51 - Larynx and Laryngopharynx

Question 1

Boundaries of the larynx

Answer 1

Epiglottis

C6/lower boarder of the cricoid cartilage

Question 2

Where does the larynx open into the pharynx?

Answer 2

Posteriorally

Question 3

Laryngeal skeleton

Answer 3

Hyoid bone most superior
Thyroid cartilage in middle
Cricoid cartilage most inferior

Question 4

Membrane linking the hyoid bone and thyroid cartilage

Answer 4

Thyrohyoid membrane

Question 5

Shape of the thyroid cartilage

Answer 5

Anteriorally is angle (Adam’s apple).
Laminae laterally
Projections upwards and downwards from posterior aspect.
Open posteriorly (forms the laryngeal inlet)

Question 6

Shape of the cricoid cartilage

Answer 6

Entirely closed.
Short anterior arch.
Tall posterior lamina.
Arytenoid cartilages sit on posterior aspect.

Question 7

Processes from arytenoid cartilages

Answer 7

Vocal processes project into lumen of cricoid.

Muscular processes project laterally.

Question 8

Arytenoid processes

Answer 8

Sit on postero-lateral aspect of cricoid cartilage.
Can swivel, allowing vocal ligaments to move.
Vocal and muscular processes.
Can come together to adduct vocal ligaments

Question 9

What does the epiglottic cartilage attach to?

Answer 9

Thyroid cartilage (anterior wall)

Question 10

Vibration of what causes sound production for speech?

Answer 10

Vocal ligament

Question 11

Attachments of the vocal ligaments

Answer 11

Vocal process of arytenoid processes.

Attaches to posterior aspect of the angle of thyroid, inferior to where epiglottic cartilage attaches.

Question 12

Fold of mucosa above vocal ligament

Answer 12

Vestibular fold (false vocal ligament)

Question 13

Fold of mucosa over vocal ligaments

Answer 13

Vocal fold (true vocal cord)

Question 14

Arrangement of vocal ligaments in inspiration and phonation

Answer 14

Adducted for phonation, abducted for breathing

Question 15

Muscles that alter position of vocal ligaments

Answer 15

Intrinsic muscles

Question 16

Intrinsic muscles of the larynx

1 - 6

Answer 16

1) Posterior cricoarytenoid
2) Transverse and oblique arytenoids
3) Lateral cricoarytenoid
4) Cricothyroid
5) Thyroarytenoid
6) Vocalis

Question 17

Role of posterior cricoarytenoid

Answer 17

Abducting vocal ligaments.

Only intrinsic muscle that abducts vocal ligaments.

Question 18

Role of lateral cricoarytenoid

Answer 18

Adducts vocal ligaments

Question 19

Role of cricothyroid muscle

Answer 19

Pulls angle of thyroid forwards.

Stretches vocal ligaments, increases pitch of phonated note

Question 20

Two main nerve supplies of muscles of larynx

Answer 20

Superior laryngeal nerve (from above)
Recurrent laryngeal nerve (from below)
Both are branches of the vagus

Question 21

What does the recurrent laryngeal nerve innervate in the larynx?

Answer 21

All intrinsic muscles of larynx except cricothyroid muscle.

Question 22

What does the superior laryngeal nerve innervate in the larynx?

Answer 22

Cricothyroid muscle.

Question 23

Effect of damaging recurrent laryngeal nerve?

Answer 23

Can’t abduct or adduct vocal ligament on the side of the damaged nerve.
Leads to a hoarse voice and stridor.

Question 24

Effect of damaging superior laryngeal nerve

Answer 24

Can’t produce high sounds vocally

Question 25

Sensory innervation above the vocal ligaments

Answer 25

Internal laryngeal supplies sensory to mucosa

Question 26

Sensory innervation below the vocal ligaments

Answer 26

Recurrent laryngeal

Question 27

Blood supply of the larynx

Answer 27

Highly vascular.
Comes from thyroid vessels above and below.
These vessels also supply thyroid gland.

Superior thyroid artery is a branch of the external carotid.
Inferior thyroid artery is a branch of the subclavian.

Question 28

Cricothyroid membrane puncture vs tracheotomy

Answer 28

Tracheotomy can lead to rupture of thyroid blood vessels, leading to bleeding directly into airway. Only do this if under controlled circumstances, where you can find and avoid blood vessels.

Puncturing cricothyroid membrane is much safer, as there are fewer blood vessels here.

Question 29

Things that protect laryngeal inlet

Answer 29

Epiglottis blocks top of laryngeal inlet.

Larynx ascends when you swallow, ascending around epiglottis, giving a better seal.

Question 30

What stops fluids from entering laryngeal inlet?

Answer 30

Piriform recesses.

Paths for fluids to flow through, around laryngeal inlet.

Question 31

What form the afferent arc of the gag reflex?

Answer 31

Glossopharyngeal nerve (pharyngeal branches)

Question 32

What innervates most of the pharynx (sensory)?

Answer 32

CNIX

Question 33

What helps CNIX innervate nasopharynx (sensory)?

Answer 33

Trigeminal nerve (pharyngeal fibres of maxillary nerve)

Question 34

What helps CNIX innervate oropharynx (sensory)?

Answer 34

Nothing. Only glossopharyngeal nerve.

Question 35

What helps CNIX innervate the laryngopharynx (sensory)?

Answer 35

Vagus (internal laryngeal nerve)

Question 36

What innervates the mucosa of the middle ear?

Answer 36

Glossopharyngeal nerve (can refer pain to the palatine tonsils, as share nerve supply)

Question 37

What innervates muscles of pharynx, except for stylopharyngeus (motor)

Answer 37

Pharyngeal branches of vagus

Question 38

What innervates stylopharyngeus (motor)?

Answer 38

Glossopharyngeal

Question 39

Mechanism of swallowing (think about the muscles that do each of these actions)
1-8

Answer 39

1. Bolus shaped and pushed by tongue to palate.
2. Soft palate descends and palatal arches are approximated to grip and push the bolus into the oropharynx.
3. Soft palate elevated and tightened to prevent bolus entering nasal cavity.
4. Larynx and pharynx elevated to bring bolus closer to oesophagus.
5. Laryngeal inlet closed to prevent bolus from entering the trachea.
6. Bolus is pushed down the oropharynx and over the epiglottis.
7. Bolus forced down through laryngopharynx and into oesophagus.
8. Larynx depressed to return to normal position (mainly by elastic recoil).