larynx

Question 1

functions of larynx

Answer 1

1: regulate passage of materials through the airway (acts like valve)
2: for voice production

Question 2

what are the components of the laryngeal skeleton?

Answer 2

nine cartilages (3 paired, 3 unpaired)
joined by membranes and ligaments
hyoid bone not part of larynx, but has supportive role for some of the ligaments
includes:
epiglottis
thyroid cartilage
arytenoid cartilage
cricoid cartilage
tracheal rings

Question 3

embryological origin of larynx

Answer 3

cartilages and intrinsic muscles derived from mesenchyme of 4th and 6th arches
mucous membrane from endoderm
overall, larynx derived from respiratory diverticulum

Question 4

thyroid cartilage

Answer 4

large, V-shaped cartilage
surrounds anterior part of larynx
suspended from inferior border of hyoid bone via thyrohoid membrane
laminae meet in anterior midline as laryngeal prominence (adam’s apple)

Question 5

laryngeal prominence

Answer 5

where laminae of thyroid cartilage meet in midline

makes adam’s apple

Question 6

cricoid cartilage

Answer 6

only complete ring of cartilage that surrounds the airway
narrow anteriorly and wide posteriorly
articulates with inferior horns of thyroid cartilage

Question 7

epiglottis

Answer 7

leaf-shaped cartilage attached to body of hyoid bone and internal surface of thyroid cartilage
forms anterior border of laryngeal inlet
moves inferiorly during swallowing to cover laryngeal inlet

Question 8

arytenoid cartilage

Answer 8

two small cartilages that resemble pair of boots
resting on upper border of cricoid cartilage
have vocal process that projects anteriorly - vocal ligament attaches here
muscular process projects laterally
highly mobile - can slide, rotate and tilt on superoir surface of cricoid
affects position of vocal ligaments

Question 9

aryepiglottic folds

Answer 9

round bulges contain pairs of supportive cartilages = corniculate and cuneiform
corinculate more medial - rests on top of arytenoid cartilage

Question 10

thyrohyoid membrane

Answer 10

wide membrane that connects upper margin of the thyroid cartilage to the hyoid bone
small hole on each side that transmits superior laryngeal vessels and internal laryngeal nerve

Question 11

quadrangular membrane

Answer 11

extends from epiglottis to arytenoid cartilage
forms aryepiglottic fold and lateral wall of entrance to larynx
lower free boarder = vestibular ligament

Question 12

aryepiglottic fold

Answer 12

formed by quadrangular membrane

Question 13

vestibular ligament

Answer 13

false vocal cord
formed from lower free border of quadrangular membrane
within vestibular fold

Question 14

vestibular fold

Answer 14

vestibular ligament plus mucous membrane covering it

Question 15

conus elasticus/cricothyroid ligament

Answer 15

connects superior surface of cricoid cartilage to the vocal process of arytenoid cartilage and internal midline of the thyroid cartilage
superior free end is thickened, forms true vocal ligament

Question 16

vocal ligament

Answer 16

formed by thickened superior free end of conus elasticus

Question 17

median cricothyroid ligament

Answer 17

mid-portion of conus elasticus

incised during a cricothyrotomy

Question 18

hyoepiglottic ligament

Answer 18

anchors epiglottis to hyoid bone

Question 19

thyroepiglottic ligament

Answer 19

anchors epiglottis to thyroid cartilage

Question 20

interior of larynx

Answer 20

covered by mucous membrane derived from endoderm

most ciliated pseudostratified columnar

Question 21

laryngeal inlet

Answer 21

opening into the larynx from laryngopharynx

boundaries = epiglottis, aryepiglottic folds laterally, interarytenoid notch posteriorly

Question 22

vocal folds

Answer 22

contain true vocal ligament covered by mucous membrane plus vocalis muscles

Question 23

ventricles

Answer 23

lateral recesses between the vestibular folds and vocal folds
each has saccule

Question 24

saccule

Answer 24

anterior projection from ventricle

contains mucous glands that lubricate vocal folds

Question 25

vestibule

Answer 25

area between inlet and vestibular folds

Question 26

glottis

Answer 26

space between vocal cords

Question 27

infraglottic cavity

Answer 27

space inferior to the vocal cords and superior to the trachea

Question 28

sensory innervation to interior of larynx

Answer 28

to area superior to vocal folds: internal branch of superior laryngeal nerve to vocal folds and area inferior to the vocal folds: recurrent laryngeal nerve

Question 29

position of vocal cords during different states?

