Larynx

Question 1

What is the function of the larynx? How does it achieve this?

Answer 1

Allows air passage in and out of trachea, prevents foreign bodies entering airway, and is the organ of phonation

Airway protected by a sphincter and phonation achieved by vocal folds

Question 2

What type of cartilage is the larynx?

Answer 2

All hyaline cartilage minus the epiglottis which is elastic

Question 3

What cartilage can be seen from the posterior view but not the anterior?

Answer 3

Arytenoid, corniculate and cuneiform cartilage

Question 4

Describe the shape of the epiglottis and its function

Answer 4

Leaf shaped cartilage attached to the thyroid cartilage

It has no function in respiration or phonation but functions to protect the airway from bolus

Question 5

Describe the structure of the thyrohyoid membrane

Answer 5

Attaches from thyroid cartilage to hyoid bone.

Laterally has lateral thyrohyoid ligaments and anteriorly has a median thyrohyoid ligament

Also has an aperture for internal branch of superior laryngeal nerve and artery

Question 6

Label the associated structures

Answer 6

Quadrangular membrane

Cricoid cartilage

Vocal ligament (superior free edge of cricothyroid ligament)

Vestibular ligament (inferior free edge quadrangular membrane)

Cricothyroid ligament / cricocervical membrane

Question 7

What forms the protective sphincter of the larynx?

Answer 7

Aryepiglottic fold that runs over the superior free edge of quadrangular membrane

Vestibular folds fold over vestibular ligament

Vocal folds (true vocal vords) formed over vocal ligament

Rims glottidis = the space between vocal folds

Question 8

What are the function of the intrinsic laryngeal muscles and which does which?

Answer 8

Open of close rima glottidis (adductors or abductors)

Alter tension of vocal folds (tensors / relaxers) (true vocal cords over vocal ligament)

Open or close laryngeal inlet (sphincter muscles)

Question 9

What muscle opens the rima glottidis and which closes?

Answer 9

Opening = posterior cricoarytenoid muscle

Close = transverse arytenoid muscle and lateral cricoarytenoid muscle

Question 10

How is pitch of voice altered?

Answer 10

Lengthened folds = increased tension = higher pitch
- cricothyroid muscle

Shortened folds = less tension = deeper voice
- thyroarytenoid muscle

Question 11

How is the laryngeal inlet opened or closed?

Answer 11

Closing = oblique arytenoid muscle

Opening = descent of larynx and pharynx mainly by elastic recoil

Question 12

What is the sensory nerve supply of the larynx?

Answer 12

Above vocal folds = internal superior laryngeal nerve

Below = recurrent laryngeal nerve

These are branches of vagus

Question 13

How is the larynx involved in breathing?

Answer 13

Forced inspiration = rima glottidis is forcefully and more widely opened by posterior cricoarytenoid muscle

Quiet inspiration = vocal and vestibular folds abducted and triangular open rima glottidis is present

Question 14

How is speech produced in the larynx?

Answer 14

Vocal folds addicted

Rima glottidis closed and air forced through causing vibration

Vocal fold length and tension altered to determine pitch

Question 15

What is effort closure? How is it achieved along with swallowing?

Answer 15

Effort closure is needed for things such as heavy lifting

Vocal and vestibular folds addicted

Rima glottidis closed

Vestibule also closed