oral cavity.

• supplies the anterior 2/3rds of the tongue, floor of oral cavity and gingivae with sensory innervation via GSA
• Corda Tympani joins lingual n. in infratemporal fossa to distribute SVA fibers to anterior 2/3 of tongue.

Question 25

chorda tympani

Answer 25

comes from CN VII: taste and PS - joins the lingual n. in the infratemporal fossa to distribute taste (SVA) to the anterior 2/3rds of the tongue - also distributes GVE-P fibers to the submandibular and subligual glands

Question 26

auriculotemporal n.

Answer 26

- arises from two roots which make a ring around the middle meningeal a. - exits infratemporal fossa posteriorly by passing deep to neck ofmandible - provides GSA to the TMJ, temporal region, auricle, external acoustic meatus.

Question 27

motor branches of V3

Answer 27

1. medial pterygoid 2. n. to tensor tympani 3. n. to tensor veli palatini 4. lateral pterygoid nn. 5. massateric nn. 6. ant/posterior deep temporal nn.

Question 28

inferior alveolar n.

Answer 28

GSA and SVE branches of V3 - enters the mandibular foramen to supply the mandibular teeth - branches: 1. mental: exits the mental foramen to supply the chin 2. mylohyoid: SVE - supplies mylohyoid, anterior belly of digastric

Question 29

mandibular nerve block? inferior alveolar nerve block?

Answer 29

needle passed through mandibular notch to inject anesthetic around main trunk of mandibular teeth inferior alveolar nerve block: used primarily by dentists to anesthetize mandibular teeth, injected near entrance of mandibular foramen

Question 30

what supplies salivary glands?

Answer 30

the mandibular nerve supplies GVE-P to all salivary glands 1. auriculotemporal branch: distributes GVE-P fibers from CN IX (via lesser petrosal) to parotid gland 2. lingual brahnch: distributes GVE-P fibers from CN VII via corda tympani, to the submandibular and sublingual glands.

Question 31

what is PS innervation to parotid glands?

Answer 31

- distributed via the mandibular n. (V3) 1. pre cell bodies: salivatory nucleus in brainstem 2. pre cell fibers: travel with CN IX; via tympanic and lesser petrosal n. 3. post cell bodies: otic ganglion 4. post cell bodies distribute with the auriculotemporal branch of V3

Question 32

Otic ganglion

Answer 32

located in infratemporal fossa - suspended from V3, lies deep (medial) to main trunk of V3 - provides innervation to the parotid gland

Question 33

xerostomia

Answer 33

decreased PS innervation to parotid can lead to dry mouth

Question 34

PS innervation to submandibular and sublingual glands?

Answer 34

1. pre cell bodies: salivatory nucleus in brainstem 2. pre cell fibers: travel with CN VII via corda tympani 3. post cell bodies: submandibular ganglion 4. post cell fibers distribute with the lingual branch of V3

Question 35

pathway of PS preganglionic cell fibers that supply the sublingual and submandibular glands?

Answer 35

- pre cell bodies are located in salivatory nucleus within brainstem, and travel with CN VII. - CN VII courses along the posterior wall of the middle ear and gives rise to chorda tympani n. which exits the middle ear through the petrotympanic fissure to enter the infratemporal fossa. - here corda tympani joins the lingual n. - corda tympani portion of the lingual n. synapses in the submandibular ganglion.