Answer 29

during quiet respiration: vocal cords partially abducted (glottis open) during forced inspiration: complete adduction of vocal cords (glottis opens fully) phonation: adducted - sound produced when air from lungs forced up through folds effort closure and swallowing: closure of glottis, laryngeal inlet narrows

Question 30

extrinsic muscles of larynx

Answer 30

muscles that move larynx as a whole usually by moving hyoid bone elevate: suprahyoid: geniohyoid; mylohoid; digastrics; stylohyoid depress: infrahyoid: sternohyoid; omohyoid; sternothyroid; thyrohyoid

Question 31

intrinsic muscles of larynx

Answer 31

``` act of specific part of larynx alter length or tension of vocal folds of change size or shape of glottis derived from 4th-6th arches - cricothyroid - thyroarytenoid - vocalis - posterior cricoarytenoid - lateral cricoarytenoid - transverse arytenoid - oblique arytenoid all innervated by recurrent laryngeal nerve except cricothyroid (external branch of superior laryngeal nerve) ```

Question 32

cricothyroid

Answer 32

extends between cricoid and thyroid cartilages pulls anterior part of thyroid cartilage inferiorly, stretching the vocal folds and increasing tension on them innervated by external branch of superior laryngeal nerve (vagus) only intrinsic muscle of larynx not innervated by recurrent laryngeal nerve

Question 33

thyroarytenoid

Answer 33

from internal aspect of thyroid cartilage inserts on lateral border of arytenoid cartilage sphincter of vestibule innervated by recurrent laryngeal nerve

Question 34

vocalis

Answer 34

between arytenoid cartilage and internal aspect of thyroid cartilage medial portion attaches to vocal ligament adjusts tension of vocal fold innervated by recurrent laryngeal nerve

Question 35

posterior cricoarytenoid

Answer 35

from posterior surface of cricoid cartilage passes upward and laterally inserts on muscular process of arytenoid cartilage innervated by recurrent laryngeal nerve action opposes that of lateral cricoarytenoid pulls muscular process of arytenoid toward midline causes vocal process of arytenoid to move laterally => vocal ligaments move apart => abduction of vocal fold innervated by recurrent laryngeal nerve

Question 36

lateral cricoarytenoid

Answer 36

from superior surfface of cricoid cartilage passes up and backward inserts on muscular process of arytenoid cartilage innervated by recurrent laryngeal nerve action opposes that of posterior cricoarytenoid pulls muscular process of arytenoid cartilage laterally => vocal processes move medially => adduction of vocal fold

Question 37

transverse arytenoid

Answer 37

extends between the two arytenoid cartilages fibers oriented in transverse fashion moves arytenoid cartilages closer together => closing posterior portion of glottis innervated by recurrent laryngeal nerve

Question 38

oblique arytenoid

Answer 38

muscle fibers extend from one arytenoid to the other, but fibers oriented in oblique fashion some continue upward in aryepiglottic fold = aryepiglottic muscle act as sphincters => reduce size of laryngeal inlet innervated by recurrent laryngeal nerve

Question 39

aryepiglottic muscle

Answer 39

upward extension of fibers from oblique arytenoid acts as sphincter => reduces size of inlet innervated by recurrent laryngeal nerve

Question 40

course of recurrent laryngeal nerve in thorax

Answer 40

enters thorax and loops around aortic arch | if patient presents with hoarse voice, must consider pathology of thorax

Question 41

blood supply to larynx

Answer 41

from superior and inferior laryngeal arteries | branches of superior and inferior thyroid arteries

Question 42

superior laryngeal artery

Answer 42

branch of superior thyroid artery from ECA travels through hole in thyrohyoid membrane with internal laryngeal nerve blood supply to larynx

Question 43

inferior laryngeal artery

Answer 43

branch of inferior thyroid artery = branch of thyrocervical trunk ascends along trachea with recurrent laryngeal nerve enters larynx at inferior border of inferior pharyngeal constrictor muscle