Laryngology overview Flashcards
What embryologic structures give rise to the larynx?
The endodermal lining and splanchnic mesenchyme of the
foregut formed by branchial arches IV through VI.
Match the branchial arch with its laryngeal
derivative:
A. Corniculate, arytenoid, and cricoid cartilages;
some laryngeal muscles; recurrent laryngeal nerve
B. Upper body of the hyoid bone and its lesser
cornu
C. Epiglottis, thyroid cartilage, cuneiform
cartilages, pharyngeal constrictors, some
laryngeal musculature, superior laryngeal nerve
D. Lower body of the hyoid bone and its greater
cornu
A. V/VI
B. II
C. IV
D. III
The anlagen of the larynx, trachea, bronchia, and
lungs arise from what embryologic structure?
The tracheobronchial groove, a ventromedial diverticulum
of the foregut
What structure obliterates the ventral primitive laryngopharynx during embryologic development?
Epithelial lamina
In the postnatal period, the larynx undergoes
changes in axis, shape, length, and position.
Describe the position of the larynx related to the
cervical vertebra in an infant versus an adult.
● Infant: C1–C4
● Adult (by age 6 years): C4–C7
What are the nine laryngeal cartilages?
Unpaired 1: Cricoid cartilage 2: Thyroid cartilage 3: Epiglottis Paired 4,5: Arytenoid cartilages 6,7: Corniculate cartilages 8,9: Cuneiform cartilages
Name the six intrinsic muscles of the larynx, and
describe both their function and innervation.
● Cricothyroid: Lengthens the vocal cord; external branch of
the superior laryngeal nerve (cranial nerve [CN] X)
● Posterior cricoarytenoid: Abducts the vocal cords; recur-
rent laryngeal nerve (CN X)
● Lateral cricoarytenoid: Adducts the vocal cords; recurrent
laryngeal nerve (CN X)
● Oblique arytenoid: Adducts the vocal cords, recurrent
laryngeal nerve (CN X)
● Transverse arytenoid: Adducts the vocal cords; recurrent
laryngeal nerve (CN X)
● Thyroarytenoid: Relaxes, shortens, and adducts the vocal
cords; recurrent laryngeal nerve (RLN; CN X)
What nerve provides sensation to the larynx?
CN X via the internal branch of the superior laryngeal nerve
above the glottis and the recurrent laryngeal nerve below
the glottis
Glottic sensation is mainly from the superior laryngeal
nerve with some sensory innervation from the RLN as well.
What are the extrinsic muscles of the larynx, and
what is their function and innervation?
● Sternohyoid: Caudal traction on the larynx; ansa cervicalis
nerve
● Sternothyroid: Caudal traction on the larynx; ansa cervi-
calis nerve
● Omohyoid: Caudal traction on the larynx; ansa cervicalis
nerve
● Geniohyoid: Cephalad traction on the larynx; C1 via the
hypoglossal nerve (CN XII)
● Anterior belly of the digastric: Cephalad traction on larynx;
nerve to the mylohyoid (V3)
● Mylohyoid: Cephalad traction on the larynx; nerve to the
mylohyoid (V3)
● Stylohyoid: Cephalad traction on the larynx; facial nerve
(CN VII)
● Thyrohyoid: Caudal traction on larynx; ansa cervicalis
nerve
Describe the subtypes of the laryngeal epithelium.
● Supraglottis: Pseudostratified columnar epithelium (res-
piratory epithelium)
● Glottis: Stratified squamous epithelium
● Subglottis: pseudostratified columnar epithelium (respiratory epithelium)
● Lingual surface of the epiglottis: Stratified squamous
epithelium
● Laryngeal surface of the epiglottis: Stratified squamous
merging into pseudostratified columnar epithelium
What are the layers of the true vocal folds, from superficial to deep?
● Epithelium ● Superficial lamina propria (SLP) ● Intermediate lamina propria ● Deep lamina propria ● Thyroarytenoid muscle complex
What layers form the vocal fold cover, ligament,
and body, respectively, involved in the cover-body
theory of voice production?
● Cover = epithelium + SLP
● Ligament = intermediate lamina propria + deep layers of
the lamina propria
● Body = thyroarytenoid muscle
