larynx Flashcards
what is the larynx?
organ of voice production and the parts of the respiratory tract between the lower pharynx and trachea
what is the function of the larynx?
acts as a compound sphincter to prevent passage of food/drink into airway
forms a framework of cartilage for the attachment of ligaments and muscles
what is the larynx comprised of?
3 unpaired cartilages (epiglottis, thyroid, cricoid)
3 paired cartilages (arytenoid, cuneiform, corniculate)
a fibro-elastic membrane
intrinsic muscles
location of larynx
anterior to C3-6
innervation of larynx
vagus n. CN X
describe the epiglottis
flexible due to high elastin content
attached to thyroid cartilage by thyro-epiglottic ligament
attached to hyoid by hypo-epiglottic ligament
describe the thyroid cartilage
largest of the cartilages
two plate-likelaminaefuse anteriorly in the median plane forming laryngeal prominence
Superior to laryngeal prominence, the laminae diverge to form a V-shapedsuperior thyroid notch (there is an inferior notch, but it’s less visible)
The posterior border of each lamina projects superiorly as thesuperior hornand inferiorly as theinferior horn
superior border of thyroid cartilage lies _____
opposite C4
describe cricoid cartilage
articulates with the thyroid cartilage
shaped like a signet ring
posterior= lamina
anterior= arch
3 sided pyramidal cartilages that sit atop of the cricoid cartilage
arytenoid cartilage
function of vocal processes on arytenoid cartilage
vocal ligaments attach to these cartilages anteriorly
function of muscular processes of arytenoid cartilage
projects laterally to serve as a lever for laryngeal muscles
action of arytenoid cartilages
slide, tilt and rotate to approximate, tense and relax vocal cords
describe cricothyroid membrane
anteriorly attached to thyroid cartilage
posteriorly attached to vocal process of arytenoid cartilages
what is the vocal ligament?
upper margin of cricothyroid membrane that is free and thickened
true vocal cords
describe quadrangular membrane
runs between epiglottis and arytenoid cartilages
cuneiform cartilages are contained within this membrane
what is the vestibular ligament?
free lower margin of quadrangular membrane
false vocal folds
what makes up the vocal fold?
vocal ligament + vocalis m.
what is the purpose of the vestibular folds?
serve to protect the vocal folds
action of cricothyroid muscles
pulls thyroid cartilage anteriorly on the cricoid cartilage
stretches and tenses vocal cords (high pitch)
innervation of cricothyroid muscles
external branch of superior laryngeal nerve (CN X)
action of posterior cricoarytenoid muscle
externally rotate the vocal process of the arytenoid cartilages
open the rima glottidis
only abductor of the vocal folds
innervation of transverse, oblique, posterior and lateral cricoarytenoid muscle, thyroarytenoid and vocalis muscles
recurrent laryngeal nerve
action of lateral cricoarytenoid muscle
internally rotate the vocal process of the arytenoid
close the rima glottidis
adduct vocal folds
action of transverse and oblique arytenoid muscles
adduct and narrow laryngeal inlet
action of thyroarytenoid and vocalis muscles
narrow laryngeal inlet
relax vocal folds
describe thyrohyoid membrane
between thyroid cartilage and hyoid
laterally contains two apertures which allow internal branch of superior laryngeal n. and superior laryngeal a. passage into the internal surface of larynx
describe cricotracheal ligament
attaches the cricoid cartilage to the first tracheal ring
describe hypo-epiglottic ligament
attaches epiglottic cartilage to hyoid
describe the laryngeal vestibule
extends from laryngeal inlet to vestibular fold
comprised of laryngeal inlet and quadrangular membrane
describe the central (middle) cavity
space between vestibular and vocal folds
laryngeal ventricles and saccules = lateral bulge of the mucosa
describe the infraglottic cavity
space from vocal folds to inferior border of cricoid cartilage
comprised of cricothyroid membrane and cricoid cartilage
what is the rima glottidis?
space between vocal folds
what is the rima vestibuli?
space between the vestibular folds
motor innervation to cricothyroid
external laryngeal nerve
sensory and parasympathetic innervation of larynx superior to vocal folds
internal laryngeal nerve
sensory innervation of the larynx inferior to the vocal folds and motor innervation of all intrinsic muscles of the larynx except cricothyroid muscle
recurrent laryngeal nerve
what is an important relationship between recurrent laryngeal n. and thyroid gland
the recurrent laryngeal n. ascends superiorly to the posteromedial aspect of the thyroid gland
what is an important relationship between the piriform recess and internal laryngeal nerve?
the internal laryngeal n. lies deep to the mucosa of the piriform recess making it vulnerable to injury when a foreign body lodges in the fossa
describe the superior laryngeal artery
branch of superior thyroid artery off the external carotid artery
supplies upper half of larynx
accompanies internal branch of superior laryngeal n. through thyrohyoid membrane
describe the inferior laryngeal artery
branch of inferior thyroid artery of thyrocervical trunk of the subclavian artery
supplies lower half of larynx
ascends in tracheo-esophageal groove with recurrent laryngeal nerve
describe lymphatic drainage above the vocal folds
follow superior laryngeal vessels through thyrohyoid membrane and drain into superior deep cervical nodes
describe lymphatic drainage below the vocal folds
drain into pre-tracheal or para-tracheal nodes which drain into inferior deep cervical nodes
important structures at C3/4
superior border of thyroid cartilage
common carotid artery bifurcation
location of hyoid
