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Region 7: Oral Cavity and Larynx
Oral Cavity
--vestibule: smaller external portion
*roof: hard and soft palates
*tongue occupies most of the oral cavity
*Floor of sublingual region contains:
a. lingual frenulum (anchors tongue to the floor)
b. sublingual folds (either side of frenulum)
c. sublingual carnuncles (each side of frenulum containing opening of
the submandibular/Wharton’s ducts
Palate
--hard palate (bony palate)
*formed by palatine processes of maxillae (anterior) and horizontal plates of
the palatine bones (posterior)
*contains greater palatine vessels, greater palatine and nasopalatine nerves
--soft palate
*fibromuscular tissue suspended from the posterior edge of the hard palate
*continuous laterally w/ palatoglossal and palatopharyngeal arches
*sensory inn by lesser palatine n.
*uvula projects downward n median plane
*Muscles of the soft palate
a. Levator veli Palatini
--O: cartilage of auditory tube
--I: upper surface of palatine aponeurosis
--Inn: cranial portion of accessory n. through vagus and
pharyngeal plexus
b. tensor veli palatini
--O: scaphoid fossa at base of medial pterygoid plate
--its tendon goes around pterygoid hamulus
--I: tendons of opp. sides expand and attach to posterior border
of hard palate (forming palatine aponeurosis)
--Inn: mandibular n.
c. palatopharyngeus
--O: posterior border of palatine aponeurosis
--occupies palatopharyngeal arch
--Inn: cranial portion of accessory n. through vagus and
pharyngeal plexus
d. palatoglossus muscle
--O: inferior surface of palatine aponeurosis
--I: mucous mem. of tongue
--Inn: cranial portion of accessory n. through vagus and
pharyngeal plexus
e. musculus uvulae
--O: palatine aponeurosis
----Inn: cranial portion of accessory n. through vagus and
pharyngeal plexus
*Sensory Innervation: lesser palatine nerve
Tongue
--apex/tip: rests against incisor teeth
--dorsum: related to palate
*Sulcus terminalis (v shaped groove divided into anterior (2/3 oral part) and
posterior (1/3 pharyngeal part)
*Circumvallate papillae: arranged in a row in front of the sulcus terminalis
(contains taste buds)
*faramen cecum: located in mid-point of sulcus
--inferior surface of tongue attached to floor of mouth by lingual frenulum
--Extrinsic Muscles of the Tongue
a. Genioglossus
*O: immediately above geniohyoid
*Act: protracts the tongue
b. Hyoglossus
*hypoglossal and lingual nerves pass superficial/lateral to it
*Act: depresses the tongue
c. Styloglossus
*I: into lateral and inferior aspect of tongue
*Act: retracts the tongue
--Intrinsic muscles of the tongue
a. longitudinal
b. vertical
c. transverse
--Innervation
*Motor: all muscles (except palatoglossus) hypoglossal nerve
*General Sensation:
a. anterior 2/3: lingual nerve (from CN V)
b. posterior 1/3: glossopharyngeal n. (CN IX)
*Taste:
a. anterior 2/3: facial n. through chorda tympani n.
b. posterior 13: glossopharyngeal n. (CN IX)
--Blood Supply
*lingual artery
Larynx
--Cartilages of the Larynx
a. Thyroid cartilage (shield like shape)
*composed of right and left laminae
*laryngeal prominence (adam’s apple)
*superior thyroid notch
*superior cornu/horn: attached to greater horn of hyoid bone
*inferior cornu/horn: articulates with the cricoid cartilage
*oblique line: crosses the lateral surface of the laminae, gives
attachments to sternothyroid, thyrohyoid and inf. constrictor mm.
