L11 trigeminal nerve , mastication & TMJ

Question 1

what are the main divisions of the mandible?

Answer 1

• the body
• the ramus

Question 2

what is the point at which the ramus and body** join** on the mandible?

Answer 2

the** angle** of the mandible

Question 3

what are the 2 subparts of the body of the mandible?

Answer 3

• the base - forms the lower portion of the mandible
• the alveolar part holds the lower teeth

Question 4

Whar is the TMJ?

function, location etc

Answer 4

• the** temporomandibular joint** connects the skull to the mandible
• located between the mandibular fossa and articular tubercle of the temporal bone &** condylar process of the mandible **

Question 5

what are the digastric fossae of the mandible?

Answer 5

the** attachment sites **for the left and right anterior bellies of digastric muscles

Question 6

what are the mental foramina of the mandible?

Answer 6

• foramina located halfway between the base and alveolar part of mandible
• they form the opening of the mandibular canal which transports the inferior alveolar nerve & vessels

Question 7

what are the mandibular condyles?

Answer 7

part of mandible that allows it to articulate with temporal bone via TMJ

Question 8

what is the function of the articular disc in the TMJ?

Answer 8

• divides the joint into 2 anatomically and functionally seperate compartments - superior and inferior compartment and each compartment is lined by its own synovial membrane

Question 9

Describe the** superior compartment** of the TMJ?

Answer 9

• this compartment is bordered superiorly by the manidbular fossa of temporal bone and inferiorly by the articular disc
• responsible for translational movement of the joint

Question 10

Describe the inferior compartment of the TMJ - describe boundaries and what movement it allows

Answer 10

• bounded superiorly by the articular disc and inferiorly by the condyle of the mandible
• allows rotational movement of the joint

Question 11

what are the 2 extrinsic ligaments of the TMJ?

Answer 11

• stylomandibular (runs from styloid process to mandible)
• sphenomandibular (runs from sphenoid to mandible)

Question 12

what are the 4 muscles of mastication?

Answer 12

1. the temporalis muscle
2. the masseter muscle
3. the medial pterygoid muscle
4. the lateral pterygoid muscle

Question 13

Describe the masseter muscle

Answer 13

• rectangular in shape
• seperated into 2 layers - known as the superficial and deep layers

Question 14

Describe the superficial layer of the masseter muscle

ie where it originates from and where it attaches

Answer 14

• originates from the maxillary process of the zygomatic bone and the anterior 2/3 of the zygomatic arch
• muscle inserts itself onto the lateral surface of the ramus of the mandible

Question 15

Describe the **deep layer **of the masseter muscle

ie where it originates from and where it attaches

Answer 15

• this part originates from the deep or interior surface of the posterior of the third zygomatic arch
• much larger muscle layer than the superficial (not seen in pic)
• inserts along the lateral surface of the ramus

Question 16

what branch of the mandibular nerve (V3) innervates the masseter muscle?

Answer 16

the masseteric nerve

Question 17

what is the function of the masseter muscle?

Answer 17

• elevates/ draws up the mandible
• ie helps to close mandible so you can chew food

Question 18

Describe the temporalis muscle

Answer 18

• muscle located on the lateral side of the skull
• covers a large part of the temporal bone

Question 19

Where does the temporalis muscle originate from and where does it run too?

Answer 19

• originates from the** temporal fossa**
• temporalis descends through gap between zygomatic arch and the skull forming a thick tendon which **inserts into the coronoid process of the mandible **

Question 20

what branches of the mandibular nerve (V3) is the temporalis innervated by?

Answer 20

the anterior and posterior deep temporal branches of the mandibular nerve (V3)

Question 21

what is the function of the temporalis muscle?

Answer 21

elevates and retracts (pulls it backwards)
* ONLY MUSCLE THAT PERFORMS RETRACTION OF MANDIBLE

Question 22

what are the two heads of the lateral pterygoid muscle?

Answer 22

1. upper head
2. lower head

Question 23

where does the upper head of the lateral pterygoid muscle originate from?

Answer 23

**greater wing **of sphenoid bone

Question 24

where does the **lower head **of the lateral pterygoid muscle originate from?

Answer 24

lateral surface of lateral pterygoid plate of the sphenoid bone

Question 25

where do the heads of the lateral pterygoid muscle** insert onto**?

Answer 25

the heads fuse onto the pterygoid fossa of the mandibular condyle

Question 26

what branches of the mandibular nerve innervate the lateral pterygoid muscle?

Answer 26

lateral pterygoid nerves

Question 27

what functions does the **lateral pterygoid muscle** have?

