Oral cavity Flashcards

1
Q

The Oral Region includes

A
A.	Oral cavity
B.	Cheeks and lips
C.	Teeth and gingivae
D.	Tongue
E.	Tonsils
F.	Salivary glands
G.	Palate
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2
Q

Oral Cavity

A

A. Consists of oral cavity proper and vestibule.

B. The oral cavity is the proximal-most portion of the GI tract.

C. It is the space bounded by the lips/cheeks and teeth; posteriorly by the oropharynx; superiorly by the palate.

D. Contains the teeth, tongue, gingivae, and openings of all three salivary glands.

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3
Q

vestibule of the oral cavity

A
  1. Space between the lips/cheeks and teeth.
  2. Opens externally at the oral fissure between lips.
  3. Muscles of facial expression control shape/size of oral fissure.
  4. Parotid duct opens into the vestibule opposite the upper 2nd molar.
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4
Q

Boundaries of Oral Cavity Proper

A
  1. Lateral/anterior – teeth gums
  2. Superior – hard/soft palate
  3. Inferior – floor of mouth
  4. Posterior – fauces
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5
Q

Lips: description, innervation, lymphatic drainage

A

Musculofasical skin folds (upper, lower).

Innervation

  1. Upper lip – V2 via infraorbital branches
  2. Lower lip – V3 via mental and buccal branches

Lymphatic drainage

  1. Submental lymph nodes – medial part of lower lip
  2. Submandibular lymph nodes – all other regions
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6
Q

lips: structure

A
  1. Externally – covered by thin skin
  2. Internally – covered by mucus membrane.
  3. Muscles of facial expression allow for mobility to control size, shape of oral fissure.
    a. Orbicularis oris – closes lips/mouth
    b. Levator labii superioris – elevates upper lip
    c. Levator anguli oris – elevates upper lip; widens mouth
    d. Zygomaticus major and minor – elevates upper lip; main smile muscles
    e. Risorius – stretches lips laterally; wide smile
    f. Levator labii superioris alaeque nasi – elevates upper lip; flares nostrils
    g. Depressor anguli oris – depresses lower lip; frown
    h. Depressor labii inferioris – depresses lower lip; frown, pout
    i. Mentalis – protrudes lower lip
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7
Q

Teeth and Gingivae: function, numbers

A

A. Function – mastication, articulation

B. 32 permanent teeth; 16 deciduous (baby teeth)

  1. Incisors (4), canine (2), premolars (4), molars (6)
  2. Typically appear around 6-8 years of age
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8
Q

Gingivae

A

mucus membrane and fibrous tissue attached to the alveolar processes of the mandible and maxilla bones; also attached to neck of teeth.

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9
Q

Innervation of teeth

A
  1. Maxillary teeth – superior alveolar branches of V2

2. Mandibular teeth – inferior alveolar branches of V3

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10
Q

Innervation of gingivae

A
  1. Maxillary gingivae
    a. Palatine portion
  2. Nasopalatine n (V2)
  3. Greater palatine n (V2)
    b. Vestibular portion
  4. Superior alveolar branches of V2
  5. Mandibular teeth – inferior alveolar branches of V3
    a. Internal portion
  6. Lingual n (V3)
    b. External portion
  7. Buccal n (V3)
  8. Inferior alveolar n, mental branch (V3)
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11
Q

lymphatic drainage of teeth and gingivae

A
  1. Most lymph drainage is to submandibular lymph nodes
  2. Exception: mandibular incisors drain to submental lymph nodes.
  3. Exception: 3rd maxillary molars drain directly to superior deep cervical lymph nodes.
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12
Q

Tongue: defn, features, external structures

A

B. Muscular, mobile organ involved in mastication, swallowing, articulation, and taste.

C. Features

  1. Body
    a. Anterior 2/3rds of tongue; ends anteriorly at apex
    b. Mobile
  2. Root
    a. Posterior 1/3 of tongue
    b. Anchored to mandible, hyoid, and styloid process.
  3. Epiglottic portion

