Lecture 11 = Oral Cavity

Question 1

What is the oral cavity?

Answer 1

• Oral cavity is from the lips back to the palatoglossal folds
• the posterior extent of oral cavity is called the oropharynx
• the oral cavity has 2 regions:
  
  • the oral vestibule which is in-between the buccal surface laterally and the lips anteriorly and the posterior regions are the alveolar ridges/teeth
  • the oral cavity proper is everything between the teeth, laterally, the palate superiorly and the tongue and sublingual area as the roof of the mouth

Question 2

What are the arteries serving the oral (buccal) cavity?

Answer 2

• facial a. supplies most of the superficial structures?
• arteries serving this area are the labial a. and have superior and inferior branches which anastomose on either side as branches of facial a.
• these arteries are found deep to orbiculares oris m. and usually close to inferior extent of superior lip and superior extent of inferior lip so close to margins of lips called the vermillion.
• the vermilion border makes the line between the skin and the red of the lips
• we have the border because the submucosal papilla brings the vessels (submucosal aa.( close to the surface

Question 3

What encompasses the oral cavity?

Answer 3

• roof: hard palate and soft palate
  
  • palatine raphe, uvula
• floor: Tongue (dorsum of tongue) and sublingual region
• anterior/lateral walls: teeth and gums (gingiva)
• posterior/lateral walls: palatoglossal arches/folds
  
  • this is the epithelial overlying the palatoglossal m.
  • everything past the first arch is the oropharynx
  • we can see the palatine tonsils so they are in the oropharynx
• the oral cavity is continuous with the oropharynx
• the hard palate and soft palate are the roof and the soft palate is a very mobile flap. This is key for swallowing. If this didn’t move, then we couldn’t breath efficiently and we would have food in the nasal cavity all of the time b/c the epithelium is different in the nasal cavities and oral cavities
• the ciliated psudostratified columnar epithelium in the nasal cavity can’t handle the pH changes of the food we eat.
• the oral cavity has stratified squamous epithelium which can handle food changes.
• oral cavity proper is inside the teeth anterior and laterally.

Question 4

What are the soft and hard palate?

Answer 4

• hard palate is the anterior 2/3
• soft palate is the posterior 1/3
• the shape of the hard and soft palate are different
• raphe continues down hard palate but is not the same in the soft palate because this is where we have the muscles coming together
  
  • soft palate is created by muscles that combine in this area
• hard palate is supported by bony structure and soft palate is supported by muscle
• portion of soft palate hanging down back of the throat is called the uvula and is comprised of uvula m.

Question 5

What is the soft palate?

Answer 5

• lots of palatine glands comprise the mucosa
• lots of tissue cross the midline
• muscles are interdigitating in the midline - thats how the soft palate
• palatopharyngeal m. underlies the pharyngeal arch/fold and is posterior to palatine tonsil
• underlying the mucosa are lots of palatine glands/accessory which are prominent in both hard and soft palate
• aponeurosis means tendinous sheath
• the tendinous sheath here comes from the tensor veli palatini m.
  
  • it is a vertically oriented muscle that has a tendon that hooks underneath the pterygoid hamulus and the and the tendon fibers mix with the muscle fibers across the soft palate
• if give this tendon tension, then a muscle can do stretch and act.

Question 6

What is the tensor veil palatini m.?

Answer 6

• is more lateral in position then the other mm.
• can always see the tendinous fibers on the soft palate in association with the pterygoid hamulus
• tensor gives us tension to create a hold and levator holds it
• the tensor is attached to the Eustachian tube and levator runs along the same axis of it
• the levator opens the Eustachian tube which allows the air to equilibrate along the sides

Question 7

What is the levator veil palatini m.?

Answer 7

• located just posteromedial to tensor veli palatini m.
• inner: CN X vagus via pharyngeal branch to pharyngeal plexus
• action: only muscle to elevate the soft palate about the natural position and retracts it
• levator is tested by having the patient say “ah”
  
  • if the muscle on each side is functioning normally, the palate elevates evenly in the midline
  • if one side is not functioning, the palate deviates away from the abnormal side
• is medial to the medial pterygoid m. and lateral to lateral to lateral pterygoid m.
• tensor gives us tension to create a hold and levator holds it
• the tensor is attached to the Eustachian tube and levator runs along the same axis of it
• the levator opens the Eustachian tube which allows the air to equilibrate along the sides

Question 8

What is the vascular supply of the palate?

Answer 8

I. descending palatine a.

• gives rise to greater and lesser palatine aa.
• descends thru palatine canal
  i. greater palatine a.
  
  • supplies anterior palate
  • passes thru greater palatine foramen
    ii. lesser palatine a.
  • supplies posterior palate
  • passes thru lesser palatine foramen
• all of the venous drainage will be via the pterygoid and pharyngeal plexuses

Question 9

What are the palatine arteries?

Answer 9

• lesser palatine a.
• greater palatine a.
• ascending palatine a.
• palatine branch of ascending pharyngeal a.

Question 10

What are the palatine nerves?

Answer 10

• nasopalatine n.
• lesser palatine n.
• greater palatine n.
  
  • these all 3 serve general sensory to the hard and soft palate and all have parasympathetic and sympathetic innervation
• the preganglionic sympathetic come from T1 lateral horn and travel up the sympathetic trunk horn and synapse at superior cervical ganglion. Those fibers jump on internal carotid plexuses and come off as the deep petrosal which gives rise to the sympathetic innervation to the nerve of the nerve of pterygoid canal and this is how you get sympathetic innvervation of V2 because of the mucosa membrane
  
  • need sympathetic innervation because of the blood vessels
  • anywhere you have blood vessels, you’ll have sympathetic innervation
• Parasympathetics come from facial - they come down the greater petrosal n (pregang parasympathetic and special sensory [taste]) and join with deep petrosal n. = these two joining make the vidian n. and the presynaptic parasympathetic from CN 7 synapses on ptergopalatine ganglion and the parasympathetics move around the V2

Question 11

What is the motor innervation of the soft palate?

