Anatomy of mastication

Question 1

What does the occipitofrontalis do?

Answer 1

Elevates the eyebrows/wrinkles the forehead (the surprise muscle)

Question 2

What does the orbicularis occuli do?

Answer 2

Close the eyelids (the wink muscle)

Question 3

What does the Levator labii superioris do?

Answer 3

Elevates the upper lip and flares the nostrils

Question 4

What do the zygomaticus major and minor do?

Answer 4

Elevate the upper lip (the smile muscles)

Question 5

What does the orbicularis oris do?

Answer 5

Closes the lips/mouth

Question 6

What does the depressor anguli oris do?

Answer 6

Depress the lower lip

Question 7

What does the mentalis do?

Answer 7

Protrudes the lower lip (the pout muscle)

Question 8

What does the buccinator do?

Answer 8

Keeps the cheeks in contact with the gums so that food does not accumulate in the vestibule of the mouth.

Question 9

What muscles does the facial nerve (CN VII) innervate?

Answer 9

Pharyngeal arch two muscles i.e the muscles of facial expression and PSS (posterior belly of the digastric, stylohyoid, and stapedius).

Question 10

What are the main branches of the facial nerve?

Answer 10

Temporal branches, zygomatic branches, buccal branches, marginal mandibular branches, and cervical branches. “Ten Zebras Bit My Camel”

Question 11

Where does the facial nerve exit the skull to enter the face?

Answer 11

The stylomastoid foramen (only SVE in this part of the nerve).

Question 12

What is the arterial supply to the facial structures?

Answer 12

The facial artery, the superficial temporal artery, the maxillary artery, and the ophthalmic artery (all branches of the external carotid except the ophthalmic).

Question 13

What is the venous drainage of the face?

Answer 13

The retromandibular vein and the facial vein.

Question 14

What forms the retromandibular vein?

Answer 14

The superficial temporal and maxillary veins.

Question 15

What does the facial vein join with?

Answer 15

The anterior division of the retromandibular vein. This forms the common facial vein which then drains into the internal jugular vein.

Question 16

What are the deeper venous plexuses that communicate with the face?

Answer 16

The pterygoid plexus via the deep facial vein and the cavernous sinus via the ophthalmic veins.

Question 17

What is the significance of the deeper venous plexuses?

Answer 17

The make the central face a “danger area” for an infection to travel into the skull or deep face.

Question 18

What defines the parotid region?

Answer 18

It lies on the posterolateral side of the face; overlying the ramus of the mandible.

Question 19

What are the three structures that course through the parotid tissue?

Answer 19

The facial nerve, the retromandibular vein, and the external carotid artery.

Question 20

What defines the temporal fossa?

Answer 20

It is the lateral skull overlying the squamous portions of the frontal, parietal, temporal, and sphenoid bones.

Question 21

What are the major contents of the temporal fossa?

Answer 21

The upper portion of the temporalis muscle and the temporalis fascia.

Question 22

What defines the infratemporal fossa?

Answer 22

The deep region of the head lying inferior and deep (inferior-medial) to the temporal region.

Question 23

What are the major contents of the infratemporal fossa?

Answer 23

The medial pterygoid, the lateral pterygoid, the maxillary artery, CN V3, and the pterygoid plexus of veins.

Question 24

What are the articulate surfaces of the temporomandibular joint (TMJ)?

Answer 24

The condyle of the mandible and the articular tubercle of the temporal bone.

Question 25

What is the histology of the TMJ articular disc?

Answer 25

The articular disc of the TMJ is made of dense CT.

Question 26

What is the major ligament of the TMJ?

Answer 26

The sphenomandibular ligament.

Question 27

What is the innervation of all of the muscles of mastication?

Answer 27

The mandibular nerve (CV V3).

Question 28

What is the origin of the temporalis muscle?

Answer 28

The temporal lines and deep temporal fascia.

Question 29

What is the insertion of the temporalis?

Answer 29

The coronoid process and anterior surface of the ramus of the mandible.

Question 30

What is the function of the temporalis?

