8. Infratemporal Fossa and Temporomandibular Joint

Question 1

What does the temporal region contain?

Answer 1

temporal and infratemporal fossae

Question 2

Where are the (1) temporal fossa and (2) infratemporal fossa found?

Answer 2

1. superior to to zygomatic arch
2. inferior to the zygomatic arch

Question 3

bones of the infratemporal fossa

Answer 3

Question 4

boundaries of the infratemporal fossa

Answer 4

• lateral = ramus of mandible
• anterior = maxilla
• medial = lateral pterygoid plate
• roof = sphenoid (greater wing)
• posterior = tympanic plate & mastoid and styloid process
• inferior = angle of mandible

Question 5

contents of the infratemporal fossa

Answer 5

Question 6

supplies external acoustic meatus, external tympanic membrane, and TMJ

Answer 6

deep auricular artery

Question 7

supplies internal TM

Answer 7

anterior tympanic artery

Question 8

enters madibular foramen and supplies mandible, mandibular teeth, chin, and mylohyoid m.

Answer 8

branches of inferior alveolar a.

[mylohyoid artery and mental artery]

Question 9

enters cranium via foramen spinosum and supplies dura mater of lateral wlal, trigeminal ganglion, facial nerve, and geniculate ganglion, tympanic caity, and tensory tympani m.

Answer 9

middle meningeal artery

Question 10

enters cranium via foramen ovale and supplies extracranial muscles of infratempora fossa, otic ganglion, and sphenoid bone

Answer 10

accessory meningeal artery

Question 11

supplies temporalis m.

Answer 11

deep temporal artery

Question 12

supplies pterygoid m.

Answer 12

pterygoid branches of maxillary artery

Question 13

supplies TMJ and masseter muscle

Answer 13

masseteric artery

Question 14

supplies bucca fat-pad, buccinator, and buccal oral mucosa

Answer 14

buccal artery

Question 15

arteries from the mandibular part of the maxillary artery

Answer 15

• deep auricular artery
• anterior tympanic artery
• inferior alveolar artery
• middle meningeal artery
• accessory meningeal artery

Question 16

arteries from the pterygoid part of the maxillary artery

Answer 16

• deep temporal artery
• pterygoid branches
• masseteric artery
• buccal artery

Question 17

What nerve does the buccal artery run with?

Answer 17

buccal nerve

Question 18

branches of mandibular division of trigeminal nerve (V3)

Answer 18

Question 19

branches of maxillary division of trigeminal n. (V2)

Answer 19

Question 20

Infratemporal fossa: relational anatomy

Answer 20

Question 21

Infratemporal fossa: relational neurology

Answer 21

Question 22

Fracture at the neck of the mandible can damage what structures?

Answer 22

V3 and otic ganglion

Question 23

Fracture at the ramus of the mandible can damage what structures?

Answer 23

inferior alveolar vessels/artery

Question 24

Fracture at the corpus can damage what structures?

Answer 24

inferior alveolar vessels/arteries

Question 25

variations in location of the **maxillary artery** in relation to other structures

Answer 25

* in relation to lateral pterygoid m. * max a. can run lateral to muscle * max a. can run medial to muscle * in relation to nerves * medial to buccal nerve (but lateral to lingual n. & inferior alveolar n.) * medial to buccal and lingual n. (lateral to inferior alveolar n.) * medial to mandibular n. (V3)

Question 26

muscles of mastication & innervation

Answer 26

* temporalis m. * masseter m. * lateral pterygoid m. * medial pterygoid m [innervated by trigeminal n.]

Question 27

muscles of mastication involved in movement at what joint?

Answer 27

TMJ

Question 28

temporalis m. (superficial head)

Answer 28

* origin: temporal fascia * insertion: cornoid process of mandible * innervation: deep temporal n. (CN V3) * action: * vertical fibers: elevate mandible * horizontal: retract mandle * unilateral: lateral movement of mandible

Question 29

temporalis m. (deep head)

Answer 29

* origin: temporal fossa * insertion: cornoid process of mandible * innervation: deep temporal n. (CN V3) * action: * vertical fibers: elevate mandible * horizontal: retract mandle * unilateral: lateral movement of mandible

Question 30

lateral pterygoid (superior/upper head)

Answer 30

* origin: greater wing of sphenoid bone * insertion: mandible * innervation: lateral pterygoid n. * action: * bilateral: protrudes mandible and opens mouth * unilateral: alternating actions, along with ipsilateral medial pterygoid; side-to-side movement necessary for grinding

Question 31

lateral pterygoid (inferior/lower head)

Answer 31

* origin: lateral pterygoid plate * insertion: mandible * innervation: lateral pterygoid n. * action: * bilateral: protrudes mandible and opens mouth * unilateral: alternating actions, along with ipsilateral medial pterygoid; side-to-side movement necessary for grinding

Question 32

What opens the mandible?

Answer 32

Question 33

elevation of the mandible

Answer 33

* temporalis m. * masseter m. * medial pterygoids m.

Question 34

depression of the mandible

Answer 34

* lateral pterygoids m. * suprahyoid m. * infrahyoid mm.

Question 35

protrusion of the mandible

Answer 35

* lateral pterygoids * masseter m. * medial pterygoids

Question 36

retrusion of the mandible

Answer 36

* temporalis m. * masseter m.

Question 37

lateral movements of the mandible

Answer 37

* ipsilateral temporalis m. and masseter m. * contralateral pterygoids

Question 38

What nerve runs close to the TMJ capsule?

Answer 38

facial n.

Question 39

jaw dislocation

Answer 39

excessive contraction of the *lateral pterygoids* may cause heads of mandible to dislocate anteriorly (anterior to articular tubercles) appearance: mandible depressed & person unabe to close his/her mouth \*close proximity: facial nerve and auriculotemporal nerve [if damage to auriculotemporal nerve, laxity and instability of the TMJ]

Question 40

innervation of TMJ

Answer 40

Question 41

medial pterygoid (superficial/external head)

Answer 41

* origin: maxilla and palatine bone * insertion pterygoid rugosity on medial surface of mandibular angle * innervation: medial pterygoid n. * action: see below

Question 42

medial pterygoid m. (deep/internal head)

Answer 42

* origin: medial surface of lateral pterygoid plate and pterygoid fossa * insertion: pterygoid rugosity on medial surface of mandibualr angle * innervation: medial pterygoid n. * action: see below

Question 43

mandibular nerve block

Answer 43

inject near the mandibular nerve (infratemporal fossa) anesthesize: CN branches - auriculotemporal n., inferior alveolar n., lingual n., buccal * alternative*: pass needle through mandibular nothc of the ramus of the mandible into infratemporal fossa

Question 44

inferior alveolar nerve block

Answer 44

inject around mandibular foramen (opening into mandibular canal) anesthesizes inferior alveolar n. (CN V3) \*also anesthesize:; all mandibular teeth to the median plane, skin and mucus membrane of lower lip labial alveolar mucosa and gingiva, chin (mental n.)

Question 45

possible problem with inferior alveolar nerve block

Answer 45

injection of anesthetic into *parotid gland* or *medial pterygoid muscle* causes inability to open mouth (pterygoid trismus)