Deep Face, Infratemporal Region, and TMJ

Question 1

• space superior to the zygomatic arch:
• space inferior to the zygomatic arch:

Answer 1

• temporal fossa
• infratemporal fossa

Question 2

What are the boundaries of the infratemporal fossa?

Answer 2

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

Question 3

What are the contents of the infratemporal fossa?

Answer 3

• inferior portion of temporalis M.
• lateral and medial pterygoid Ms.
• maxillary A.
• pterygoid venous plexus
• nervous structures: inferior alveolar N. (V3), lingual N. (V3), buccal N. (V3), chorda tympani (CN VII), otic ganglion

Question 4

The maxillary A. is broken up into 3 parts, what are the branches off each part?

Answer 4

(maxillary A. is a branch off the ECA)

• 1st part
  
  • deep auricular A.
  • anterior tympanic A.
  • mylohyoid A.
  • inferior alveolar A. (lingual foramen of the mandible) > mental A. (mental foramen) > incisive A.
  • middle meningeal A. > (foramen spinosum) > anterior branch of middle meningeal A. and posterior branch of middle meningeal A.
  • accessory meningeal A. (foramen ovale)
• 2nd part
  
  • posterior deep temporal A.
  • medial pterygoid A.
  • lateral pterygoid A.
  • masseteric A.
  • buccal A.
  • anterior deep temporal A.
• 3rd part
  
  • posterior superior alveolar A.
  • descending palatine A.
  • infraorbital A. > anterior superior alveolar A. branches > infraorbital A. (infraorbital foramen)
  • pharyngeal A.
  • artery of pterygoid canal
  • sphenopalatine A.

Question 5

What is the somatic sensory and somatic motor innervation of the mandibular division (CN V3) of the trigeminal N.?

Answer 5

• somatic sensory
  
  • buccal
  • lingual
  • inferior alveolar: dental, incisive, mental
  • auriculotemporal: anterior auricular, external acoustic meatus, temporomandibular joint, superficial temporal
• somatic motor
  
  • medial pterygoid: tensor veli palatini, tensor tympani
  • lateral pterygoid
  • masseteric
  • deep temporal
  • mylohyoid: nerve to mylohyoid, nerve to anterior belly of digastric

Question 6

What is the somatic sensory innervation of the maxillary division (V2) of the trigeminal N.?

Answer 6

• somatic sensory
  
  • zygomatic: zygomaticotemporal, zygomaticofacial (communicating branch to lacrimal N. (V1)
  • infraorbital: external nasal, superior labial
  • superior alveolar: anterior, middle, posterior
  • palatine: orbital, greater and lesser palatine, posterior superior nasal, pharyngeal
  • meningeal: anterior cranial fossa, middle cranial fossa

Question 7

What are the variants in the maxillary A. in relation to the lateral pterygoid M.?

Answer 7

a) can run lateral to lateral pterygoid (easier to accidently cut when removing ramus of mandible)
b) can run medial to lateral pterygoid (most common variant, more protected)

Question 8

What are the muscles of mastication and their innervation?

Answer 8

• innervation by trigeminal N. (CN V3)
• four paired muscles: temporalis, masseter, lateral pterygoid, and medial pterygoid

Question 9

masseter M.

• origin:
• insertion:
• action:
• innervation:

Answer 9

masseter M.

• origin: superficial head (zygomatic bone (maxillary process) and lateral aspect of anterior 2/3 of zygomatic arch), middle head (medial aspect of anterior 2/3 of zygomatic arch), deep head (deep surface of posterior 1/3 of zygomatic arch)
• insertion: superficial head (inferior lateral surface of mandibular angle and ramus), middle head (central part of occlusal surface of mandibular ramus), deep head (superior lateral surface of mandibular ramus and inferior coronoid process)
• action: elevates mandible, assists in protraction, retraction, and side to side motion
• innervation: masseteric N. (anterior division of CN V3)

Question 10

temporalis M.

• origin:
• insertion:
• action:
• innervation:

Answer 10

temporalis M.