Answer 27

* **protruding mandible** - ie sticking it out * **depression of mandible** - moving it downwards * upper head inserted into the TMJ capsule - therefore it** pulls the articular disc anteriorly ** * can also cause **side to side movements **of mandible

Question 28

like the masseter muscle, what are the 2 layers of the medial pterygoud muscle?

Answer 28

the **superficial and deep layer**

Question 29

where does the deep head of the medial pterygoid muscle arise/originate from?

Answer 29

the **medial surface **of the** lateral plate** of the** pterygoid process of the sphenoid bone**

Question 30

where does the** superficial head **of the medial pterygoid muscle originate from?

Answer 30

the **maxillary tuberosity** (located just beneath wisdom teeth)

Question 31

**where** do the** superficial and deep heads** of the **medial pterygoid muscle** join?

Answer 31

* **medial aspect** of the **angle** of the **mandible **

Question 32

what is the **function of the medial pterygoid muscle**?

Answer 32

elevation of the mandible so you can close teeth and chew

Question 33

what **branch of the mandibular nerve** innervates the **medial pterygoid muscle**?

Answer 33

medial pterygoid nerve

Question 34

what** type of nerve** is the trigeminal nerve?

Answer 34

mixed nerve - ie has both motor and sensory functions

Question 35

what **motor functions **does the trigeminal nerve have? | what different muscles ?

Answer 35

* innervates the** muscles of mastication** * innervates the** mylohyoid muscle** (1of the 4 suprahyoid muscle ) * innervates the** anterior belly of the digastric muscle ** * innervates the** tensor tympani muscles** (muscle within middle ear)

Question 36

what sensory functions does the trigeminal nerve have?

Answer 36

provides sensory functions to the * scalp * face * orbit * paranasal sinuses * anterior 2/3 of tongue

Question 37

what are the **3 divisions** of the trigeminal nerve? | IE MOM

Answer 37

1. ophthalamic nerve (V1) 2. maxillary nerve (v2) 3. mandibular nerve (v3)

Question 38

**where** is the **ganglion** of the **trigeminal nerve** located?

Answer 38

* located in **Meckel's cave** (near petrous part of temporal bone) within the middle cranial fossa

Question 39

what are the branches of the ophthalamic nerve ?

Answer 39

* frontal nerve * lacrimal nerve * nasocillary nerve

Question 40

what does the frontal nerve (branch of ophthalamic nerve) branch into?

Answer 40

the **supraorbital **nerve and **supratrochlear** nerve

Question 41

where does the supraorbital nerve pass through ?

Answer 41

the supraorbital foramen

Question 42

through which fissure, does the opthalamic nerve exit the cranial cavity?

Answer 42

the superior orbital fissure

Question 43

through which foramen does the maxillary nerve exit the cranial cavity?

Answer 43

foramen rotundum (opening in the greater wing of sphenoid bone)

Question 44

through which** foramen** does the **mandibular nerve **exit the cranial cavity?

Answer 44

formane ovale (middle bigger hole located on greater wing of sphenoid bone)

Question 45

what **branche of the maxillary nerve** (V2) supplies the buccal (cheek) region of face and jaw?

Answer 45

the infraorbital nerve - runs through the cranium to supply the gums,pulp, mucosa and PDL of teeth

Question 46

what 2 branches come off the infraorbital nerve (branch of V2)

Answer 46

* anterior superior alveolar nerve * middle superior alveolar nerve

Question 47

after the infraorbital gives off the 2 branches (ASAN and MAAN), where does it exit?

Answer 47

it exits through the **infraorbital foramen**

Question 48

what **3 branches** of the maxillary nerve supply the lingal region of the face and jaw?

Answer 48

1. **lesser palatine nerve **- soft palate 2. **greater palatine nerve** - gums, teeth (3-8)and mucosa of hard palate .. not PULP 3. **nasopalatine nerve** - gums, teeth (1-3) of hard palate .. not pulp

Question 49

what **2 branches **of the** mandibular nerve (V3**) supply the** lingual region** of the face and jaw?

Answer 49

*** lingual nerve** - runs on lingual surface of mandible *** inferior alveolar nerve** - goes through mandibular foramen and canal

Question 50

# **** Describe the **2 branches** of the **mandibular nerve** (V3) supply the** buccal region **of the face and jaw?

Answer 50

1. **inferior alveolar nerve** - enters **mandibular foramen** and** travels through mandibular canal** - exits mental foramen where it branches into the **mental nerve ** 2. **buccal nerve** - runs across retromolar space (space beside 3rd molar) to supply cheek, gums, oral mucosa, PDL etc

Question 51

What is the chorda tympani nerve? | side note - to do with tongue

Answer 51

a branch of the facial nerve that provides TASTE SENSATION to the tongue