Chewing, tasting and swallowing.

Question 1

What are the main muscles of mastication?

Answer 1

Temporalis
Masseter
Lateral pterygoid
Medial pterygoid

Question 2

Name the muscles involved in closing the mouth.

Answer 2

Temporalis
Masseter
Medial pterygoid (minor role)

Question 3

What is the main role of the medial pterygoid?

Answer 3

Swinging the mandible from side to side

Question 4

What is the function of the lateral pterygoid?

Answer 4

Opening the mouth (assisted by the digastric muscle)

Question 5

At which joint do the mandible and cranium articulate?

Answer 5

The temporomandibular joint.

Question 6

At rest where does the head of the mandible lie?

Answer 6

The glenoid fossa.

Question 7

With which muscle is the disc of fibrocartilage found in the glenoid fossa continuous?

Answer 7

The lateral pterygoid.

Question 8

Describe the movement of the mandibular head in the glenoid fossa. Why is this important?

Answer 8

The mandibular head rotates anteriorly and slides out of the fossa as the mouth opens. This freedom within the joint allows the mandibular head to move from side to side.

Question 9

How many heads does the lateral pterygoid muscle have and where do they insert?

Answer 9

Two, upper and lower. They insert into the neck of the mandible and part of the TMJ.

Question 10

What is the origin of the upper head of lateral pterygoid?

Answer 10

Sphenoid bone.

Question 11

What is the origin of the lower head of lateral pterygoid?

Answer 11

Lateral pterygoid plate.

Question 12

How does the lateral pterygoid open the mouth?

Answer 12

It pulls the neck of the mandible and parts of the TMJ forward, which protrudes the mandible but does not rotate it.

Question 13

Which muscle is responsible for the rotation of the mandibular head?

Answer 13

The digastric.

Question 14

What is the origin of the digastric muscle?

Answer 14

The mastoid process.

Question 15

What is unusual about the digastric muscle?

Answer 15

Is has two bellies - connected by a tendon.

Question 16

What is the origin of the temporalis?

Answer 16

The lateral surface of the skull.

Question 17

What is the insertion of the temporalis?

Answer 17

The choronoid process of the mandible.

Question 18

How does temporalis both elevate and retract the mandible?

Answer 18

The anterior fibres run in the verticle plane - elevating the mandible, while the posterior fibres run in the verticle plane - pulling temporalis back.

Question 19

What is the origin of the masseter?

Answer 19

The zygomatic arch.

Question 20

What is the insertion of the masseter ?

Answer 20

The choronoid process and the ramus of the mandible.

Question 21

What is the origin of the medial pterygoid?

Answer 21

The medial surface of the lateral pterygoid plate and the maxilla.

Question 22

What is the insertion of the medial pterygoid?

Answer 22

The inner aspect of the ramus of the mandible.

Question 23

What happens when the medial pterygoid contracts?

Answer 23

The mandible is pulled upwards and medially.

Question 24

Why does the lateral pterygoid also contract when the mouth is closing?

Answer 24

Confers extra control.

Question 25

Describe the innervation of the muscles of mastication.

Answer 25

They are all innervated by the mandibular branch of the trigeminal nerve (CNIII).

Question 26

Which nerve supplies the posterior belly of the digastric muscle?

Answer 26

The facial (CNVII).

Question 27

What is the name of the junction between the two parts of the tongue?

Answer 27

Sulcus terminalis

Question 28

What name is given to the structures of the posterior portion of the tongue located on the anterior surface?

Answer 28

Circumvallate pipillae

Question 29

What is the nerve supply to the posterior surface of the tongue.

Answer 29

General sensation, special sensation and taste are provided by lingual branches of the glossopharyngeal nerve (CNIX).

Question 30

Describe the nerve supply to the anterior surface of the tongue.

Answer 30

Taste sensation is provided by the facial nerve (CNVII) | General sensation is provided by the lingual nerve.

Question 31

What is the role of the tongue in swallowing?

Answer 31

The tongue is then raised against the hard palate progressively from anterior to posterior, thereby squeezing the bolus of food increasingly towards the back.

Question 32

What is the role of the soft palate in swallowing?

Answer 32

The soft palate is now tensed and elevated to close off the connection between the oropharynx and the nasopharynx, thereby preventing food being pushed upwards and into the nasal cavity.

Question 33

What is the role of the epiglottis during swallowing?

Answer 33

During the process of swallowing, as the tongue is elevated towards the hard palate, the larynx is drawn upwards. This brings the larynx up under the cover of the epiglottis. At the same time, the epiglottis is being bent backwards and downwards by the posterior bulging of the tongue and by the bolus of food itself.

Question 34

What is the role of the pharynx during swallowing?

Answer 34

The circular muscles of the pharynx contract successively from above downwards, generating a peristaltic wave that propels the bolus down through the pharynx and into the oesophagus.