b. Cricoid cartilage (signet ring shape)
*at level of C6
*attached above to the thyroid cartilage by the cricothyroid ligament
c. Epiglottis cartilage (leaf shape)
*in front of laryngeal inlet
*b/w epiglottis and base of tongue are spaces called valleculae
d. Arytenoid cartilages (pyramidal shape and 2 of them)
*base is articulated with the upper border of the lamina of the cricoid
cartilage
*apex supports the corniculate cartilage
*base projects anteriorly as vocal process that gies attachment to the
vocal ligament
*lateral projection of the base has the muscular process
e. Corniculate cartlages
*situated on the apices of the arytenoid cartilages
f. Cuneiform Cartilages
*located in aryepiglottic fold
--Membranes and Ligaments of the Larynx
a. thyrohyoid membrane
*connects thyroid cartilage to hyoid bone
*membrane pierced by internal laryngeal n. and superior laryngeal a.
b. cricothyroid ligament
*connects arch of cricoid to thyroid cartilage
*in acute respiratory obstruction, cricothyroid lig. is separated by
piercing it with a sharp instrument to make a temporary airway
c. conus elasticus
*arises from the upper border of the arch of the cricoid cartilage and
runs medially and upward
*anteriorly, its upper margins are attached to inner surface of the
thyroid cartilage, deep to cricothyroid ligament
*posteriorly, its upper margins are attached to vocal processes of the
arytenoid cartilages
d. vocal ligaments
*upper thickened edges of the conus elasticus
*anterior attachment to thyroid cartilage is fixed but its posterior
attachment to vocal process of the arytenoid is moveable
*epithelial coverings over the vocal ligament form the vocal folds/true
vocal cords
--Joints of the Larynx
a. cricothyroid joint: synovial joints on both sides b/w cricoid and inferior
horns of the thyroid cartilages
--Interior of the Larynx
a. inlet/aditus/entrance of the larynx
*piriform recesses of pharynx are lateral to laryngeal inlet
b. vestibule: extends from inlet to vestibular folds
*vestibular/ventricular folds (aka false vocal cords): extend from
thyroid cartilage anteriorly to arytenoid cartilages posterior (above
vocal process)
*rima vestibuli: space /w the vestibular folds
c. ventricle: on each side extends from vestibular folds to vocal folds
*saccule: upward extension of the ventricle
*laryngocele: enlarged saccule
d. glottis: consists of vocal fold and space b/w (rima glottidis)
*vocal fold/true voal cords: below the ventricles, contain vocal
ligament, vocal processes of the arytenoid cartilages, and vocalis m.
*rima glottidis: narrowest part of the larnygeal cavity, its shape and
size are altered by movement of the arytenoid cartilages
e. subglottic/infraglottic cavity
*extends from rima glottidis
--Sensory Inn. of Larynx
a. internal laryngeal branch of superior laryngeal n: supplies mucous mem. as
far down as vocal folds
b. recurrent laryngeal n: supples mucous mem. below the vocal fold
--Extrinsic Muscles of the Larynx
--Intrinsic muscles of the Larynx
a. cricothyroid m.
*O: external surface of the arch of cricoid cartilage
*Act: act on cricothyroid joints to tilt the lamina of the cricoid
cartilage backward and slide the thyroid cartilage slightly forward
thus lengthening, tensing, and adducting the vocal fold
*Inn: external laryngeal branch of the superior laryngeal n.
b. lateral cricoarytenoid m.
*Inn: recurrent n.
*Act: adductor of vocal fold
c. thyroarytenoid m.
*Inn: recurrent n.
*Act: adductor of vocal fold
d. vocalis m.
*Inn: recurrent n.
*Act: adductor of vocal fold
e. arytenoideus m.
*Inn: recurrent n.
*Act: adductor of vocal fold
f. posterior cricoarytenoid m.
*Inn: recurrent n.
*only abductor of the vocal folds
--Blood Supply of the Larynx
a. superior laryngeal branch of superior thyroid a (branch from external
carotid a.)
b. inferior laryngeal branch of the inferior thyroid a (branch from
thyrocervical trunk off of subclavian a)