D. External structures

  1. Terminal sulcus
    a. V-shaped groove on dorsum of tongue
    b. Separates root from body
    c. Represents embryonic site of oropharyngeal membrane.
  2. Foramen cecum – remnant of thyroglossal duct
  3. Median sulcus
  4. Median and lateral glossoepiglottic folds
  5. Epiglottic valleculae
  6. Papillae – vallate, filiform (no taste buds), fungiform, foliate
  7. Lingual tonsils
  8. Frenulum of the tongue
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13
Q

Muscles of Tongue

A
  1. Intrinsic muscles (alter the shape of the tongue)
    a. Longitudinal (shorten; retract tongue; also can curl tongue)
    b. Vertical (flatten; broaden tongue)
    c. Transverse (narrow; elongate tongue)

Extrinsic muscles (alter the position of the tongue)

Genioglossus
hyoglossus,
styloglossus
palatoglossus

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14
Q

Genioglossus

A
  1. Origin – mental spines of mandible
  2. Insertion – dorsum of tongue; from apex to hyoid
  3. Innervation – hypoglossal n.
  4. Function – acting bilaterally - protrudes tongue; acting unilaterally – pushes tongue to opposite side
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15
Q

Hyoglossus

A
  1. Origin – Hyoid bone
  2. Insertion – inferolateral side of tongue
  3. Innervation – hypoglossal n.
  4. Function – retracts; depresses tongue
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16
Q

Styloglossus

A
  1. Origin – styloid process
  2. Insertion – superolateral side of tongue
  3. Innervation – hypoglossal n.
  4. Function – retracts; elevates tongue
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17
Q

Palatoglossus

A
  1. Origin – soft palate
  2. Insertion – tongue
  3. Innervation – vagus n
  4. Function – pulls tongue and soft palate together during swallowing
18
Q

Tongue innervation: motor

A
  1. Hypoglossal nerve – GSE to all muscles except palatoglossus
  2. Vagus nerve – SVE to palatoglossus
19
Q
  1. CLINICAL CORRELATION – Hypoglossal Nerve Lesion.
A

When patient is asked to protrude tongue, tongue will deviate toward affected (paralyzed) side because functioning genioglossus muscle pushes tongue contralaterally.

20
Q

tongue innervation: sensory

A
  1. Anterior 2/3
    a. General sensory (GSA) – lingual branch of V3
    b. Taste (SVA) – Facial nerve via chorda tympani
  2. Posterior 1/3
    a. General sensory (GVA) – Glossopharyngeal n.
    b. Taste (SVA) – Glossopharyngeal n.
  3. Epiglottic region
    a. General sensory (GVA) – internal laryngeal branch of vagus nerve
    b. Taste (SVA) – superior laryngeal branch of vagus nerve
21
Q

tongue blood supply

A
  1. Lingual artery – branch of external carotid artery
    a. Dorsal lingual a. (posterior tongue/palatine tonsil)
    b. Sublingual a. (floor of mouth)
    c. Deep lingual a. (anterior tongue)
  2. Lingual veins – drain tongue and floor of oral cavity directly to internal jugular vein.
  3. Venae comitantes hypoglossi – drain floor of oral cavity and parallel course of hypoglossal nerve to end in the common facial vein.
22
Q

tongue lymphatic drainage

A

I. Lymphatic drainage

  1. Posterior 1/3 – superior deep cervical lymph nodes (bilateral)
  2. Anterior 2/3
    a. Lateral sides – submandibular nodes (ipsilateral)
    b. Middle – inferior deep cervical nodes (bilateral)
    c. Apex – submental nodes (the medial portion draining bilaterally)
23
Q

tonsils

A

A. Masses of lymphoid tissue situated in the nasopharynx, oropharynx, and oral cavity.

  1. Lingual tonsils – located deep to mucosa of posterior 1/3 of tongue.
  2. Pharyngeal tonsils – located within pharyngeal recess of nasopharynx.
  3. Palatine tonsils – located at opening of oropharynx; between palatoglossal and palatopharyngeal arches.
  4. Tubal – located at opening of auditory tube.

B. These 4 groups form a defensive ring of lymphoid tissue referred to as the pharyngeal lymphoid ring or Waldeyer’s ring.

