Head & Neck VII: Larynx

cricoid: articulations

lateral surface: inferior horn of thyroid cartilage; upper surface: base of arytenoid cartilage

arytenoid: attachments

vocal process that gives attachment to vocal ligament and cricoarytenoid muscles

thyrohyoid membrane: actions + innervation

suspends larynx from hyoid bone; pierced by superior laryngeal artery and vein, and internal laryngeal nerve

quadrangular membrane: function

forms paired vestibular ligaments which form the vestibular (false) vocal folds. also forms aryepiglottic folds

conus elasticus: function

connects the cricoid and thyroid cartilages. forms vocal ligament.

what structure is responsible for producing sound?

vocal folds

what adjusts the tension and degree of approximation of the vocal folds?

laryngeal muscles

function of vestibular folds

protection

what are the elevators of extrinsic laryngeal muscles?

suprahyoid muscles, stylopharyngeus, salpingopharyngeus, palatopharyngeus

what are the depressors of extrinsic laryngeal muscles?

infrahyoid (strap) muscles

oblique arytenoid: actions

ADduction; facilitates food going into piriform recesses and into esophagus

transverse arytenoid: actions

ADduction; close vocal folds during complete closure of airway

lateral (intrinsic) cricoarytenoid: actions

ADduct vocal folds

posterior (intrinsic) cricoarytenoid: actions

ABduct vocal fold and arytenoid cartilage

cricothyroid (intrinsic) muscles: actions

stretch vocal ligament to raise pitch of voice

thyroarytenoid: actions

stiffen vocal ligament to produce loud sounds

what muscle makes minute adjustments in tension during speech?

vocalis muscle

motor innervation of intrinsic laryngeal muscles; cricothyroid is innervated by what nerve?

recurrent inferior laryngeal nerve; cricothyroid is innervated by external laryngeal nerve

sensory innervation of mucosa from the vocal folds upwards and below the vocal folds

upwards vocal folds is innervated by internal laryngeal nerve; below vocal folds is innervated by recurrent laryngeal nerve

blood supply of larynx

superior laryngeal artery and inferior laryngeal artery (from respective thyroid arteries)

what function: larynx is elevated by the suprahyoid muscles and other elevators. The inlet is narrowed by the oblique arytenoid and aryepiglottic muscles.

swallowing

what function: rima glottidis is closed by the sphincters. expiratory muscles are contracted.

coughing/sneezing

what action: rima glottidis is closed after deep breath. Air trapped in lungs → diaphragm can’t move upwards when abdominal muscles are contracted → pressure transmitted to pelvis and abdomen

micturition (urination), defecation, parturition (childbirth)

what action: vocal ligaments ADducted. entire larynx is either elevated or depressed

voice production: high-pitch, low-pitch