Oral Cavity And Its Boundaries

Question 1

What does the oral cavity divide into?

Answer 1

Vestibule and oral cavity proper

Question 2

Where is the vestibule?

Answer 2

Between teeth and gums internally, lips and cheeks laterally

Question 3

Where is oral cavity proper?

Answer 3

Bounded anteriorly and laterally by dental arcades. Roof is hard palate and floor is muscles of the floor of the mouth.

Question 4

Where does the blood supply of the teeth drain?

Answer 4

Teeth drain into the pterygoid venous plexus, draining into maxillary vein into the retromandibular vein. Possibility that they can drain into emissary veins and then into the cavernous sinus.

Question 5

Blood supply to the teeth

Answer 5

Maxillary artery
Inferior alveolar artery and vein through the mandibular canal
Posterior and anterior superior alveolar artery and vein

Question 6

Nerve supply to lower arcade of teeth

Answer 6

Mandibular division gives anterior and posterior divisions:
Posterior division will give inferior alveolar never through mandibular canal which will travel through mandibular turning into the mental nerve to give sensation to inferior 1/3 of teeth

Question 7

Nerve supply to upper arcade of the teeth

Answer 7

Maxillary division
Infraorbital nerve through infraorbital groove in the floor of the orbit. It goes anteriorly in the infraorbital canal opening into the Infraorbital foramen, giving 2 branches - the anterior and middle superior alveolar nerves which innervate the upper teeth.

Question 8

What is the hard palate made from and what does it separate?

Answer 8

Separates oral from nasal cavity. Made mainly of the palatine process of maxilla and horizontal plate of palatine bone.

Question 9

Route of the maxillary nerve to the palate

Answer 9

Maxillary nerve enters the pterygopalatine fossa through the foramen rotundum, giving some branches here. The pterygopalatine fossa opens inferiorly to the greater and lesser palatine canals which travel inferiorly to open into the greater and lesser palatine foramens.

Question 10

What goes through the greater palatine foramen?

Answer 10

Greater palatine artery (branch of the descending palatine artery which comes off the 3rd part of maxillary artery) goes through the greater palatine foramen

Question 11

Which foramen does the nasopalatine nerve go through and what fibres does it carry?

Answer 11

Nasopalatine nerve is a branch of maxillary nerve. Carries sensory fibres and parasympathetic fibres from the pterygopalatine ganglion. Exits through the incisive foramen.

Question 12

What exits through the lesser palatine foramen?

Answer 12

Lesser palatine artery (branch of descending palatine which is branch of maxillary artery)
Lesser palatine nerve (branch of maxillary nerve which originates in pterygopalatine fossa)

Question 13

What does the lesser palatine nerve supply?

Answer 13

Gives sensory information to the soft palate.

Question 14

What nerve communicates with the pterygopalatine ganglion to innervate small salivary glands?

Answer 14

Greater petrosal nerve branches off the facial nerve. It is the preganglionic neuron that communicates with the pterygopalatine ganglion. Postganglionic parasympathetic and sympathetic fibres will join branches of the maxillary nerve and hitchhike to get to the palate to innervate e.g., smaller salivary glands.

Question 15

What are the muscles of the soft palate made of and why?

Answer 15

Innervation by the pharyngeal plexus of the vagus since they all originate from the 4th pharyngeal arch, except tensor veli palatini which originates from the 1st arch with the muscles of mastication, being innervated by the medial pterygoid nerve of CNV3.

Question 16

Where are the palatine tonsils found?

Answer 16

The palatoglossus and palatopharyngeus muscles are covered by mucosa, forming arches. The most anterior one is palatoglossus and most posterior is palatopharyngeus arch. Between these 2 arches is the palatine tonsils.

Question 17

What supplies sensory innervation to the anterior 2/3 of the tongue?

Answer 17

General sensory = lingual nerve (branch of CNV3)
Special sensory (taste) = chorda tympani (branch of CNVII)

Question 18

What supplies sensory innervation to the posterior 1/3 of the tongue?

Answer 18

General and special sensory = glossopharyngeal

Question 19

What supplies motor innervation to the tongue?

Answer 19

All intrinsic and extrinsic muscles of the tongue are supplies by the hypoglossal nerve CNXII
Palatoglossus is a muscle of the soft palate so is innervated by the vagus CNX

Question 20

What are the extrinsic muscles of the tongue?

Answer 20

Genioglossus, styloglossus, hyoglossus

Question 21

What are the intrinsic muscles of the tongue?

Answer 21

Superior longitudinal
Vertical
Transverse
Inferior longitudinal

Question 22

What does the parotid duct pierce and where does it enter?

Answer 22

Parotid duct goes from gland and pierces the buccinator muscle, opening in the vestibule just opposite the upper second molar.

Question 23

What is motor supply to parotid gland from?

Answer 23

Parasympathetic motor supply from glossopharyngeal nerve CNIX

Question 24

Motor supply to submandibular and sublingual glands?

Answer 24

Parasympathetic motor supply from the facial nerve CNVII

Question 25

Where does the submandibular duct pass?

Answer 25

Between the mylohyoid and hyoglossus muscles

Question 26

Where do the sublingual ducts open?

Answer 26

Just lateral to the caruncles of submandibular glands - beneath the tongue.

Question 27

Where must the needle go to anaesthetise the inferior alveolar nerve?

Answer 27

In the pterygomandiblar space