C. CLINICAL CORRELATION – lymph nodes can become englarged and occlude surrounding structures (fauces, opening to auditory tube; nasopharynx). When pharyngeal tonsils are inflamed they are referred to as adenoids.

24
Q

Salivary glands

A

A. Secrete salivary fluid into oral cavity which functions to: begin process of digestion, lubricate food, prevent tooth decay, moisten oral cavity.

B. Parotid glands (see face, scalp and parotid lecture)

C. Sublingual glands

  1. Lie in floor of oral cavity; covered with oral mucosa.
  2. Forms sublingual fold on floor of mouth.
  3. Open into oral cavity via several small ducts on sublingual fold.

D. Submandibular glands

  1. Superficial portion lies within submandibular triangle of neck; deep to mandible; superficial to mylohyoid muscle.
  2. Deep portion of gland wraps around the posterior border of the mylohyoid to pass between it and the hyoglossus muscle.
  3. Submandibular (Wharton’s) duct courses anteriorly from deep part of gland (between mylohyoid and hyoglossus) to open in floor of the mouth on the sublingual caruncle.
  4. NOTE: The lingual nerve wraps around the submandibular duct as they course forward.
25
Q

Innervation of Parotid Gland: parasympathetic

A

a. Preganglionic (glossopharyngeal nerve)
1. Location of cell bodies – salivatory nucleus within brainstem
2. Preganglionic fibers travel with the glossopharyngeal nerve (CN IX).
3. CN IX exits at jugular foramen and immediately gives a tympanic branch.
4. The tympanic nerve then enters the middle ear via the tympanic canaliculus.
5. Travels through the middle ear and then reforms as the lesser petrosal nerve.
6. Lesser petrosal nerve exits middle ear via hiatus for the lesser petrosal nerve; nerve is now in the middle cranial fossa and exits via the foramen ovale.
7. Lesser petrosal n is now in infratemporal fossa and synapses in otic ganglion.
b. Postganglionic (distribute with V3)
1. Location of cell bodies – otic ganglion
2. Postganglionic fibers travel with the auriculotemporal branch of V3.
c. Function: secretomotor; stimulates gland secretion

26
Q

innervation of parotid gland: sympathetic

A

a. Preganglionic cell bodies located in the spinal cord at levels T1-T4.
b. Postganglionic cell bodies located in superior cervical sympathetic ganglion.
c. Postganglionic fibers travel with external carotid nerve to parotid tissue.
d. Function: vasomotor

27
Q

Innervation of sublingual and submandibular glands: parasympathetic

A

a. Preganglionic (facial nerve)
1. Location of cell bodies – salivatory nucleus within brainstem
2. Preganglionic fibers travel with the facial nerve (CN VII).
3. CN VII courses along the posterior wall of the middle ear and gives rise to the chorda tympani n.
4. The chorda tympani n. then exits the middle ear through the petrotympanic hiatus to enter the infratemporal fossa.
5. Here, chorda tympani joins the lingual nerve.
6. The chorda tympani portion of the lingual nerve synapses in the submandibular ganglion.
b. Postganglionic
1. Location of cell bodies – submandibular ganglion
2. Postganglionic fibers travel with the lingual branch of V3.
c. Function: secretomotor; stimulate salivation

28
Q

Submandibular ganglion

A

a. Ganglion suspended from lingual nerve within posterior floor of oral cavity.
b. Contains the cell bodies of postganglionic parasympathetic fibers.
c. Provides innervation for the submandibular and sublingual glands

29
Q

Innervation of sublingual and submandibular glands: sympathetic

A

a. Preganglionic cell bodies located in the spinal cord at levels T1-T4.
b. Postganglionic cell bodies located in superior cervical sympathetic ganglion.
c. Postganglionic fibers travel with external carotid nerve to the gland tissue.
d. Function: vasomotor