Answer 30

Elevates (closes) and retracts the jaw. It is the strongest muscle involved in closing the jaw.

Question 31

What is the origin of the masseter muscle?

Answer 31

The zygomatic arch.

Question 32

What is the insertion of the masseter muscle?

Answer 32

The external surface of the ramus of the mandible.

Question 33

What is the function of the masseter muscle?

Answer 33

Elevates (closes) the mandible.

Question 34

What is the origin of the medial pterygoid muscle?

Answer 34

The lateral pterygoid plate (part of the sphenoid) and the maxilla.

Question 35

What is the insertion of the medial pterygoid?

Answer 35

The internal surface of the ramus of the mandible.

Question 36

What is the function of the medial pterygoid?

Answer 36

Elevates (closes) the mandible and pivot movement of the mandible.

Question 37

What is the origin and insertion of the lateral pterygoid?

Answer 37

The lateral pterygoid plate (part of the sphenoid) and the infratemporal crest of the sphenoid bone.

Question 38

What is the function of the lateral pterygoid?

Answer 38

Protrusion and opening of the mandible; when acting unilaterally moves the jaw to the contralateral side to produce pivot movement during chewing.

Question 39

Where does the maxillary artery course to enter the infratemporal fossa?

Answer 39

The maxillary artery courses between the neck of the mandible and the sphenomandibular ligament to enter the infratemporal fossa.

Question 40

What are the three portions of the maxillary artery?

Answer 40

The mandibular, pterygoid, and pterygopalatine portions.

Question 41

Where is the mandibular portion of the maxillary artery located?

Answer 41

Deep to the neck of the mandible.

Question 42

What are the branches of the mandibular portion of the maxillary artery?

Answer 42

The middle meningeal artery and the inferior alveolar artery.

Question 43

Where does the middle meningeal artery course through?

Answer 43

Enters the middle cranial fossa via the foramen spinosum to supply the dura and skull.

Question 44

Where does the inferior alveolar artery course?

Answer 44

Enters the mandibular foramen to supply the mandible. mandibular teeth, and chin (via the mental branch).

Question 45

Where is the pterygoid portion of the maxillary artery located?

Answer 45

Courses through the infratemporal fossa.

Question 46

What are the major branches of the pterygoid portion of the maxillary artery?

Answer 46

Branches to the muscles of mastication as well as the buccal artery which supplies the cheek.

Question 47

Where is the pterygopalatine portion of the maxillary artery found?

Answer 47

Courses through the pterygopalatine fossa.

Question 48

What are the major branches of the pterygopalatine portion of the maxillary artery?

Answer 48

The posterior superior alveolar artery and the sphenopalatine artery.

Question 49

What is the pterygoid plexus of veins?

Answer 49

A large venous plexus within the infratemporal fossa. Coalesces to form the maxillary vein which then exits the infratemporal fossa travelling with the maxillary artery.

Question 50

Where does the mandibular nerve (CN V3) course?

Answer 50

Exits the cranial cavity via the foramen ovale to enter the infratemporal fossa.

Question 51

What GSA fibers does CN V3 convey?

Answer 51

GSA to the lower face.

Question 52

What SVE fibers does CN V3 convey?

Answer 52

SVE to all pharyngeal arch one muscles. The muscles of mastication and "matt" (mylohyoid, anterior belly of the digastric, tensor tympani, tensor veli palatini).

Question 53

What are the sensory branches (GSA) of CN V3?

Answer 53

The buccal nerve, lingual nerve, and auriculotemporal nerve.

Question 54

What are the motor branches (SVE) of CN V3?

Answer 54

SVE to pharyngeal arch one muscles.

Question 55

What are the mixed branches (GSA and SVE) of CN V3?

Answer 55

The inferior alveolar nerve.

Question 56

Where does the inferior alveolar nerve course?

Answer 56

Enters the mandibular foramen to supply the mandibular teeth. Gives off the mental nerve (exits the mental foramen to supply the chin w/ GSA) and the mylohyoid nerve (supplies the mylohyoid and anterior belly of the digastric).