Functions 1

Question 1

Name the muscles of mastication (4)

Answer 1

1. Temporalis
2. Masseter
3. Lateral Pterygoid
4. Medial Pterygoid

Question 2

Origin of the masseter

Answer 2

Zygomatic arch

Question 3

Insertion of the masseter

Answer 3

Lateral surface + angle of the mandible

Question 4

Action of the masseter

Answer 4

Elevates the mandible

Question 5

How is the masseter examined?

Answer 5

Place 1 finger intra-orally and the other on the cheek

Question 6

In what patients is the master/temporalis tender?

Answer 6

Patients with a bruxism habit

Question 7

Origin of the temporalis

Answer 7

Floor of the temporal fossa

Question 8

Insertion of the temporalis

Answer 8

Coronoid process + anterior border of the ramus

Question 9

Action of the temporalis

Answer 9

Elevates + retract the mandible

Question 10

How is the temporalis examined

Answer 10

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

Question 11

Origin of the lateral pterygoid

Answer 11

From the lateral surface of the lateral pterygoid plate

Question 12

Insertion of the lateral pterygoid

Answer 12

Anterior border of the condyle + intra-articular disc via 2 independent heads

Question 13

Function of the lateral pterygoid

Answer 13

• Protrudes and laterally deviates the mandible

- The inferior head functions with the mandibular depressors during openings

Question 14

Where does the inferior belly of the lateral pterygoid attach

Answer 14

To the head of the condyle

Question 15

Where does the superior belly of the lateral pterygoid attach

Answer 15

Inserts into the intra-articular disc

Question 16

How is the temporalis examined digitally

Answer 16

Digital palpation between the superior and inferior temporal lines just above the ear, extending forwards towards the supra-orbital region

Question 17

How is the lateral pterygoid examined

Answer 17

Not accessible to manual palpation

Best examined by resisted movement tests

Question 18

What muscle is usually not examined in a dental practice

Answer 18

Medial pterygoid

Question 19

Origin of the medial pterygoid (2)

Answer 19

DEEP HEAD:
Medial surface of lateral pterygoid plate

SUPERFICIAL HEAD:
Tuberosity of the maxilla

Question 20

Insertion of the medial pterygoid

Answer 20

Medial surface of the angle of the mandible

Question 21

Action of the medial pterygoid

Answer 21

Elevates and assists in protrusion of the mandible

Question 22

Why is the medial pterygoid not examined? (2)

Answer 22

• Because of the location of the medial pterygoid, on the inside of the jaw its not available for palpation
• Also doesn’t respond well to resistive movement tests

Question 23

Whats the only muscle that can be hit following an injection?

Answer 23

Medial pterygoid

Will cause discomfort + annoyance but not a huge issue

Question 24

Effects of hitting the medial pterygoid

Answer 24

Trismus (temporary lock jaw)

Question 25

How is Inferior alveolar nerve block used efficiently?

Answer 25

Bone should be contacted to ensure correct position within the pterygomandibular triangular and not to hit the soft tissues

Question 26

Movements of the TMJ (2)

Answer 26

1. Rotation - Initial opening - Hinge movement 2. Translation - Wider opening - Sliding - Protrusive + retrusive movements

Question 27

What occurs during translation movements of the TMJ (2)

Answer 27

- As the mandible moves during protrusion, both condyles leave their fossa and move forward along the articular eminences - When the mandible retrudes, both condyles leave their eminences and move back into their respective fossa

Question 28

Maximum biting/clenching forces for molars

Answer 28

200-700N

Question 29

State psychological factors that could affect the results for maximum biting force results

Answer 29

Fear of tooth fracture could limit maximum biting force recorded

Question 30

State factors affecting maximum biting force (2)

Answer 30

1. Muscle mass - Bigger muscles = larger forces 2. Tooth type and position - Root area (PDL support)

Question 31

How does a hypertrophic masseter muscle present in a patient?

Answer 31

Unilateral chewing if one side is bigger

Question 32

What are the different muscle fibre types (3)

Answer 32

1. Type 1 - Slow low forces 2. Type 2 - Faster stronger forces 3. Sub types IIA, IIX, IIB

Question 33

What does predominant fibre type depend on (2)

Answer 33

1. Jaw morphology | 2. Diet

Question 34

What type of muscle fibre do people with square jaws have more of`?

Answer 34

More Type 2 fibres and can generate stronger bite forces

Question 35

Why do molars have the greatest bite forces?

Answer 35

Molars are nearer the force generating muscles and the TMJ

Question 36

Function of supra hyoid and infra hyoid muscles (2)

Answer 36

- Involved in mastication | - Play a role in stabilising the hyoid bone whilst we chew

Question 37

What makes up the suprahyoid muscles (4)

Answer 37

1. Digastric 2. Mylohyoid 3. Geniohyoid 4. Stylohyoid

Question 38

What makes up the infrahyoid strap muscles (4)

Answer 38

1. Sternohyoid 2. Sternothyroid 3. Thyrohyoid 4. Omohyoid

Question 39

What examples for the suprahyoid muscles act as jaw depressors (3)

Answer 39

1. Digastric 2. Mylohyoid 3. Geniohyoid

Question 40

What are the different types of tongue muscles (2)

Answer 40

1. Intrinsic (alter shape) | 2. Extrinsic (alter shape + position)

Question 41

Examples of intrinsic tongue muscles (3)

Answer 41

1. Longitudinal 2. Vertical 3. Transverse

Question 42

Examples of extrinsic tongue muscles (4)

Answer 42

1. Genioglossus 2. Hypoglossus 3. Palatoglossus 4. Styloglossus

Question 43

Function of facial muscles

Answer 43

Help to control food bolus and prevent spillage

Question 44

Examples of facial muscles (2)

Answer 44

1. Orbicularis oris | 2. Buccinator