Tmj Muscles

Question 1

Muscles Of Mastication

Answer 1

• Masseter
• Temporalis
• Lateral Pterygoid
Medial Pterygold

Question 2

contains medial and lateral pterygold and the tendon of temporalis.

Answer 2

Infratemporal fossa

Question 3

• lies on the face, on the lateral surface of the ramus of the mandible

quadrilateral muscle

consists of three layers that blend anteriorly.
• Superficial layer
•Middle layer
Deep layer

Answer 3

Masseter muscle

Question 4

Masseter consist of three layer that blend anteriorly

Answer 4

Superficial layer
•Middle layer
Deep layer

Question 5

is the largest layer of Masseter
Arises by a thick aponeurosis from the
• maxillary process of the zygomatic bone

Anterior two-thirds of the inferior border of the zygomatic arch.

Answer 5

Superficial layer

Question 6

It’s fibers pass downwards and backwards

insert into the angle and lower posterior half of the lateral surface of the mandibulor ramus.

Answer 6

Superficial layer

Question 7

angled approximately 10°
from the vertical, as is visible in lean individuals.
• in the coronal (frontal) plane, the muscle forms a 10° angle with the mandibular ramus.
intramuscular tendinous septa in this layer are responsible for the ridges on the surface of the ramus.

Answer 7

Superficial layer

Question 8

Arises from the:
medial aspect of the anterior two-thirds of the
zygomatic arch

lower border of the posterior third of the
zygomatic arch.

Answer 8

Middle layer

Question 9

Insert into the central part of the ramus of the mandible.

Answer 9

Middle layer

Question 10

Arises from the deep surface of the zygomatic arch

inserts into the upper part of the mandibular ramus
and into its coronoid process.

Answer 10

Deep layer

Question 11

deep fibers run vertically and are evident just anterior to the temporomandibular joint, where they are not covered by the more superficial layers.

Answer 11

Deep layer

Question 12

The anterior margin of masseter is:

Answer 12

separated from buccinator and the buccal branch of the mandibular nerve by a buccal pad of fat

crossed by the facial vein.

Question 13

Overlapped by the parotid gland

Answer 13

Posterior margin of muscle

Question 14

reach the deep surtace of masseter by passing over the mandibular incisure (mandibular notch).

Answer 14

The masseteric nerve and artery

Question 15

Vascular supply

Answer 15

masseteric branch of the maxillary artery

•facial artery

transverse facial branch of the
superficial temporal artery.

Question 16

Masseter action

Answer 16

elevates the mandible to occlude the teeth in mastication

• has a small effect in side-to-side movements. protraction and retraction.

Its electrical activity in the resting position of the mandible is minimal.
OLe

Question 17

Action Masseter

Answer 17

elevates the mandible to occlude the teeth in mastication

• has a small effect in side-to-side movements. protraction and retraction.

Its electrical activity in the resting position of the mandible is minimal.

Question 18

Arises from the

whole of the temporal fossa up to the inferior temporal line - except the part formed by the zygomatic bone

• deep surface of the temporal fascia.

Answer 18

Temporalis muscle

Question 19

its fibers converge and descend into a tendon that passes through the gap between the zygomatic arch and the side of the skull.

Attached to the medial surface, apex, anterior and posterior borders of the coronoid process and
to the anterior border of the mandibular ramus almost up to the third molar tooth.

Answer 19

Temporalis muscle

Question 20

•anterior fibers are orientated vertically.
• the most posterior fibers almost horizontally
• the intervening fibres with intermediate degrees of obliquity. in the manner of a fan.

Answer 20

Temporalis muscle

Question 21

may occasionally gain attachment to the articular disc.

Answer 21

Fibers of Temporalis

Question 22

•supplied by deep temporal branches from the second part of the moxillary artery, which enter on its deep aspect, and middle temporal branches from the superficial temporal artery, which enter on its lateral aspect.
• The anterior deep temporal artery supplies 20% of the muscle anteriorly:

Answer 22

Vascular supply

Question 23

•the posterior deep temporal artery, entering the mid-portion of the muscle, supples 40% of the muscle in the mid-region; and the middle temporal artery, entering the muscle posteriorly, supplies 40% of the muscle in its posterior region.

• Considerable vascular anaslomoses are present within the muscle

Answer 23

Vascular supply

Question 24

Innervation vascular supply

Answer 24

•anterior, middle and posterior deep temporal branches of the anterior trunk of the mandibular nerve.

Question 25

Actions vascular supply

Answer 25

elevates the mandible and so closes the mouth and approximates the leeth.
• IThis movement requires both the upward pull of the anterior fibers and the backward pull of the posterior fibers because the head of the mandibular condyle rests on the articular eminence when the mouth is open.)

Question 26

•also contributes to side to-side grinding movements.
“the posterior fibers retraci the mandible after it has been protruded.
• The posterior fibers of temporalis, which are almost horizontal, are the only source of mandibular retrusion.

Answer 26

Actions vascular supply

Question 27

are the two deep pairs of the muscles of mastication.

they attach to the lateral and medial sides of the Lateral pterygold plates of the sphenoid bone respectively.

Answer 27

Lateral and Medial pterygoid muscles

Question 28

• thick triangular muscle
• fibers are oriented HORIZONTALLY
• like the medial pterygoid muscle has two heads

Answer 28

Lateral pterygoid muscle

Question 29

Upperhead lateral pterygoid muscle

Answer 29

originates from the roof of the infra-temporal fossa lateral to the foramen ovale and foramen spinosum.

(Infratemporal fossa - Inferior surface of the greater wing of the sphenoid and the infratemporal crest)

Question 30

is larger than the upper head
originates from the lateral surface of the lateral plate of the pterygoid process,

•the inferior part insinuates Itself between the cranial attachments of the two heads of the medial pterygoid.

Answer 30

Lower head lateral pterygoid muscle

Question 31

The fibers from both heads of the lateral pterygoid muscle converge to insert

Answer 31

Into the pterygold fovea of the neck of the mandible and

into the capsule of the temporo-mandibular joint in the region where the capsule is attached internally to the articular disc.

Question 32

Oriented vertically pterygoid muscle

Muscle oriented vertically

Answer 32

Medial pterygoid

Question 33

pterygoid muscle oriented almost horizontally.

Answer 33

Lateral pterygoid

Question 34

contracts it pulls the articular disc and head of the mandible forward onto the articular tubercle and is therefore the

MAJOR PROTRUDER of the lower jaw.

Answer 34

Lateral pterygoid

Question 35

•When the lateral and medial pterygoids contract on only one side.

Answer 35

The chin moves to the opposite side

Question 36

When opposite movements at the two temporomandibular joints are coordinated,

Answer 36

A chewing movement results

Question 37

assumed a specialized role in mandibular opening that is medialed by its horizontally onenfated fibres.

Answer 37

Lateral pterygoid

Question 38

When left and right muscles of lateral pterygoid contract together,

Answer 38

the condyle is pulled forwards and slighily downwards.

Question 39

main jaw opening muscles

Answer 39

Digastric and geniohyoid