Oral function 1: muscles Flashcards Preview

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Flashcards in Oral function 1: muscles Deck (57)
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1
Q

why is the term muscles of mastication misleading

A

because many other muscles are involved in mastication

the term mandibular muscles is suggested as an alternative

2
Q

what is the origin of the masseter

A

zygomatic arch

3
Q

what is the insertion of the masseter

A

lateral surface and angle of mandible

4
Q

what is the action of the masseter

A

elevates the mandible

5
Q

which patients may have a tender masseter

A

those who have a clenching habit

6
Q

how do we examine the masseter

A

place on finger intra orally and the other on the check

7
Q

what is the origin of the temporalis

A

floor of temporal fossa

8
Q

what is the insertion of the temporalis

A

coronoid process and anterior border of ramus

9
Q

what is the action of the temporalis

A

elevates and retracts mandible

10
Q

which patients have a tender temporalis

A

patients who have a bruxism habit

11
Q

how do you examine the temporalis

A

palpate its origin by asking the patient to clench the teeth together

12
Q

how is digital palpation performed on the temporalis

A

it is performed between the superior and inferior temporal lines just above the ear, extending forwards towards the supra-orbital region

13
Q

what is the origin of the lateral pterygoid

A

from the lateral surface of the lateral pterygoid plate

14
Q

what is the insertion of the lateral pterygoid

A

anterior border of the condyle and intraarticular disc via two independent heads

15
Q

what is the function of the lateral pterygoid

A

protrudes and laterally deviates the mandible and the inferior head functions with the mandibular depressors during openings

16
Q

what does the inferior belly of the lateral pterygoid attach to

A

head of the condyle

17
Q

what does the superior belly of the lateral pterygoid insert into

A

intra articular disc

18
Q

how do we examine the lateral pterygoid

A

not accessible to manual palpation
best examined by recording its response to resisted movement
good correlation between the resisted movement test and the muscle being tender to palpitation

19
Q

what is the origin of the deep head of the medial pterygoid

A

medial surface of the lateral pterygoid plate

20
Q

what is the origin of the superficial head of the medial pterygoid

A

tuberosity of the maxilla

21
Q

what is the insertion of the medial pterygoid

A

medial surface of the angle of the mandible

22
Q

what is the action of the medial pterygoid

A

elevates and assists in protrusion of the mandible

23
Q

why is the medial pterygoid not available for palpation

A

because of its location inside of the jaw

24
Q

why is there no way of examining the medial pterygoid

A

does not respond well to resistive movement tests

25
Q

why should bone be contacted when giving ID block

A

to ensure correct position within the pterygomandibular triangle and not to hit the soft tissues

26
Q

what happens happens if you accidentally hit the medial pterygoid when giving ID block

A

trismus

27
Q

what are the movements of the TMJ

A

rotation - initial opening

translation - wider opening

28
Q

what happens in protrusion of the mandible

A

both condyles leave their fossa and move forward along their aritucular eminences

29
Q

what happens in retrusion of the mandible

A

both condyles leave the eminences and move back into their respective fossa

30
Q

what is the maximum biting/clenching forces

A

varies between teeth

maximum between molars is 200-700N

31
Q

what are the psychological factors that effect the biting/clenching forces

A

fear of tooth fracture when maximum forces are used which can limit the maximum biting force recorded

32
Q

how does muscle mass affect maximum biting force

A

bigger muscles = larger force

33
Q

what are the muscle fibre types

A
type I 
type II 
sub types (IIA, IIX, IIB)
34
Q

what are type I muscle fibers

A

slow, low forces

35
Q

what are type II muscle fibers

A

fast, stronger forces

36
Q

what are the sub type muscle fibres

A

predominant fibre type varies, depending on jaw morphology, diet

37
Q

what do people with squarer jaws have more of which muscle fibres

A

type 2

can generate stronger btiting forces

38
Q

which teeth generate the greatest biting forces

A

1st molars

39
Q

what else effects force

A

tooth type and position
position relative to TMJ and muscles
root area - PDL support

40
Q

what are the supra hyoid muscles

A

digastric
mylohyoid
geniohyoid
stylohyoid

41
Q

what are the infra hyoid ‘strap’ muscles

A

sternohyoid
omohyoid
thyrohyoid
sternothyroid

42
Q

what muscles act as jaw depressers

A

digastric
mylohyoid
geniohyoid

43
Q

what do this intrinsic tongue muscles do

A

alter shape

44
Q

what do the extrinsic tongue muscles do

A

alter shape and position

45
Q

what are the intrinsic tongue muscles

A

longitudinal
vertical
transverse

46
Q

what are the extrinsic tongue muscles

A

genioglossus
hypoglosus
palatoglossus
styloglossus

47
Q

what do the facial muscles do

A

help to control food bolus and prevent spillage

48
Q

what are the facial muscles

A

orbicularis oris

buccinator

49
Q

What is Posselt’s envelope

A

the envelope of mandibular movements in the sagittal plane

50
Q

What are the 5 points on Posselt’s envelope

A
RCP
ICP
edge to edge
fully protruded
fully open
51
Q

What is the ICP

A

The intercuspal position is the ‘habit position’ where maximum intercuspation occurs. When you tell a patient to bite together, usually this is the position they adopt.

52
Q

As the jaw protrudes towards end-to-end position what is it guided by

A

its position is guided by the cusps of the teeth (anterior determinants) and the slope of the fossae (posterior determinants

53
Q

When the mandible opens how does it open (Posselt’s envelope)

A

opens in a smooth arc. The condylar head repositions as the jaw opens.

54
Q

When the mandible closes how does it close (posselt’s envelope)

A

As the jaw closes to the RCP it does not make a smooth arc, only when the teeth are nearly together is the movement smooth.

55
Q

What is the mnemonic for the supra hyoid muscles

A

my gravy spoon, darling

56
Q

What is the mnemonic for infrahyoid mouses

A

TOSS

57
Q

What is the mnemonic for the tongue muscles

A

SH the GP