Muscles involved in opening and closing of mouth

Question 1

Shark opening muscles

Answer 1

levator hyomandibulae, epaxial, coracomandibularis, rectus cervicis, hypaxial

Question 2

Levator hyomandibulae

Answer 2

moves hyomandibula dorsally

Question 3

Epaxial

Answer 3

moves cranium caudally

Question 4

Coracomandibularis

Answer 4

moves meckel’s cartilage caudally

Question 5

Rectus cervicis

Answer 5

moves hyoid arch cardally

Question 6

Hypaxial

Answer 6

stabilizes coracoid or pectoral girdle

Question 7

Palatoquadrate movement during opening

Answer 7

moves ventrally because it’s not fused to the skull and the hyomandibular is pulled dorsally

Question 8

Shark closing muscles

Answer 8

levator palatoquadrati, preorbitalis, interhyoideus, intermandibularis, adductor mandibulae

Question 9

Levator palatoquadrati

Answer 9

moves palatoquadrate towards chondrocranium

Question 10

Preorbitalis

Answer 10

moves meckel’s cartilage towards orbits of chondrocranium

Question 11

Adductor mandibulae

Answer 11

moves meckel’s cartilage towards base of chondrocranium

Question 12

Interhyoideus and intermandibularis

Answer 12

moves hyoid towards meckel’s cartilage

Question 13

Salamander opening muscles

Answer 13

depressor mandibulae, geniohyoideus, epaxial, sternohyoideus (rectus cervicis), hypaxial

Question 14

Depressor mandibulae

Answer 14

unique to amphibians and opening can occur without the need of the depressor, moves the back of lower jaw towards skull

Question 15

Sternohyoideus within salamander

Answer 15

moves the hyoid caudally

Question 16

Salamander closing muscles

Answer 16

geniohyoideus, adductor mandibulae

Question 17

Geniohyoideus of salamander

Answer 17

connects the mandible to the hyoid arch and is involved in both opening and closing. during opening the hyoid is moved caudally so geniohyoideus contracts and the lower jaw is also brought down/caudally. during closing the hyoid is stable so when geniohyoideus contracts the lower jaw is closed and pulled forward

Question 18

Mammal opening phases

Answer 18

slow then fast

Question 19

Mammal closing phases

Answer 19

fast then slow

Question 20

Mammal slow opening muscles

Answer 20

geniohyoideus, anterior digastric, posterior digastric, masseter and pterygoid

Question 21

Mammal fast opening muscles

Answer 21

geniohyoideus, anterior digastric, sternohyoideus, posterior digastric

Question 22

Masseter and pterygoid

Answer 22

stabilizes the jaw joint to allow the mouth to be slightly open

Question 23

Sternohyoideus of mammal

Answer 23

will pull back on the taught lower jaw

Question 24

Posterior digastric, anterior digastric and geniohyoideus

Answer 24

constricts and stabilizes lower jaw to make it taught

Question 25

Mammal slow closing muscles

Answer 25

posterior digastric, sternohyoideus, masseter, pterygoid, temporalis

Question 26

Mammal fast closing muscles

Answer 26

posterior digastric, sternohyoideus, masseter, pterygoid, temporalis

Question 27

Posterior digastric

Answer 27

will stabilize the hinge of the back of the jaw during fast closing and will stabilize the hyoid during slow closing

Question 28

Sternohyoideus within mammal

Answer 28

will pull the lower jaw backwards during fast closing and pull the hyoid to its original resting position during slow closing