The abductor of vocal cord is
Ans. a (Posterior cricoarytenoid) (Ref BDC vol. 3/4th/243)Posterior Cricoarytenoid is known to be the only abductor of the larynx. It opens space between the vocal cords (abduct) by rotating the arytenoids laterally (abduct), causing the vocal cords to separate opening the rima glottidis. Posterior cricoarytenoid muscle is called the safety muscle because ail the intrinsic muscles are adductors of the vocal cords except posterior cricoarytenoids which are abductors. The cricothyroid muscle is the only tensor of the larynx aiding with phonation and should not to be confused with the posterior cricoarytenoid muscles, which are the only muscles directly responsible for opening (abducting) the space between the vocal cords.Laryngeal muscleAction1.Aryepiglottic MuscleDraws the epiglottis posteriorly and downward during swallowing2.Oblique ArytenoidDraws arytenoid cartilages together, adducting vocal folds3.Transverse ArytenoidDraws arytenoid cartilages together, adducting vocal folds4.ThyroarytenoideusDraws arytenoid cartilage forward, relaxing and adducting the vocal folds5.Vocalis muscle^Relaxes segments of the vocal ligament, thereby adjusting voice pitch.Educational Points# Larynx begins at C4 & ends at C7 vertebral levels Q# The only intrinsic muscle of larynx that lies outside the laryngeal framework is Cricothyroid.LIGAMENTS OF LARYNX# The extrinsic ligaments of the larynx are those connecting the thyroid cartilage and epiglottis with the hyoid bone and the cricoid cartilage with the trachea.# The intrinsic ligaments of the larynx are those connecting several cartilages ofthe organ to each other. They are considered the elastic membrane of the larynx.A Structural ligaments - hold larynx, hyoid and trachea together1. Thyrohyoid membrane-link thyroid cartilage to hyoid bone;medial part is median thyrohyoid ligament.2. Cricothyroid membrane - links cricoid to thyroid cartilage; thickened medial and anterior part called Median cricothyroid ligament.3. Cricotracheal ligament - links cricoid to first tracheal cartilage.4. Quadrangular membrane - links arytenoid to epiglottis; lower free edge is called vestibular ligament.5. Thyroepiglottic ligament - links epiglottis to thyroid cartilage.B. Functional LigamentsConus elasticus - elastic membrane forming vibrating lips; arises from entire upper edge of arch of cricoid; attaches anteriorly to thyroid cartilage, posteriorly to vocal processes of arytenoid cartilages; upper free edges are thickened to form vocal ligaments; opening between vocal ligaments is called rima glottidis. Functions of conus elasticus: Sound production and Closing rima glottidis.
Posterior cricoarytenoid
Lateral cricoarytenoid
Thyroarytenoid
Cricoarytenoid
Larynx