Answer 11

I. mandibular n. (Cn V3)
- supplies tensor veli palatini m. (b/c of the embryological origin - first pharyngeal arch)
II. vagus n. (CN X)
- supplies levator veli palatini mm., palatoglossus mm., palatopharyngeus mm., musculus uvulae, salpingopharyngeus mm. (via the pharyngeal plexus)
**most of palatal mm. are innervated by CN 10

Question 12

What are the arterial supply of the palatine tonsils?

Answer 12

• tonsillar branch of lesser palatine a.
• tonsillar branch of ascending pharyngeal a.
• tonsillar branch of ascending palatine a.
• tonsillar branch of facial a.
• tonsillar branch of dorsal lingual a.
• all on tonsillar bed (palatalglossal m. and palatal pharyngal mm.)

Question 13

What is tonsillectomy?

Answer 13

• palatine tonsils may be removed
• heavy bleeding may occur from aa.
• bleeding from paratonsillar v. also common
  
  • venous drainaige from tonsillar bed region
• CN IX lies on lateral pharyngeal wall
  
  • vulnerable to injury because lateral wall is thin
• venous drainage is to the pterygoid plexus and facial v.
• when you et older, the lymphoid tissue swells down

Question 14

what are the sublingual features of the oral cavity?

Answer 14

• can see deep lingual vv. though the translucent layer on surface of the tongue
• the sublingual folds are filled with the sublingual ducts

*submandibular glands use V3 branches

Question 15

What is the lingual n?

Answer 15

• lingual n. goes to anterior 2/3 of tongue - hard palate for general and special sensory
• it come down and crosses underneath the duct and comes up medially to the duct - cross the wharton’s duct and crosses it twice .
• it’s branch of CN V3
• emerges between lateral and medial pterygoid mm.

Question 16

What is the submandibular ganglion?

Answer 16

• it’s at the level of the 3rd molar
• suspended from lingual n. by 2 or more short nerve branches
• relays p-symp fibers from chorda tympani (CN VII)
• these fibers travel to submandibular and sublingual glands
• symp. fibers to glands are from external carotid plexus
• special sensory taste is for anterior 2/3 of tongue - hard palate
• if have lesion in nerve after chorda tympani is joined with the lingual n. - you lose taste, general sensory to hard palate and parasympathetic to submandibular and sublingual glands

Question 17

What’s the hypoglossal n.?

Answer 17

• deep to posterior belly of digastric m. and stylohyoid m.
• runs anterior between submandibular gland and hypoglossus m.
• inferior to lingual n.
• superior to mylohyoid m.
• ends in posterior tongue to provide motor innervation

Question 18

What’s the glossopharyngeal n.?

Answer 18

• runs lateral to stylopharyngeus m. to enter pharynx
• between superior and middle constrictor mm.
• continues anteriorly thru tonsillar region
• ends in posterior tongue to receive sensory innervation

Question 19

What are the muscles of the tongue?

Answer 19

I. palatoglossus m.
II. styloglossus m.
- styloid process to base of tongue
III. hypoglossus m. (rectangular muscle)
- hyoid bone to tongue
IV: genioglossus m. (most of the bulk of the mm of the tongue)
- genoid tubercle to mandible to tongue
- make sure to differentiate this from the mylohyoid and geniohyoid mm.
V: Intrinsic mm.
- vertical, transverse and long fibers
- are also innverated by CN 12

*except # 5, everything else are extrinsic mm.

Question 20

What is genioglossus m.?

Answer 20

• paired mm fused in midline that serves to protrude tongue
• unilateral paralysis of CN XII affects straight protrusion
  
  • intact side protrudes more than affected side
  • results in deviation of tongue toward paralyzed side
• bilateral paralysis results in inability to protrude tongue
  
  • tongue falls back and may occlude airway (suffocation)

Question 21

What is the arterial supply of the oral cavity?

Answer 21

I. facial a. - supplies most of superficial structures
II. maxillary a. - supplies buccinator m.
II. lingual a. - supplies most of deeper structures
- 3 branches to tongue region
- dorsal lingual a., deep lingual a., and sublingual a.
- often have 2 veins for each artery
*accompanying provide venous drainage to IJV
*both are branches from external carotid

Question 22

What is the supplies special sensory to the tongue?

Answer 22

I. chorda tympani n. (CN VII)
 - taste of anterior 2/3
 - fibers travel with lingual n.
II. glossopharyngeal n. (CN IX)
 - taste from posterior 1/3 tongue
III. Vagus (CN X)
 - taste from tooth of tongue and epiglottis 
 - via internal branch of superior laryngeal nerve

Question 23

What supplies general sensory to the tongue?

Answer 23

I. Lingual n. (CN V3)
 - sensory of anterior 2/3 tongue
II. glossopharyngeal n. (CN IX) 
 - sensory of posterior 1/3 of tongue 
III. vagus (CN X)
 - sensory of root of tongue and epiglottis

Question 24

what are the arterial supply of the maxilla and mandible?

Answer 24

Anterior superior alveolar a. - branch of infraorbital a.
- maxilla incisors/canine
Middle superior alveolar a. - branch of infraorbital a.
- maxilla premolars
Posterior superior alveolar a. - branch of maxillary a.
- maxillary molars
inferior alveolar a. - branch of maxillary a.
- mandibular premolars/molars
- branch off of this called incisive a goes to mand. incisors
**arterial supply corresponds to the nerve supply of teeth
** all of the veins drain back to the pterygoid plexus which ends up draining to the EJ and IJ