Larynx

Question 1

Note: there is a small formatting error in this deck. on ppt a “right arrow” did not paste into the answers and instead is a box. The box therefore means “leads to” or “next step.”

What are the two basic functions of the larynx?

Answer 1

to regulate the passage of materials through the airway (it acts like a valve)
voice production.

Question 2

What does the larynx open into superiorly and inferiorly?

Answer 2

Superiorly  laryngopharynx

inferiorly  trachea.

Question 3

How many cartilages make up the skeleton of the larynx?

Answer 3

nine cartilages (3 paired, 3 unpaired) joined by membranes and ligaments.

Question 4

Is the hyoid bond part of the larynx?

Answer 4

The hyoid bone is not part of the larynx, but it serves a supportive function for some of the ligaments.

Question 5

What embryological pharyngeal arches become the Larynx? What embryological tissue?

Answer 5

mesenchyme of the 4th and 6th pharyngeal arches.

Question 6

The thyroid cartilage is the large V-shaped cartilage that surrounds the anterior part of the larynx. It is suspended from the inferior border of the hyoid bone via the thyrohyoid membrane. Its two laminae meet in the anterior midline as the laryngeal prominence (Adam’s apple). It has superior horns and inferior horns.

Answer 6

The thyroid cartilage is the large V-shaped cartilage that surrounds the anterior part of the larynx. It is suspended from the inferior border of the hyoid bone via the thyrohyoid membrane. Its two laminae meet in the anterior midline as the laryngeal prominence (Adam’s apple). It has superior horns and inferior horns.

Question 7

The cricoid cartilage is the only complete ring of cartilage that surrounds the airway. It is narrow anteriorly and wide posteriorly. The cricoid cartilage articulates with the inferior horns of the thyroid cartilage.

Answer 7

The cricoid cartilage is the only complete ring of cartilage that surrounds the airway. It is narrow anteriorly and wide posteriorly. The cricoid cartilage articulates with the inferior horns of the thyroid cartilage.

Question 8

What forms the anterior border of the laryngeal inlet?

Answer 8

The epiglottis

Question 9

What are the attachments of the epiglottis?

Answer 9

body of the hyoid bone

internal surface of the thyroid cartilage

Question 10

What is the movement of the epiglottis during swallowing?

Answer 10

inferiorly to cover the laryngeal inlet.

Question 11

What are the arytenoid cartilages?

Answer 11

two small cartilages that resemble a pair of boots resting on the upper border of the cricoid cartilage.

Question 12

What are the two processes coming off the arytenoid cartilages? Which projects anteriorly? Which projects laterally?

Answer 12

a vocal process that projects anteriorly (for attachment of the vocal ligament)
a muscular process that projects laterally (for attachment of muscles).

Question 13

What are two additional pairs of cartilages are found within the aryepiglottic folds?

Answer 13

the corniculate

cuneiform cartilages

Question 14

What do the corniculate and cuniform cartilages do? What is their relative postion?

Answer 14

supportive role

corinculate is the more medial cartilage that rests on top of the arytenoid cartilage

Question 15

What is the thyrohyoid membrane?

Answer 15

a wide membrane that connects the upper margin of the thyroid cartilage to the hyoid bone.

Question 16

What artery and nerve pass through the thyrohyoid membrane?

Answer 16

the superior laryngeal vessels and the internal laryngeal nerve.

Question 17

What is the quadrangular membrane? What is the aryepiglottic fold?

Answer 17

extends from the epiglottis to the arytenoid cartilage

The quadrangular membrane forms the aryepiglottic fold and the lateral wall of the entrance to the larynx

Question 18

What is the vestibular ligament? What is the vestibular fold?

Answer 18

The lower free border of quadrangular membrane is the vestibular ligament (false vocal cord), which is found within the vestibular fold (fold = ligament + mucous membrane covering it).  
vestibular folds (i.e. false vocal cords) consist of the vestibular ligaments surrounded by mucous membrane.

Question 19

What is the conus elasticus? What is the vocal ligament?

Answer 19

Taka cricothyroid ligament
connects the superior surface of the cricoid cartilage to the vocal process of the arytenoid cartilage and the internal midline of the thyroid cartilage.
The superior, free edge of the conus elasticus is thickened and forms the true vocal ligament.

Question 20

What is the median cricothyroid ligament? What is its clinical relevance?

Answer 20

The mid-portion of the conus elasticus is called the median cricothyroid ligament. This ligament is incised during a cricothyrotomy.

Question 21

What are the hyoepiglottic and thyroepiglottic ligaments?

Answer 21

anchor the epiglottis to the hyoid bone and thyroid cartilage, respectively.

Question 22

The membrane from the interior of the larynx comes from what germ layer?

Answer 22

endoderm (the larynx is derived from the respiratory diverticulum).
ciliated pseudostratified columnar?

Question 23

What is the laryngeal inlet (laryngeal aditus)? What are its boundaries?

Answer 23

the opening into the larynx from the laryngopharynx.
Its boundaries are the 
epiglottis anteriorly
the aryepiglottic folds laterally
the interarytenoid notch posteriorly.

Question 24

What is the vestibule?

Answer 24

the area between the laryngeal inlet and the vestibular folds.

Question 25

What are the Vestibular Folds?

Answer 25

consist of the vestibular ligaments surrounded by mucous membrane.

Question 26

What are the Vocal Folds? What is the vocalis?

Answer 26

The vocal folds (i.e. true vocal cords) are likewise comprised of mucous membrane over the vocal ligaments
however there are also some muscle fibers within the folds called the vocalis muscles (not shown in this image).

