anatomy

Question 1

what are the 4 muscles of mastication

Answer 1

• temporalis
• masseter
• medial pterygoid
• lateral pterygoid

Question 2

masseter description and origin -

Answer 2

thick quadrilateral muscle, originates from zygomatic arch (cheekbone). inserts into lateral surface of mandible

Question 3

what is the ramus of the mandible

Answer 3

the flattened posterior aspect of the mandible where the masseter inserts is the ramus

Question 4

main function and nerve supply of masseter…

Answer 4

 Main function- elevate the mandible (contracts – pulls the mandible up)
 Nerve supply from mandibular (third) division of the trigeminal nerve (CN V)

Question 5

temporalis description and origin -

Answer 5

Large fan shaped muscle located on lateral aspect of the head (side of head)
Takes its origin from several cranial bones (Frontal, Parietal, Temporal, Sphenoid) and the membranous tissue (Fascia) that covers it.
Runs inferiorly (downwards) passing deep into zygomatic arch and inserts into coronoid process of the mandible

Question 6

main function and nerve supply of temporalis…

Answer 6

 Vertical fibres- elevate the mandible/ closes mouth
 Horizontal fibres- retracts/ pull the mandible posteriorly (backwards)
 Nerve supply from mandibular (third) division of the trigeminal nerve (CN V)

Question 7

medial pterygoid description and origin -

Answer 7

located in an area that is medial to the ramus of the mandible, originated from the maxilla and the lateral pterygoid plate of the sphenoid
inserts into the medial surface of the mandibular ramus

Question 8

main function and nerve supply of medial pterygoid…

Answer 8

o Elevates mandible
o Side to side movement in the mandible
 Nerve supply from mandibular division of trigeminal nerve (CN V)

Question 9

lateral pterygoid description and origin -

Answer 9

located in an area that is medial to the ramus of the mandible (the infratemporal fossa)
arises as 2 heads - superior and inferior

Question 10

main function and nerve supply of lateral pterygoid…

Answer 10

o Superior head controls position of articular disk as the mouth is being closed
o Inferior head pulls mandible anteriorly as mouth opens and in side to side grinding of the mandible
• Nerve supply from mandibular division of trigeminal nerve (CN V)

Question 11

Inferior alveolar nerve-

Answer 11

this runs superficially (surface) to the medial Pterygoid muscle- when local anaesthetic applied here = stiff jaw

Question 12

Diagastric muscle -

Answer 12

 involved in opening the mouth
 Contains 2 bellies
1. Anterior belly- attaches to the mandible
2. Posterior- attaches to mastoid process of temporal bone
 2 bellies are connected by intermediate tendon
o intermediate tendon attaches to the hyoid bone

Question 13

main function and nerve supply of Diagastric muscle…

Answer 13

main function - assists in opening mouth

• Anterior belly supplied by mandibular division of trigeminal nerve (CN V)
• Posterior belly supplied by branch of the facial nerve (VN VII) –(Posterior digastric nerve).

Question 14

all the muscles of mastication receive their motor supply from ..?

Answer 14

• from branches of the mandibular division of the trigeminal nerve (also be called ‘the
  mandibular nerve’ or V3)
• The mandibular division of the trigeminal
  nerve is the only part of it to carry motor
  nerve fibres (it also contains many sensory
  fibres).

Question 15

the trigeminal nerve is the ….. cranial nerve?

Answer 15

fifth

Question 16

what is the cranium

Answer 16

skull without the mandible

Question 17

The buccinator description

facial muscle

Answer 17

• The buccinator attatches to the maxilla, the fibres run in the direction towards the mouth.
• The buccinator is a muscle of the cheek and attatches posteriorly to a fibrous band called the Ptergomandibular raphe

Question 18

Which two muscles attach to the raphe

Answer 18

Buccinator and superior constrictor (a muscle of the pharynx)

Question 19

Clinical importance of the raphe?

Answer 19

• The Raphe is important as local anaesthetics may be administered here

Question 20

the facial nerve is cranial nerve …?

Answer 20

7

Question 21

part of the facial nerve supplies motor function to the muscles of facial expression. where does this nerve go?

Answer 21

This part of the nerve leaves the skull and enters
the large salivary gland on the side of
the face – the parotid gland. Here it
divides into five sets of branches:
- temporal branches
- zygomatic branches
- buccal branches
- mandibular branches
- cervical branches

Question 22

What happens if aneedle is pushed too far when applying an inferior nerve block?

Answer 22

• If the needle is pushed too far when applying an inferior nerve block bells palsy Can occur.

Bells Palsy…
• Bells Palsy is usually caused by a virus that inflames the facial nerve while it is still travelling through the temporal bone.
• The condition ca resolve over many weeks. The condition can recur every few years. There can be an impact on patients lives during these “attacks”

Question 23

What are the 3 divisions of the trigeminal nerve

Answer 23

The trigeminal ganglion gives off three main
divisions:
The ophthalmic nerve (V1)
The maxillary nerve (V2)
The mandibular nerve (V3)

Question 24

What is the most important nerve (by far) in providing a

general sensory supply to the facial region?

Answer 24

cranial nerve V, the trigeminal nerve

Question 25

where do the superior and inferior heads of the lateral pterygoid attach

Answer 25

• superior head inserts into the articular disk of TMJ (temporomandibular joint)
• inferior head inserts into neck of mandible