• origin: superficial head (temporal fascia), deep head (inferior temporal line of temporal fossa)
• insertion: coronoid process of mandible (apex, medial surface, and anterior surface of mandibular ramus)
• action: vertical (anterior) fibers (elevate mandible), horizontal (posterior) fibers (retract mandible), unilateral (lateral movement of mandible, chewing)
• innervation: deep temporal N. (anterior division of CN V3)

Question 11

lateral pterygoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 11

lateral pterygoid M.

• origin: superior head (infratemporal crest of greater wing of sphenoid bone), inferior head (lateral surface of lateral pterygoid plate)
• insertion: superior head (pterygoid fovea of mandible and articular disk of TMJ), inferior head (pterygoid fovea and condylar process of mandible)
• action: bilateral (protrudes mandible and opens mouth), unilateral (alternating actions, along w/ ipsilateral medial pterygoid, result in side to side movements necessary for grinding)
• innervation: lateral pterygoid nerve (anterior division of CN V3)

Question 12

medial pterygoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 12

medial pterygoid M.

• origin: superficial head (maxillary tuberosity of maxilla and pyramidal process of palatine bone), deep head (medial surface of lateral pterygoid plate and pterygoid fossa)
• insertion: pterygoid rugosity on medial surface of mandibular angle
• action: bilateral (elevation of mandible, acts w/ lateral pterygoid to assist in protrusion of mandible), unilateral (acts w/ ipsilateral lateral pterygoid to protrude mandible and produce medial movement toward the opposite side, alternating actions between right and left sides results in side to side chewing)
• innervation: medial pterygoid N. (anterior division of CN V3)

Question 13

digastric M.

• origin:
• insertion:
• action:
• innervation:

Answer 13

digastric M.

• origin: anterior belly (digastric fossa of the mandible), posterior belly (medial to the mastoid notch of the mastoid process)
• insertion: body of the hyoid bone via an intermediate tendon w/ fibrous loop
• action: elevates the hyoid bone (during swallowing), assists in opening the mandible
• innervation: anterior belly (nerve to the mylohyoid M. from the mandibular nerve of CN V), posterior belly (facial N., CN VII)

Question 14

geniohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 14

geniohyoid M.

• origin: inferior mental spine of the mandible
• insertion: body of the hyoid bone
• action: draws the hyoid bone forward (during swallowing), assists in opening the mandible
• innervation: ventral ramus of C1

Question 15

mylohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 15

mylohyoid M.

• origin: mylohyoid line of the mandible
• insertion: body of the hyoid by a median tendon of insertion (mylohyoid raphe)
• action: tightens and elevates oral floor, draws the hyoid bone forward (during swallowing), assists in opening the mandible and moving it from side to side (mastication)
• innervation: mylohyoid N. (from mandibular N. division of CN V)

Question 16

stylohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 16

stylohyoid M.

• origin: styloid process of temporal bone
• insertion: body of hyoid bone by a split tendon
• action: elevates hyoid bone (swallowing), assists in opening the mandible
• innervation: facial N. (CN VII)

Question 17

sternohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 17

sternohyoid M.

• origin: posterior surface of the manubrium of the sternum and sternoclavicular joint
• insertion: body of the hyoid bone
• action: depresses (fixes) hyoid bone, depresses larynx and hyoid bone (for phonation and terminal phase of swallowing)
• innervation: ansa cervicalis of cervical plexus (C1-3) and C4

*1 in photo*

Question 18

sternothyroid M.

• origin:
• insertion:
• action:
• innervation:

Answer 18

sternothyroid M.

• origin: posterior surface of the manubrium of sternum
• insertion: oblique line of the thyroid
• action: draws the larynx and hyoid bone downward (fixes hyoid), depresses larynx and hyoid bone (phonation and terminal phase of swallowing)
• innervation: ansa cervicalis of cervical plexus (C1-3) and C4

*2 in picture*

Question 19

thyrohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 19

thyrohyoid M.

• origin: oblique line of the thyroid
• insertion: body of the hyoid bone
• action: depresses and fixes hyoid bone, raises larynx during swallowing
• innervation: ventral ramus of C1 and C4

*3 in picture*

Question 20

omohyoid M.

