24 - Larynx

Question 1

What is the function of the larynx?

Answer 1

• allows passage of air to trachea
• protective sphincter of airway
• organ of phonation

Question 2

Where is the larynx located?

Answer 2

• C3-C6
• tip of epiglottis to cricoid cartilage

Question 3

Describe the openings of the larynx.

Answer 3

• opens superiorly into larygnopharynx via laryngeal inlet
• opens inferiorly and is continuous with trachea

Question 4

What are the cartilages of the larynx?

Answer 4

• 9 total
• epiglottis
• thyroid
• cricoid
• arytenoid x2
• cuneiform x2
• corniculate x2

Question 5

What type of cartilage makes up the larynx?

Answer 5

• all hyaline cartilage
• except for epiglottis made up of elastic

Question 6

How does the cricoid cartilage differ from the other cartilage of the larynx?

Answer 6

Only complete ring

Question 7

Where is the superior thyroid notch located?

Answer 7

Sits superior to the laryngeal prominence, formed by the thyroid cartilage

Question 8

Describe the cricothyroid joint.

Answer 8

• synovial joint formed by the articulation of the cricoid and thryoid cartilage
• allows for gliding and rotation of larynx
• affect pitch of voice

Question 9

Describe the epiglottis.

Answer 9

• leaf shaped elastic cartilage
• covered in mucosa
• attached to back of thyroid cartilage by thryo-epiglottic ligament
• attached to the hyoid bone by hyo-epiglottic ligament

Question 10

What is the function of the epiglottis?

Answer 10

• boundary between larynx and laryngopharynx
• protects airway from fluids and bolus

Question 11

Describe the arytenoid cartilage.

Answer 11

• pyramidal shaped hyaline cartilage
• articulates with corniculate (superiorly) and cricoid cartilage (inferiorly)
• apex forms site for aryepiglottic fold attachment
• sits superior to cricoid cartilage

Question 12

What are the extrinsic ligaments and membranes of the larynx?

Answer 12

• thyrohyoid membrane
• median and lateral thyrohyoid ligaments
• ligaments are formed by thickening of the membrane anteriorly and posteriorly respectively

Question 13

What cartilage is found within the lateral thryohyoid ligament?

Answer 13

Triticeal cartilage

Question 14

What are the intrinsic ligaments and membrane of the larynx?

Answer 14

• quadrangular membrane
• cricothyroid ligament (criciovocal membrane)
• vocal ligament

Question 15

Describe the quadrangular membrane.

Answer 15

• extends from arytenoid cartilage to thyroid cartilage to the epiglottis
• has free inferior margin which forms vestibular ligament

Question 16

Describe the cricothyroid ligament.

Answer 16

• membrane extends from cricoid to arytenoid to thyroid cartilage
• thickens anteriorly to form median cricothryoid ligament

Question 17

Describe the vocal ligament.

Answer 17

• superior free edge of cricothryoid ligament
• forms aryepliglottic fold

Question 18

What are the laryngeal folds?

Answer 18

• mucosa membrane that forms over the free edges of the intrinsic ligaments of the larynx
• aryepliglottic
• vestibular
• vocal

Question 19

Describe the aryepligottic fold.

Answer 19

• forms over the superior free edge of the quadrangular membrane
• forms the laryngeal inlet
• protective sphincter of larynx

Question 20

Describe the vestibular folds.

Answer 20

• forms over inferior free edge of quadrangular membrane (vestibular ligament)
• protective function

Question 21

Describe the vocal folds.

Answer 21

• true vocal cords
• forms over superior free edge of cricithyroid cartilage (vocal ligament)

Question 22

What is the rima glottidis?

Answer 22

Opening/space between vocal cords

Question 23

What are the extrinsic muscles of the larynx?

Answer 23

• infrahyoid muscles
• suprahyoid muscles
• stylopharyngeus

Question 24

What is the role of the extrinsic laryngeal muscles?

Answer 24

To raise/depress the larynx

Question 25

What are the intrinsic laryngeal muscles?

Answer 25

- posterior cricoarytenoid - lateral cricoarytenoid - transverse arytenoid - oblique arytenoid - thryoarytenoid - cricothryoid - vocalis

Question 26

What are the functions of the intrinsic laryngeal muscles?

Answer 26

- open/close rima glottidis - alter tension of vocal folds - open close laryngeal inlet

Question 27

What muscles act to open/close the rima glottidis?

Answer 27

- abductors/adductors - posterior cricotarytenoid abducts vocal folds (opens) - transverse arytenoid and lateral cricoarytenoid adduct (closes)

Question 28

Describe the location of the transverse arytenoid.

Answer 28

Runs transversely across the arytenoid cartilage

Question 29

Describe the location of the lateral cricoarytenoid muscle.

Answer 29

Attaches from the lateral aspect of the cricoid cartilage to the arytenoid cartilage, running obliquely

Question 30

Describe the location of the posterior cricoarytenoid muscle.

Answer 30

Runs from the midline of the posterior aspect of the cricoid cartilage to the lateral aspect of the arytenoid cartilage

Question 31

What muscles act to alter the tension of the vocal folds?

Answer 31

- tensors/relaxers - cricothyroid lengthens the vocal folds - thyroarytenoid relaxes vocal folds (vocalis is the upper part)

Question 32

What effect does lengthening the vocal folds have on phonation?

Answer 32

Increased tension = higher pitch

Question 33

What effect does shortening the vocal folds have on phonation?

Answer 33

Reduced tension = lower pitch

Question 34

Describe the location of the thyroarytenoid muscle.

Answer 34

Runs transversely from the posterior of the thyroid cartilage to the arytenoid cartilage

Question 35

Describe the location of the cricothyroid muscle.

Answer 35

Straight and oblique part on the anterior aspect of the cricoid cartilage which attach to the thyroid cartilage

Question 36

What muscles act to open/close laryngeal inlet?

Answer 36

- oblique arytenoid muscle, acts a purse string (closure) - extrinsic muscles also contribute - opening via descent of larynx and elastic recoil

Question 37

Describe the location of the oblique arytenoid muscles.

Answer 37

- form a cross as they run obliquely from the lateral aspect of the arytenoid cartilage, cross at the midline and continue to other lateral side - continue superiorly as the aryepiglottic part

Question 38

What is the motor innervation of the larynx?

Answer 38

- all muscles supplied by recurrent laryngeal nerve - EXCEPT cricothyroid supplied by external branch of superior laryngeal nerve - both are branches of CN X

Question 39

What is the sensory innervation of the larynx?

Answer 39

- sensation superior to vocal fold supplied by internal branch of superior laryngeal nerve - sensation inferior to vocal folds supplied by the recurrent laryngeal nerve - both are branches of CN X

Question 40

Describe the shape of the rima glottidis during normal breathing.

Answer 40

- quiet respiration - vocal and vestibular folds abducted (open) - rima glottidis triangular in shape - vestibule open

Question 41

Describe the shape of the rima glottidis during forced inspiration.

Answer 41

- opened wider by the cricoarytenoid muscle, wider based triangular - vestibule open

Question 42

Describe the shape of the rima glottidis during phonation.

Answer 42

- vocal cords adducted - vestibule open - rima glottidis is closed, air forced through causing vibration

Question 43

Describe the shape of the rima glottidis during effort closure.

Answer 43

- vocal and vestibular folds adducted (closed) - rima glottidis and vestibule closed - valsalva manoeuvre

Question 44

What is the valsalva manoeuvre used for?

Answer 44

- when lifting weights - bowel moments - equalising pressure in the middle ear