Larynx Flashcards
Thyroid Cartilage
Unpaired cartilage. Largest of the laryngeal cartilages. Two quadrilateral laminae, opened posteriorly, and fuse anteriorly to form the laryngeal prominence. The thyroid cartilage diverges superiorly above the laryngeal prominence to form a v-shaped thyroid notch. Posterior border projects Superior and Inferior Horns
Laryngeal prominence
“Adam’s apple”, formed by the angle of the thyroid cartilage
Thyroid Notch
v shaped notch of the thyroid cartilage superior to the laryngeal prominence
Superior and inferior horns of thyroid cartilage
Posterior borders of thyroid cartilage; open in back
Cricoid cartilage
Unparied. Signet ring-shaped cartilage (only cartilage that forms an entire ring). Signet is in the back (lamina), anterior band is the arch. Thicker and stronger than the thyroid cartilage. Forms interior of the larynx
Arch
Anterior band of cricothyroid
Lamina
Signet-ed band in back of cricothyroid cartilage
Epiglottic Cartilage
Forms superior part of anterior wall and superior margin of the inlet of the larynx. Inferior end is attached to the thyroid cartilage via thyroepiglottic ligament
Thyroepiglottic ligament
Connects thyroid cartilage to epiglottic cartilage
Arytenoid Cartilage
Paired cartilages. Pyramidal-shaped with both vocal (anteromedial) and muscular processes (posterolateral). Apex is superior, base is inferior. Important for vocal cords
Corniculate Cartilage
Paired cartilages. Small cartilage nodules in the aryepiglottic fold; lie on the apex of the arytenoid cartilage. Support the aryepiglottic fold
Cuneiform Cartilage
Paired cartilages. Small cartilage nodules in aryepiglottic fold. Support the aryepiglottic fold
Cricothyroid Joint
Synovial joint. Fibrous capsule, enages in rotation and gliding motion. Joint between the inferior horn of the thyroid cartilage and the lateral surface of the cricoid cartilage. Tilt anterior/posteriorly: back and forth, some rotation
Cricoarytenoid Joint
Synovial joint, plane type. Can rotate, anterior, posterior side to side. Allow for vocal cords to move (not turn all around).
Thyrohyoid Membrane
Extrinsic ligament of the larynx connecting the thyroid cartilage with the hyoid bone. Suspends the larynx from the hyoid bone. Internal laryngeal nerve and superior laryngeal artery pierce this membrane to enter the larynx
Cricotracheal Ligament
Ligament of the larynx connecting the cricoid cartilage to the first tracheal ring.
Cricothyroid Ligament
Ligament of the larynx connecting the cricoid cartilage to the thyroid cartilage. Has a median portion and twin lateral portions surrounding it.
Median cricothyroid ligament
Point where the skin is closest to the airway. Most accessible for an emergency cricothryoidotomy.
Vocal ligament (fold)
True vocal cord. The elastic ligament extends from the junction of the laminae of the thyroid cartilage (anteriorly) to the vocal processes of the arytenoid cartilages (posteriorly).
Conus Elasticus
Elastic membrane extending from cricoid cartilage to the vocal ligament. Consists of median cricothyroid ligament, vocal ligament, and cricothyroid ligament
Quadrangular Membrane
Thin submucosal sheet of connective tissues. Extends from arytenoid cartilage to the epiglottic cartilage. Covered by the aryepiglottic fold
Vestibular Ligament
False vocal cords. These are free edges of the quadrangular membrane. Do not produce sound
Age changes of Vocal Cords
Growth until age 3. At puberty, male laryngeal cavity enlarge and laryngeal walls thicken. Vocal folds lengthen and thicken (both men and women, but men more abruptly). Laryngeal prominence becomes visible and protrudes.
Interior of Larnyx
3 Compartments: vestibule, ventricles, and infraglottic cavity.
Vestibule of the larynx
Cavity superior to the vestibular folds
Ventricle of the larynx
Cavity of the lateral walls between the vestibular and vocal folds. One per side. Responsible for the “deep-ness” of an individual’s voice.