30
Q

Submandibular region boundaries

A
  1. Inferior – anterior and posterior bellies of digastric muscles
  2. Superior – mandible
  3. Roof – cervical investing fascia
  4. Floor – mylohyoid muscle
31
Q

submandibular region contents

A
  1. Submandibular gland
  2. Facial artery
  3. CN XII
  4. Suprahyoid muscles
32
Q

Suprahyoid muscles

A

digastric
stylohyoid
mylohyoid
geniohyoid

33
Q

Digastric

A
  1. Origin – anterior belly (digastric fossa of mandible)
    – posterior belly (mastoid notch of temporal bone)
  2. Insertion - hyoid
  3. Innervation – anterior belly (V3); posterior belly (CN VII)
  4. Function – depresses mandible; elevates hyoid
34
Q

Stylohyoid

A
  1. Origin – styloid process
  2. Insertion – hyoid
  3. Innervation – CN VII
  4. Function – elevates and retracts hyoid
35
Q

Mylohyoid

A
  1. Origin – mylohyoid line of mandible
  2. Insertion – midline raphe and hyoid
  3. Innervation – mylohyoid branch of V3
  4. Function – elevates hyoid and floor of mouth; assists with opening mouth
36
Q

Geniohyoid

A
  1. Origin – mental spines of mandible
  2. Insertion – hyoid
  3. Innervation – C1 via hypoglossal
  4. Function – elevates hyoid; when hyoid fixed, opens mouth
37
Q

Vasculature in submandibular and oral regions

A
  1. Lingual artery – branch of external carotid artery
    a. Dorsal lingual a. (posterior tongue)
    b. Sublingual a. (floor of mouth)
    c. Deep lingual a. (anterior tongue)
  2. Lingual veins – drain directly to internal jugular vein
  3. Venae comitantes hypoglossi – veins which parallel course of hypoglossal nerve and end in the common facial vein.
38
Q

CLINICAL CORRELATION – Sublingual Absorption of Drugs

A

certain drugs (such as nitroglycerin) need rapid absorption. Because the lingual veins drain directly to the IJV, drugs can be placed in the sublingual region (below the tongue on floor of mouth) and rapidly absorbed into the bloodstream.

39
Q

Nerves to the oral cavity: lingual nerve

A

a. Branch of V3
b. Enters oral cavity posteriorly from infratemporal fossa.
c. Courses through paralingual space (between hyoglossus and mylohyoid mm.)
d. Wraps around submandibular duct in course.
e. Pierces tongue laterally.
f. Provides GSA to floor of mouth and anterior 2/3 of tongue
g. Distributes:
1. SVA – via chorda tympani
2. GVE-P – via chorda tympani
3. Chorda tympani (CN VII) nerve
a. Chorda tympani is a branch of CN VII given of within middle ear.
b. Chorda tympani n exits middle ear via petrotympanic fissure to enter infratemporal fossa.
c. Here, it merges with the lingual n (V3) to travel to the oral cavity.
d. Carries
1. SVA to anterior 2/3rds of tongue
2. GVE-P (parasympathetic fibers) to submandibular ganglion to be distributed to the submandibular and sublingual glands.

40
Q

nerves to oral cavity: hypoglossal

A
  1. Enters oral cavity from submandibular region.
  2. After passing lateral to the occipital artery, the hypoglossal nerve then enters the paralingual space.
  3. Provides:
    a. GSE – extrinsic tongue muscles (except palatoglossus)
    b. GSE – intrinsic tongue muscles
41
Q

nerves to oral cavity: glossopharyngeal nerve

A
  1. Enters oral cavity posteriorly from pharyngeal region.
  2. After passing in between the superior and middle constrictor muscles, CN IX travels forward to pierce the tongue posteriorly.
  3. Provides:
    a. GVA – posterior 1/3 of tongue
    b. SVA – posterior 1/3 of tongue
42
Q

nerves to oral cavity: vagus

A
  1. Internal branch of superior laryngeal nerve will enters oral cavity posteriorly from pharyngeal region.
  2. After passing in between the middle and inferior constrictors muscles, the internal laryngeal nerve will ascend to supply the epiglottic region of the tongue
  3. Provides:
    a. GVA – epiglottic region of tongue
    b. SVA – epiglottic region of tongue