Muscles

Question 1

mandibular muscles

Answer 1

masseter
temporalis
lateral pterygoid
medial pterygoid

Question 2

masseter

Answer 2

origin - zygomatic arch
insertion - lateral surface and angle of mandible
action - elevates mandible

tender when clencing, place intra orally and on cheek

Question 3

temporalis

Answer 3

origin - floor of temporal fossa
insertion - coronoid process, anterior border of ramus
action - elevates and retracts mandible

largest, in zygomatic arch, tender in brixism, clench to test

Question 4

lateral pterygoid

Answer 4

origin - lateral surface of lateral pterygoid plate
insertion - anterior vorder of condyle, intra-articular disc
function - protrudes and laterally deviate mandible

inferior belly attaches t head of condyle, superior belly inserts to intra-articular disc

Question 5

medial pterygoid

Answer 5

origin - deep, medial surface of lateral pterygoud plate
insertion - medial surface of angle of mandible
action - elevates and assists in protrusion of mandible

cant palpate, no way to examin
if trismus = this has been hit in LA

Question 6

movements of TMJ

Answer 6

rotation - initial opening, open and close
translation - wider opening, protrusive and retrusive movements, sliding
- condyls leave fossae and move forward when prtrusion, rotrusion returns back

Question 7

posselts envelope of motion/movement

Answer 7

refers to range of motion of mandible
diagram of saggital view of maximum mandibular movement

20mm, only ritates

Question 8

maximum biting/clenching forces

Answer 8

varies in teeth, 200-700N in molars
psychological - fear of fracture
factors affecting - muscle mass, parafunction [bruxism]

Question 9

muscle fibre types

Answer 9

type 1 - slow, low forces
type 2 - fast, stronger forces
substypes [IIA, IIX, IIB]
- preodminant fibre type baries, squarer jaws have more type 2 so stronger

Question 10

where is the greatest bite force

Answer 10

between 1st molars
relative to TMJ and muscles [near generating muscle forces]
root area - PDL support

Question 11

suprahyoid muscles

Answer 11

digastric
mylohyoid
geniohyoid
stylohyoid

Question 12

infrahyoid ‘strap’ muscles

Answer 12

sternohyoid
omohyoid
thyroihyoid
sternothyroid

Question 13

intrinsic tongue muscles

Answer 13

alter shape
longitudinal
vertical
transverse

Question 14

extrinsic tongue muscles

Answer 14

alter shape and position
genioglossus
hyoglossus
palatoglossus
styloglossus

Question 15

facial muscles and feeding

Answer 15

helps control food bolus and prevent spillage
- orbicularis oris and buccinator
keeps food between lips and teeth while chewing