Laryngeal Intrinsic Muscles

Question 1

cricothyroid

parts
course
function
innervation

Answer 1

parts- straight and oblique
course- from ventral side of the cricoid cartilage laterocranially to the caudal margin of the thyroid cartilage
function- moves the thyroid cartilage ventrocaudally while concurrently moving the arch of the cricoid cartilage cranially, tightening the vocal cords
innervation- external branch of superior laryngeal nerve

Question 2

lateral cricoarytenoid

course
function
innervation

Answer 2

course- from the cranial part of the lateral margin of the cricoid cartilage to the muscular process of the arytenoid cartilage
function- moves the muscular process ventrolaterally, adducting the vocal cords and closing the intermembranous part of the rima glottidis
innervation- recurrent laryngeal nerve

Question 3

thyroarytenoid - vocalis and thyro-epiglottic part
course
function
innervation

Answer 3

course- from internal side of the thyroid cartilage along the external side of the vocal ligament to the vocal process of the arytenoid cartilage
function- internal rotation and ventral shift of the arytenoid cartilage - addiction and shortening of the vocal ligament (narrows the rima glottidis)

vocalis- medial part of the thyroarytenoid, shortens and relaxes the vocal ligament
thyro-epiglottic part - course- fascicles of the thyroarytenoid from the thyroid cartilage extending to the lateral margin of the epiglottis
function- moves the margins of the epiglottis ventrally enlarging the rima glottidis
innervation- recurrent laryngeal nerve

Question 4

posterior cricoarytenoid

course
function
innervation

Answer 4

course- begins on the dorsal side of the cricoid cartilage and runs craniolaterally to the muscular process of the arytenoid cartilage
function- external rotation and abduction of the arytenoid cartilage - abducts and lengthens the vocal ligament, enlarging the laryngeal inlet
innervation- recurrent laryngeal nerve

Question 5

transverse arytenoid

course
function
innervation

Answer 5

course- transversally connects both arytenoid cartilages on their dorsal side
function- adduction of the arytenoid cartilages - adducts the vocal ligaments, narrowing the rima glottidis
innervation- recurrent laryngeal nerve

Question 6

oblique arytenoid

course
function
innervation

ary-epiglottic part
course
function

Answer 6

course- obliquely connects both arytenoid cartilages on their dorsal sides
function- adduction of the arytenoid cartilages - adducts the vocal ligaments, narrowing the rima glottidis
innervation- recurrent laryngeal nerve

ary-epiglottic part
course- fascicles of the oblique arytenoid extending to the lateral margin of the epiglottic cartilage
function- moves the margins of the epiglottis dorsocaudally, and thus depresses the epiglottis, closing the laryngeal inlet