Question 27

What are the ventricles and the saccule of the vocal apparatus?

Answer 27

The lateral recesses between the vestibular folds and vocal folds are called the ventricles.
Each ventricle has an anterior projection called a saccule, which contains mucous glands that lubricate the vocal folds.

Question 28

What is the glottis (a.k.a. rima glottidis)?

Answer 28

is the space between the vocal cords.

Question 29

What is the Infraglottic Cavity?

Answer 29

the space inferior to the vocal cords and superior to the trachea.

Question 30

Sensory innervation to the interior of the larynx is provided by what nerves? Superior and inferior to vocal cords…

Answer 30

the internal branch of the superior laryngeal nerve (area superior to the vocal folds) and the recurrent laryngeal nerve (the vocal folds and the area inferior to the vocal folds).

Question 31

What are the muscles that elevate the hyoid and larynx? (Elevation of the larynx is important during swallowing)

Answer 31

suprahyoid muscles…
geniohyoid
mylohyoid
digastrics
stylohyoid

Question 32

What are the muscles that depress the hyoid and larynx?

Answer 32

the infrahyoid muscles… 
sternohyoid
omohyoid
sternothyroid
thyrohyoid

The position of the larynx in the neck also affects the pitch of the voice (by changing the size of the resonating chamber).

Question 33

What are the Intrinsic Muscles of the Larynx?

Answer 33

act on a specific part of the larynx
alter the length or tension of the vocal folds
change the size or shape of the glottis.

Question 34

What pharyngeal arch are the intrinsic muscles of the larynx derived from?

Answer 34

4th-6th arches.

Question 35

Where is the cricothyroid? What is the action of the cricothyroid? What innervates the cricothyroid?

Answer 35

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

Question 36

What is the origin and insertion of the thyroarytenoid? What is the action of the thyroarytenoid? What is the innervation of the thyroarytenoid?

Answer 36

the internal aspect of the thyroid cartilage and inserts on the lateral border of the arytenoid cartilage.
a sphincter of the vestibule
innervated by the recurrent laryngeal nerve.

Question 37

What is the origin and insertion of the vocalis? What is the action of the vocalis? What is the innervation of the vocalis?

Answer 37

extends between the arytenoid cartilage and the internal aspect of the thyroid cartilage
its medial portion attaches to the vocal ligament.
action: adjust the tension of the vocal fold.
innervated by the recurrent laryngeal nerve.

Question 38

What is the origin and insertion of the posterior cricoarytenoid? What is the action of the Posterior Cricoarytenoid? What is the innervation of the Posterior Cricoarytenoid?

Answer 38

arises from the posterior surface of the cricoid cartilage and inserts into the muscular process of the arytenoid cartilage.
Action: short answer… abducts the vocal cords
Innervation: recurrent laryngeal nerve
Action: Long answer… pulls the muscular process of the arytenoid toward the midline. Since the arytenoid rotate on the cricoid cartilage, this causes the vocal process of the arytenoid to move laterally, thus causing the vocal ligaments to move apart.

Question 39

What is the origin and insertion of the Lateral Cricoarytenoid? What is the action of the Lateral Cricoarytenoid? What is the innervation of the lateral cricoarytenoid?

Answer 39

arises from the superior surface of the cricoid cartilage and inserts into the muscular process of the arytenoid cartilage.
Action: short answer… adducts the vocal cords
Innervation: recurrent laryngeal nerve
pulls the muscular process of the arytenoid cartilage laterally, causing the vocal process to move medially. Therefore, its action is to adduct the vocal fold. Lateral cricoarytenoid is innervated by the recurrent laryngeal nerve.

Question 40

the posterior cricoarytenoid and Lateral Cricoarytenoid – notice they oppose each other since they pull on the arytenoid cartilage from opposite locations.

Answer 40

the posterior cricoarytenoid and Lateral Cricoarytenoid – notice they oppose each other since they pull on the arytenoid cartilage from opposite locations.

Question 41

What is the origin and insertion of the transverse arytenoid? What is the action of the transverse arytenoid? What is the innervation of the transverse arytenoid?

Answer 41

extends between the two arytenoid cartilages.
Action: move the arytenoid cartilages closer together  close the posterior portion of the glottis.
innervated by the recurrent laryngeal nerve.

Question 42

What similar and different between the origin and insertion of the oblique arytenoid and the transverse arytenoid?

Answer 42

Similar  muscle fibers also extend from one arytenoid to the other
the difference  fibers of the oblique arytenoid are oriented in an oblique fashion rather than transverse.

Question 43

What is the aryepiglottic muscle?

Answer 43

Some of the fibers of the oblique arytenoid continue upward in the aryepiglottic fold and are called the aryepiglottic muscle.

Question 44

What is the action of the Oblique Arytenoid and the Aryepiglottic muscles?

Answer 44

Sphincters  reduce the size of the laryngeal inlet.

Question 45

What is the only muscle of the larynx innervated by the external laryngeal nerve? What are all the other muscles of the larynx innervated by?

Answer 45

cricothyroid muscle

recurrent laryngeal nerve

Question 46

What is the blood supply of the larynx?

Answer 46

the superior and inferior laryngeal arteries  branches of the superior and inferior thyroid arteries respectively.

Question 47

What is the course of the superior laryngeal artery?

Answer 47

travels through the hole in the thyrohyoid membrane with the internal laryngeal nerve.

Question 48

What is the course of the inferior laryngeal artery?

Answer 48

ascends along the trachea with the recurrent laryngeal nerve, and enters the larynx at the inferior border of the inferior pharyngeal constrictor muscle.