• origin:
• insertion:
• action:
• innervation:

Answer 20

omohyoid M.

• origin: superior border of scapula
• insertion: body of hyoid bone
• action: depresses (fixes) hyoid bone, draws larynx and hyoid bone downward (phonation and terminal phase of swallowing), tenses cervical fascia w/ its intermediate tendon and maintains patency of internal jugular V.
• innervation: ansa cervicalis of cervical plexus (C1-3) and C4

Question 21

What muscles produce these movements of the mandible:

• elevation:
• depression:
• protrusion:
• retrusion:
• lateral movements:

Answer 21

• elevation: temporalis, masseter, medial pterygoids
• depression: lateral pterygoids, suprahyoid and infrahyoid
• protrusion: lateral pterygoids, masseter, medial pterygoids
• retrusion: temporalis, masseter
• lateral movements: ipsilateral temporal and masseter + contralateral pterygoids

Question 22

What are the ligaments present within the TMJ?

Answer 22

• lateral ligament
• stylomandibular ligament (limits inferior excursion at TMJ)
• sphenomandibular ligament (limits inferior excursion at TMJ)

Question 23

What nerves are in close proximity to the TMJ?

Answer 23

• facial N.
• auriculotemporal N. (not labeled in photo but mentioned in lecture)

Question 24

What is the relationship between the lateral pterygoids and the TMJ?

Answer 24

• upper part of the inferior head and all of the superior head of lateral pterygoid attaches to the articular disc of the TMJ
• when contracted, these muscles pull the articular disc out onto the articular tubercle and pulls the head of the mandible anteriorly for a full opening (gape) of the mouth

Question 25

Describe the positional sift in structures of the TMJ with opening and closing of the mouth:

Answer 25

- jaw opening \<15 degrees: hinged swinging in neutral position of articular disc and head of mandible - jaw opening \>15 degrees: articular disc pops out onto articular eminence and "pesudo dislocates" the jaw

Question 26

What nerves innervate the TMJ?

Answer 26

\*all nerves are derived from **mandibular N. (CN V3)** of the trigeminal N.\* - anterior division: posterior deep temporal N. and masseteric N. - posterior division: auriculotemporal N.

Question 27

What happens during anterior dislocation of the TMJ?

Answer 27

- the head of the mandible pops all the way off the articular tubercle (eminence) anteriorly - tx: reset the head of the mandible into the mandibular fossa

Question 28

What nerve block provides local anesthetic to the lower half of dentition?

Answer 28

inferior alveolar nerve block

Question 29

Where would you receive injections to anesthesize anterior teeth?

Answer 29

injections at 2nd molar, 1st molar, and 2nd premolar near infraorbital foramen (anterior (infraorbital) superior alveolar nerve block)

Question 30

a depression on the temporal regionm one of the largest landmarks on the skull - borders: temporal bone, sphenoid bone, parietal bone and frontal bone contribute to its concave wall - it is superior to the infratemporal fossawhich lies beneath the zygomatic arch

Answer 30

temporal fossa

Question 31

- paired fossa of the skull - roof: greater wing of sphenoid - anterior: maxilla - posterolateral: pterygoid process of sphenoid - medial: vertical plate of palatine bone - floor: horizontal plate of palatine bone

Answer 31

pterygopalatine fossa

Question 32

List the sphenoid bone foramen and structures:

Answer 32

- **lesser wings**: superolateral, form the optic canal (optic N. and opththalmic A.) - **greater wings**: posterolateral - **foramen rotundum**: maxillary N. - **foramen ovale**: MALE mnemonic (mandibular N., accessory meningeal A., lesser petrosal N., emissary V.) - **foramen spinosum**: middle meningeal vessels, meningeal branch of mandibular N. - **superior orbital fissure**: superior ophthalmic V., ophthalmic N. and its branches, abducent N., oculomotor N., trochlear N. - **pterygoid processes**: ptreygoid canal (major and deep petrosal Ns.), pharyngeal canal (pharyngeal N.)