Session 4: Anatomy of biting, chewing and swallowing [Complete]

Question 1

An alternative name for the mouth is?

Answer 1

Buccal cavity

Question 2

What are the 2 main folds in the mouth

Answer 2

Palatopharyngeal fold (palate [roof of the mouth] to pharynx)

Palatoglossal fold (palate to tongue)

Question 3

Where is the palantine tounsil located?

Answer 3

Between the palatopharyngeal and palatoglossal fols

Question 4

The posterior wall of the oral cavity is known as?

Answer 4

Oropharynx

Question 5

What is the uvula?

Answer 5

A part of the soft palate

Question 6

Why do doctors ask you to say ‘ahh’

Answer 6

Tests the vagus nerve (which provides most motor innervation to the levator veli palatini muscles)

The levator veli palatini muscles should cause the soft palate and uvula to lift up.

Question 7

What occurs if there is a problem with vagus nerve on one side of the soft palate

Answer 7

Levator velli palatini muscle won’t elevate, but the levator palatini muscle on the other side (where vagus is functioning) will elevate normal, so uvula will deviate towards the functioning side (which goes up!), so uvula will deviate AWAY from the lesion.

(OPPOSITE with tongue)

Question 8

What are the 3 components of the pharynx?

Answer 8

Nasopharynx

Oropharynx

Laryngopharynx

N.B. posterior to the airway is the opening of the oseophagus

Question 9

What is the name of the border between the nasopharynx and the oropharynx?

Answer 9

Pharyngeal isthmus /nasopharyngeal isthmus

Question 10

What structure is present at the border of the oropharynx and laryngopharynx?

Answer 10

The epiglottis

Question 11

How is food stopped from going down the airway?

Answer 11

You will raise the layrnx, you retroflex the epiglottis and cover the airway

Question 12

Describe the location of the hard and soft palate and describe their form

Answer 12

Hard palate is located anterioriorly and formed by the palatine process of the maxilla and horizontal plate of palatine bone, and spans the arch formed by the upper teeth

The soft palate is located posteriorly with the uvula in the midline

Question 13

Area where food can get stuck inc. fishbones

Answer 13

Piriform fossa which are located on either side of the laryngeal orifice

Question 14

Name the muscles of the pharynx and state their function.

Describe their sensory and motor innervations.

Answer 14

Constrictor muscle: pushes bolus into GI tract by sequential contraction.

There are superior, middle and inferior constrictor muscles

Sensory: IX (glossopharyngeal) and X (vagus) innervation via pharyngeal plexus

Motor: X (vagus) and (XI) [Accesory], constriction

Question 15

Outline stages of swallowing

Answer 15

The tounge is lifted and retracted via styloglossus and intrinsic muscles, causing the bolus to enter the oropharynx with the aid of the palatoglossus.

The bolus is prevented from entering the nasopharynx by raising the soft palate and closing it off. It is also prevented from entering the airway by raising the larynx and retroflex of the epiglottis.

Peristaltic waves of contraction from the constrictor muscles aid the bolus into the oesophagus and the cricopharyngeal muscle relaxes to provide an opening into the oesophagus

Question 16

State the names of the 3 pairs of salivary glands

Answer 16

Parotid (largest)

Sublingual

Submandibular

Question 17

What type of liquid comes from each salivary gland

Answer 17

Parotid and submandibular mainly serous

Sublingual maily mucus

Question 18

Which cranial nerves are each salivary gland supplied by

Answer 18

Parotid- IX (Glossopharyngeal)

Submandibular and sublingual- VII (Facial)

N.B. The facial nerve emerges from the parotid gland however it does not innervate it

Question 19

Where does the fluid drain into mouth from the parotid gland?

Answer 19

Via parotid duct, which opens above the upper second molar

Question 20

Which muscle does the parotid canal penetrate to get to thesecond molar?

Answer 20

Buccinator muscle

N.B Label incorrect it is the muscle you see the duct coming out of.

Question 21

List the muscles of the tongue and their points of attachment

Answer 21

Styloglossus - to styloid process of temproal bone= help to tounge to retract

Hyoglossus (to hyoid)

Genioglossus (to mandible)

intrinsic muscles

Question 22

Which cranial nerve supplies motor innervation to muscles of the tongue

Answer 22

XII [Hypoglossal]

Apart from palatoglossus which is innervated from vagus CNX.

Question 23

What is the attachment and function of the genioglossus?

Answer 23

Its function is to protrude the tongue

Genioglossus emerges from mandible (anteriorly) and inserts onto the tongue and hyoid bone

It protrudes the tongue when this muscle contracts (kind of pulls it forward towards mandible when this muscle shortens)

Question 24

How is the genioglossus function tested? What would happen to function if nerve supply was damaged on one side?

Answer 24

Ask them to stick tongue out.

If there is no innervation, the tongue is pulled forward on one side and not the other, and it pulls TOWARDS the lesion

Question 25

What is the lingual nerve function? What cranial nerves is it derived from?

Answer 25

Sensation as well as taste perception. Derived from mixed cranial nerve

Question 26

What is the name of the ganglion under the tongue? What type of innervation does it supply?

Answer 26

Submandibular ganglion. Provides vagus innervation to salivary glands

Question 27

Compare the sensation vs taste innervation of the tongue

Answer 27

Anterior 2/3. Taste= facial nerve (VII) Sensory= trigeminal (V) Posterior 1/3. Taste and sensation= glossopharyngeal (IX) and SOME vagus

Question 28

Where does taste perception begin?

