20 - Oral cavity

Question 1

What are the borders of the oral cavity?

Answer 1

Roof - hard and soft palate
Floor - tongue, floor of mouth
Lateral walls - cheeks
Anterior - oral fissure, lips
Posterior - oropharyngeal isthmus

Question 2

What is the oral vestibule?

Answer 2

Area between teeth and cheeks

Question 3

What is the oral cavity proper?

Answer 3

Area from the teeth to the oropharyngeal isthmus

Question 4

Describe the lips.

Answer 4

• mobile musculo-fibrous folds
• lined externally by skin and internally by oral mucosa
• orbicularis oris is the main muscular contribution

Question 5

What is the philtrum?

Answer 5

Depression in the midline above the upper lip

Question 6

What is the blood supply of the lips?

Answer 6

Labial arteries are branches of the facial artery, which anastomose together to form an arterial ring

Question 7

What is the sensory innervation of the lips?

Answer 7

Upper - CN V2 (infraorbital)
Lower - CN V3 (mental)

Question 8

What is the lymphatic drainage of the lips?

Answer 8

• submandibular nodes
• except for lower middle lip which drains to the submental nodes

Question 9

Describe the cheeks.

Answer 9

• lateral moveable walls of oral cavity
• continuous anteriorly with lips
• composed of muscle and fascia, lined externally with skin and internally with oral mucosa

Question 10

What is the main muscular component of the cheeks?

Answer 10

Buccinator

Question 11

Where is the buccal fat pad located?

Answer 11

Superficial to buccinator

Question 12

What is the blood supply of the cheeks?

Answer 12

Maxillary artery

Question 13

What is the sensory innervation of the cheeks?

Answer 13

Buccal branches of CN V3

Question 14

What is the motor innervation of the cheeks?

Answer 14

Buccal branch of CN VII

Question 15

What are key features of the oral vestibule?

Answer 15

• labial frenulum (connects gingiva to lips) in midline
• buccal frenulum laterally
• papilla of parotid duct (near maxillary 2nd molar)

Question 16

What forms the floor of the mouth?

Answer 16

• muscular diaphragm by paired mylohyoid muscles
• mylohyoid muscles attach from the mylohyoid line on mandible to body of hyoid and into each other, forming the raphe in the midline
• paired geniohyoid muscles sit superior to the mylohyoid raphe

Question 17

What separates the anterior 2/3 and posterior 1/3 of the tongue?

Answer 17

Terminal sulcus and valate papilllae

Question 18

What are the different types of tastebuds?

Answer 18

• fungiform
• foliate
• vallate
• filiform

Question 19

Describe fungiform papillae.

Answer 19

• mushroom like
• appear as red spots
• numerous at apex and margins

Question 20

Describe foliate papillae.

Answer 20

Folds of mucosa lining posterior and lateral superior surface of tongue

Question 21

Describe vallate papillae.

Answer 21

• largest papillae
• arranged in V shape anterior to terminal sulcus
• surrounded by circular trenches
• tastebuds are within the trenches
• serous glands empty into trenches

Question 22

Describe filiform papillae.

Answer 22

• only papillae without tastebuds
• conical projections with efferent nerve endings

Question 23

What is the function of the papillae on the surface of the tongue?

Answer 23

Grip food and house tastebuds

Question 24

Describe the inferior surface of the tongue.

Answer 24

• thin transparent mucosa is continuous with that of the floor of the mouth
• midline marked by frenulum of the tongue
• deep lingual vein can be seen either side of frenulum
• sublingual caruncle houses submandibular duct
• sublingual ducts open laterally to sublingual caruncle

Question 25

What is the function of intrinsic tongue muscles?

Answer 25

Change the shape and size of tongue

Question 26

What are the intrinsic tongue muscles?

Answer 26

- superior longitudinal - inferior longitudinal - vertical - transverse

Question 27

What is the function of the extrinsic tongue muscles?

Answer 27

- originate from outside the tongue - protrude, retract, elevate and depress the tongue

Question 28

What are the extrinsic tongue muscles?

Answer 28

- palatoglossus - styloglossus - hyoglossus - genioglossus

Question 29

Describe the muscles of the tongue.

Answer 29

- 4 intrinsic and 4 extrinsic - all paired - paired muscles are separated by sagittal septum (continuous with lingual aperoneurosis) - intrinsic muscles are entirely within tongue, do not attach to bone - extrinsic muscles originate from outwith the tongue

Question 30

What is the origin and insertion of genioglossus?

Answer 30

Origin - superior mental spines of mandible Insertion - inferior fibres attach to hyoid bone, superior fibres blend with intrinsic muscles of tongue

Question 31

What is the origin and insertion of hyoglossus?

Answer 31

Origin - greater horn of hyoid bone Insertion - fibres blend with intrinsic muscles on lateral aspects

Question 32

What is the origin and insertion of palatoglossus?

Answer 32

Origin - palatine aponeurosis Insertion - fibres blend with intrinsic muscles on lateral surface

Question 33

What is the origin and insertion of styloglossus?

Answer 33

Origin - styloid process of temporal bone Insertion - fibres blend with intrinsic muscles and superior fibres of hyoglossus

Question 34

What is the function of genioglossus?

Answer 34

Protruding the tongue

Question 35

What is the function of hyoglossus?

Answer 35

Depresses sides of the tongue

Question 36

What is the function of styloglossus?

Answer 36

Elevating and retracting tongue

Question 37

What is the function of palatoglossus?

Answer 37

- depresses soft palate - elevate posterior tongue

Question 38

What neurovascular structures surround the muscles of the tongue?

Answer 38

- lingual artery enters tongue between hyoglossus and genioglossus - hypoglossal and lingual nerve enter tongue o the internal surface of the hyoglossus

Question 39

What is the motor innervation of the tongue?

Answer 39

- all muscles are supplied by hypoglossal nerve - except palatoglossus by vagus nerve

Question 40

What is the general sensation innervation of the tongue?

Answer 40

Anterior 2/3 - CN V3 Posterior 1/3 - glossopharyngeal nerve

Question 41

What is the special sensation innervation of the tongue?

Answer 41

Anterior 2/3 - facial nerve via chorda tympani Posterior 1/3 (and valate papillae) - glossopharyngeal nerve

Question 42

What nerve supplies parasympathetic secreto-motor innervation to the tongue?

Answer 42

Vagus nerve to the serous glands of the tongue

Question 43

What is the blood supply of the tongue?

Answer 43

Lingual artery from the ECA

Question 44

What is the venous drainage of the tongue?

Answer 44

Deep lingual and dorsal lingual veins drain the tongue, beginning at the apex, draining into the IJV