Oral Cavity: Mon., Oct 9
Terms
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- Teeth:
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*32 in adult
*20 "milk teeth" or deciduous teeth
*medial and lateral incisors
*caninie
*2 premolars
*3 molars - Tooth Innervation:
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1. mandibular teeth: inferior alveolar nerve (V3)
2. maxillary teeth: posterior superior alveolar (V2), middle superior alveolar (off infraorbital (V2)), anterior superior alveolar (infraorbital) - Hard Palate:
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*made up of palatine process of maxilla more anteriorly and horizontal plate of palatine more posteriorly
*intermaxillary suture-separates 2 palatine shelves
*palatomaxillary suture-runs trasversely
*greater palatine foramen-located around 3rd molar by edges of maxilla and palatine
*lesser palatine foramen (posterior to greater)
*incisive canal-nasopalatine nerve extis to pass posteriorly and connect with greater palatine nerve - Undissected Oral Cavity:
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*uvula-part of soft palate
*palatoglossal and palatopharyngeal arches and respective folds
*palatoglossal and palatopharyngeal muscles deep to arches
*palatine tonsils-lie in between arches
*tongue-posterior portion less mobile and named "root"; anterior surface more mobile and is primarily dorsum of tongue - Tongue Elevated:
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1. vestibule-area between lips and teeth
2. frenulum-small band of connective tissue in midline of underside of tongue
**undersurface of tongue, mucosa is very thin as to see blood vessels
3. sublingual caruncle-small folds on either side of base of frenulum with openings of submandibular duct - Floor of Oral Cavity: inferior view
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1. mylohyoid-main contributor;
2. geniohyoid-superior to mylohyoid; attaches to inferior genial spine of mandible - Floor of Oral Cavity: superior view
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1. genioglossus-tongue muscle: attaches to superior genial spine of mandible
**CC: while unconscious, tongue will fall back and occlude airway; pull mandible anteriorly to use genioglossus to pull tongue forward
2. hyoglossus-extrinsic
3. inferior alveolar and lingual nerve-both from V3
*inferior alveolar nerve runs inferiorly to pass into mandibular foramen
*lingual nerve travels lateral then medial to submandibular duct - Path of Lingual nerve:
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*branch of V3
*carries afferent fibers from anterior 2/3 of tongue for "touch" and sensation
*efferent fibers from chorda tympani nerve (off facial) that enter the lingual nerve; these fibers synapse in submandibular ganglion
*submandibular ganglion rests on lateral surface of hyglossus
*linguan nerve will cross over lateral surface of submandibular duct, then inferior, forming a hammock, and then runs medially to duct (**crosses duct twice) - Lateral and Coronal sections of cavity: Buccinator
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1. buccinator-pierced by parotid duct to go to oral cavity just adjacent to upper 2nd molar
*innervated by CNVII but not muscle of facial expression but described as "accessory mastication muscle"
*keeps bolus of food out of vestibule
2. buccal fat pad (suctorial)-associated just anterior to anterior edge of buccinator
*deficiency in fat pads results in dimples
**CC: facial nerve palsy-food gets caught in vestibule - Fauces
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1. throat:
*posterior border of oral cavity
*between right left palatal arches
*another name for arches are "pillar of pharynx"
*line of demarcation on tongue between root (oropharynx) and more anterior part - Lips:
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*allows for more effective speech, grasping objects, and osculation (kissing)
*innervated by superior labial nerve (infraorbital) and inferior labial nerve (mental nerve) - Philtrun
- **small furrow in midline between the columella and upper edge of lip
- Salivary Glands:
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1. 3 major glands:
a) Parotid-largest
b) submandibular
c) sublingual-smallest
*make ~pint of saliva/day
2. parasympathetic innervation: a)facial nerve (via chorda tympani/lingual) for submandibular and sublingual
b)glossopharyngeal (CNIX)-via otic ganglion for parotid
3. Accessory Salivary:
*can be found just behind lips, adjacent to buccinator, on palate, around tonsils, around tongue, etc. - Medial view of Mandible:
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1. gingival: connective tissue lining that helps anchor teeth
2. submandibular gland forms a C shape around mylohyoid, dividing into superficial and deep portions
*deep portion is smaller and where duct arises from and runs anteriomedially
3. sublingual gland: has small ductules that drain either directly into oral cavity or in to submandibular duct
**CC: lingual nerve in close proximity to 3rd molar; during extraction, roots could torque nerve, resulting in loss of sensation to anterior 2/3 of tongue ipsilaterally - Soft Palate:
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1. levator veli palatini-attached to posterior nasal spine (via palatine aponeurosis)
2. tensor veli palatini-wraps around hook of pterygoid hamulus
*both attach to cartilaginous portion of Eustachian tube
**Sensory innervation to hard/soft palates: greater and lesser palatine
**Motor: TVP-mostly V3; remaining muscle of soft palate via pharyngeal plexus (CNX) - Extrinsic Tongue Muscles:
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1. styloglossus: arise from styloid process and stylohyoid ligament
*elevates and retracts protruded tongue
2. hyoglossus: arise from hyoid
*pulls tongue down flat in cavity
3. genioglossus: forms "meat" of tongue; arises from superior genial spine and runs into tongue
*helps protrude tongue
4. intrinsic muscles: paried with extrinsic; arise in substance of tongue and allow tongue to contort, twist, roll, etc
**CC: all extrinsic muscles innervated by hypoglossal nerve; test by protruding tongue and moving side to side (genioglossus) and then retract (styloglossus) - Hypoglossal nerve, Lingual and Buccal nerves:
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Hypoglossal:
*CNXII
*passes deep to mylohyoid, and superficial to hyoglossus as passes toward tongue
Lingual:
*from V3
*serves gingiva on internal aspect of teeth of mandible
Buccal:
*from V3
*serve lateral gingiva - Clinical Correlations:
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1. vallecula-small depression between glossoepiglottic folds
*CC: putting instrument into vallecula cause epiglottis to fold anteriorly; important when intubating; put blade immediately anterior to epiglottis, which flips out of visual field to expose laryngeal opening
2. paralysis of genioglossus-can lead to obstruction of airway; pull mandible anteriorly
3. lesion of CNXII-genioglossus will not work on side of lesion; other side will push apex of tongue toward side of de-innervation - Lymphatic drainage:
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**tongue is divided into anterior 2/3 and posterior 1/3 by terminal sulcus
1. submandibular: gingiva and all teeth except mandibular incisors, lateral portions of anterior 2/3 of tongue
2. jugulodigastric (found between IJV and common facial vein, drains in deep cervical); bilateral-posterior 1/3 of tongue
3. deep cervical; bilateral-medial part of anterior 2/3 of tongue
4. submental-apex of tongue
*CC: always palpate jugulodigastric, submandibular, and submental nodes while doing oral cavity exam - Tongue arteries and veins:
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**lingual artery (off ECA): will branch into sublingual, deep lingual and dorasal lingual arteries
**lingual vein
**hyoglossus separates artery and vein: vein runs superficial and artery deep
**common facial vein receives facial and lingual veins
**very superficial venous anastomoses on sublingual portion of tongue, which will go to IJV
**CC: dehydrated patients are sometimes hard to put IVs in; easier to put drug under tongue; reach heart directly or indirectly - Dorsum of Tongue:
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1. sulcus terminalis-inverted "V" groove; points to foramen cecum, which is site of embryological genesis of thyroid gland
2. medial sulcus-separates left and right tongue
3. papillae-taste buds sit on
*major papillae are: circum vallate, foliate, filiform, fungiform papillae - Taste:
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**taste buds located on tongue, soft palate, oral pharynx, and epiglottis
**SVA
**CNVII: convey taste fibers via chorda tympani nerve to anterior 2/3 of tongue
**CNIX: both taste and sensation posterior 1/3 of tongue
**CNX: via internal laryngeal branch of superior laryngeal will innervate some bud speckling epiglottis and som on posterior 1/3
Ganglia:
*CNVII: geniculate ganglion
*CNIX: inferior (petrosal) ganglion
*CNX: inferior (nodose) ganglion
General Sensation of tongue:
1. lingual nerve (V3) for anterior 2/3 (GSA)
2. CNIX for posterior 1/3 (GVA)