Answer 28

nucleus solitarius in medulla

Question 29

List superficial muscles of mastication, their function and their innervation.

Answer 29

Masseter: zygomatic arch of zygomatic bone to the lateral surface of the ramus of the mandible It elevates the mandible, allowing forced closure of the mouth. Temporalis- THIN temporal fossa to coronoid process of mandible elevates and retracts mandible All mastication from trigeminal

Question 30

List the deep muscles of mastication and innervation

Answer 30

Lateral pterygoid: lateral pterygoid plate [of sphenoid] to the neck of mandible It depresses and protracts mandible to open mouth Medial pterygoid: lateral pterygoid plate of sphenoid/ maxilla/palate to angle of mandible It elevates and protracts and lateral movement of mandible for chewing Innervated by Trigeminal (vs buccinator is cn7)

Question 31

Where does the mandible articulate in the temporomandibular joint

Answer 31

It articulates into the mandibular fossa of the temporal bone

Question 32

What kind of joint is the temporomandibular joint?

Answer 32

Joint capsule Composed of two synovial cavities separated by articular disc

Question 33

What component of the temperomandibular joint is located most anteriorly?

Answer 33

the articular tubercle of the temporal bone anteriorly

Question 34

State the movement in the temporomandibular joint when opening the jaw slightly vs widely

Answer 34

Slightly- hinge action between the head of the mandible and the mandibular fossa of the temporal bone Widely opened- both hinge movement within the mandibular fossa, but the head of the mandible also GLIDES anteriorly to the articular tubercle of the temporal bone Reason of articular disc = allow protrusion/retraction as well as elevation/depression

Question 35

What can occur in anteriotly dislocated jaw dyslocation

Answer 35

Jaw opens so widely that it glides across the articular tubercle of temporal bone into the infratemporal fossa (where there are vessels and nerves)

Question 36

How can you put the mandible back in place?

Answer 36

Must put thumbs on back molars, push down (to get pass the articular tubercle) and then back into the mandibilar fossa

Question 37

At what level does the common carotid bifurcate?

Answer 37

Laryngeal prominence

Question 38

List the branches of the external cartotid artery

Answer 38

Superior thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial temporal

Question 39

What does the superior thyroid branch of the external carotid artery penetrate?

Answer 39

thyroid cartilage

Question 40

Why is the ascending pharyngeal artery hard to see?

Answer 40

It originates posteriorly

Question 41

Describe the route of the facial artey

Answer 41

Around the inferior border of the mandible up to medial canthas of the eye. It has a loop that allows movement as it goes around the mandible which is always opening and closing

Question 42

Which important artery emerges from the maxillary artery?

Answer 42

The middle meningeal artery----\> this branch comes through formaen spinosum

Question 43

Describe the course of the facial nerve.

Answer 43

It emerges from the pontomedullary junction,and then passes through the internal auditory meatus with the vestibulocochlear nerve (CN 8) It passes through the temporal bone and emerges from the stylomastoid foramen. It passes underneath the parotid and then the 5 branches of the facial nerve emerge from the anterior border of the parotid gland..... PAROTID GLAND IT NOT INNERVATED BY THE FACIAL NERVE

Question 44

List the 5 branches of the facial nerve emerging from the parotid.

Answer 44

Temporal zygomatic buccal mandibular cervical (supplying the platysma) N.B. You can test facial nerve by asking them to look up and should have creases in forehead

Question 45

Describe the course and then two branches of the mandibular nerve.

Answer 45

Mandibular nerve passes through the foramen ovale and then splits into: 1.Inferior alveolar nerve which passes into the back of the mandible and it travels through the mandible. It provides sensory nerves for lower dentition. (lower teeth) 2. The lingual nerve supplies sensory innervation to anterior 2/3 so contains V3 fibres. But it also has facial nerve branches from the chorda tympani (branch of the facial nerve emerging in the temporal bone). Information flow in chorda timpani is bidiretional as they are parasympathetic to submandibular ganglion (to submandibular and sublingual salivary gland) AND provide taste fibres from the anterior 2/3 of the tongue.

Question 46

What is the terminal branch of the inferior alveolar nerve?

Answer 46

The mental nerve (relating to mens=chin)

Question 47

How do you test V3 (mandibular branch) function of the trigeminal nerve?

Answer 47

should experience sensation to the chin

Question 48

Describe the dermatomes of head and neck

Answer 48

V1 (Opthalmic branch)= forehead + eyeball (corneal reflex) V2 (Maxillary branch) = below eyes + nose + cheeks + upper teeth V3 (Mandibular branch) = lower teeth + tongue + chin + thin strip of skin on lateral side of face going up to temples (think of sideburns) Posterior of head is C2-C3 Neck is C4-C5

Question 49

Describe the innervation of the buccal cavity

Answer 49

Hard palate: Greater palatine, nasopalatine nerves (both V2) Soft palate: lesser palatine nerve (V2) Floor of oral cavity: lingual nerve (V3) Cheeks: Buccal nerve (=V3, distinct from buccal branch of facial nerve.)

Question 50

What is the name and function of the recess at the back of the tongue?

Answer 50

Epiglottice vallecula (recess which allows saliva to collect until next swallow so the saliva doesn't constalty evoke a swallow reflex)