Infraglottic Cavity
Space below vocal folds, between the vocal folds and the inferior border of the cricoid cartilage
Rima Glottis
Aperture between the vocal folds
Glottis
Vocal folds, rima glottiis and narrow part of the larynx at the level of the vocal folds. Part of the larynx most directly associated with voice production
Rima vestibuli
Aperture between the vestibular folds. Protective mechanism; keeps larynx closed during swallowing
Extrinsic muscles of the larynx
Infrahyoid and suprahyoid
Infrahyoid muscle
Depressor of the hyoid bone and larynx; result in LOW pitch voice
Suprahyoid bone
Elevator of hyoid bone and larynx; result in HIGH pitch voice
Intrinsic muscles of larynx
Muscles that close laryngeal inlet (Transverse arytenoid, oblique arytenoid), Muscles that ADDuct the larynx (lateral cricoarytenoid), muscles that abduct the vocal cords (posterior cricoarytenoid), muscles that tense the vocal cords (cricothyroid), muscles that relax the vocal cord (thyroarytenoid), and Vocalis muscle
Transverse arytenoid
Adduct the arytenoidal cartilage, CLOSING the laryngeal inlet. Closes vocal folds and rima glottis. Reccurent laryngeal of CNX
Action of the Transverse Arytenoid
Adducts arytenoid cartilage (closes rima glottidis)
Oblique Arytenoid
Adduct the arytenoidal cartilage, CLOSING the laryngeal inlet. Closes the rima glottis. Recurrent laryngeal of CNX
Action of the Oblique Arytenoids
Adducts arytenoid cartilages (closes rima) [No image from slides =(]
Lateral Cricoarytenoid
Extends between cricothyroid and muscular processes of aretynoid. Adducts vocal cords and medially rotates arytenoid cartilage (closes rima glottidis). Recurrent laryngeal of CNX.
Action of the Lateral Cricoarytenoid
Adducts vocal cords and medially rotates arytenoid cartilage (closes rima glottidis)
Posterior cricoarytenoid
Extend from cricoid cartilage to muscular process of arytenoid cartilages. Abducts vocal cords, and laterally rotates the arytenoid cartilage, allows air to leave by rima glottis opening. Recurrent nerve of CN X.
Action of Posterior Cricoarytenoid
Abducts vocal cords, opens rima glottis
Cricothyroid Muscle
Tenses the vocal cords. Outside of the larynx, “tighten guitar string” makes pitch HIGH
Action of Cricothyroid
produces tension and elongation of the vocal folds; results in high pitch
Thyroarytenoid
Relaxes the vocal cords. parallel to vocal cord, relaxer of vocal cords , thyroid to arytenoid. “Loosen guitar string”, pitch lower
Action of Thyroarytenoid
Relaxes vocal folds. “Loosen guitar string”, pitch lower
Vocalis muscle
formed by several of the finer and most medial fibers of the thyroaryteroid muscle attached directly to the outer side of the vocal ligament. Originates between two laminae of thyroid cartilage, inserts at portions of the vocal ligament/vocal process of arytenoid. Shortens and relaxes portions of vocal cords. Recurrent Laryngeal of CN X
Blood supply
Superior and Inferior laryngeal arteries (branches of superior and inferior thyroid arteries [branches of external carotid and thyrocervical trunk of subclavian, respectively]). Superior and inferior thyroid arteries eventually anastamose with their paired sides and with each other (superior with inferior).
Superior thyroid artery
First branch of the external carotid artery. Enters through the thyrohyoid membrane just below the hyoid bone. Gives off superior laryngeal artery for blood supply to larynx
Inferior thyroid artery.
Branch of thyrocervical trunk off of the subclavian artery. Gives off inferior laryngeal artery for supply to larynx.
CN X
Gives off two relevant branches for innervation to the larynx: Superior laryngeal and recurrent laryngeal.
Superior laryngeal
Internal laryngeal branch (sensory) and external laryngeal branch (motor)
Internal laryngeal branch
Provides sensory innervation to regions of the larynx above the vocal folds
External Laryngeal branch
Provides motor innervation. Functions to tense the vocal cords by activating the cricothyroid muscle, increasing pitch. Gives branches to pharyngeal plexus.
Recurrent Laryngeal
All intrinsic muscles except cricothyroid (which is external laryngeal). Sensory for laryngeal area below the vocal folds. Right recurrent laryngeal nerve loops under right subclavian artery and the left recurrent loops under the aortic arch, then both ascend up to the larynx. Locate these nerves, in the neck, in groove between the trachea and esophagus as it moves superiorly, deep to the thyroid gland, to the larynx
