Anatomy Of The Larynx

Question 1

Functions of the larynx

Answer 1

• Ventilation
• Airway protection: prevents flood/fluids entering airways
• Cough reflex: rapidly expel anything inadvertently entering airways
• role in sound production (not a primary function)

Question 2

When does the larynx begin and end?

Answer 2

• begins at laryngeal inlet
• ends at cricoid cartilage C6

Question 3

What part of the pharynx is posterior to the larynx?

Answer 3

Laryngopharynx

Question 4

What are the piriform fossae?

Answer 4

A small recess on either side of side of laryngeal inlet

Question 5

Anatomical relationship between the larynx + the hyoid

Answer 5

Larynx is suspended from the hyoid bone by the thyrohyoid membrane

Question 6

What connects the cricoid cartilage to the thyroid cartilage?

Answer 6

Cricothyroid membrane

Question 7

What are the arytenoid cartilages?
Location

Answer 7

Sit on the posterior portion of the cricoid cartilage

Question 8

What is a cricothyroidotomy?
Example of why you may need it

Answer 8

Incision made through skin + cricothyroid membrane below the vocal cords to provide airway to patient in an emergency
e.g. severe swelling of vocal cords

Question 9

What are the margins of the laryngeal inlet

Answer 9

2 aryepiglottic folds
Upper edge of epiglottis

Question 10

What are the aryepiglottic folds?

Answer 10

• Attach epiglottis to arytenoid cartilages
• (The free upper border of the quadrangular membrane)

Question 11

What is the false vocal cord formed by?

Answer 11

free lower border of the quadrangular membrane

Question 12

What are the aryepiglottic fold formed from?

Answer 12

free upper border of the quadrangular membrane

Question 13

What forms the true vocal cords?

Answer 13

Free upper border of cricothyroid membrane

Question 14

How is the larynx internally divided?

Answer 14

• Supraglottis: epiglottis up to + including false vocal cords
• Glottis: false vocal cords to true vocal cords (narrowest part)
• Infraglottis: below true vocal cord to lower boundary of cricoid C6

Question 15

What type of epithelium lines the larynx?
What is the exception

Answer 15

• pseudostratified ciliated columnar epithelium (respiratory epithelium)
• true vocal cords > stratified squamous epithelium

Question 16

What type of epithelium lines the true vocal cords?

Answer 16

Stratified squamous epithelium

Question 17

What two ways can you view the larynx?

Answer 17

Flexible nasendoscopy
Intubation

Question 18

What must be viewed for laryngoscopic view during intubation?

Answer 18

• Vocal cords must be viewed
• Placement of endotracheal tube into infraglottic region

Question 19

Another name for false vocal chords

Answer 19

Vestibular fold

Question 20

Another name for the true vocal chords

Answer 20

Vocal folds

Question 21

What is the rima glottidis?

Answer 21

Opening between the true vocal chords

Question 22

How to orientate yourself when looking at the larynx

Answer 22

Point of rima glottidis points forwards (towards epiglottis)

Question 23

Functions of the intrinsic laryngeal muscles

Answer 23

• alter size + shape of laryngeal inlet
• alter tension in + position of true vocal chords

Question 24

How do the intrinsic laryngeal muscles alter the size + shape of laryngeal inlet?

Answer 24

Muscles within aryepiglottic folds contract narrowing inlet + flattens epiglottis

Question 25

How do the intrinsic laryngeal muscles alter the the tension in + position of the true vocal cords?

Answer 25

Muscles act on arytenoid cartilages to vary position of true vocal cords

Question 26

Innervation of the intrinsic laryngeal muscles

Answer 26

**Recurrent laryngeal nerve** (From vagus nerve X) (Except cricothyroid muscle)

Question 27

What is the recurrent laryngeal nerve a branch of?

Answer 27

Vagus nerve X

Question 28

How does the hyoid bone move during swallowing? What does this do?

Answer 28

- Moved antero-superiorly by suprahyoid muscles - Moves position of larynx up + off the pharynx - Food/fluid directed into open pharynx

Question 29

What positions can the vocal cords be in?

Answer 29

**ADducted** (closed) **ABducted** (open)

Question 30

What position are the vocal cords in when swallowing?

Answer 30

Firmly ADducted (closed)

Question 31

What position are the vocal cords in when breathing?

Answer 31

ABducted (open)

Question 32

What position are the vocal cords in during phonation (talking)?

Answer 32

- ADucted - But expired air can be forced through - Vocal cords vibrate > sound waves

Question 33

What does the variation of tension of the vocal cords determine?

Answer 33

Pitch

Question 34

Tension of true vocal cords in high pitched vs low pitched sounds

Answer 34

**high pitched**: vocal cords taut **low pitched**: vocal cords less taut

Question 35

Outline the process of coughing What is the position of the vocal cords when coughing?

Answer 35

- inspire + fill lungs with air - **vocal cords ADduct** - expiratory muscles contract - intrathoracic pressure builds - **vocal cords suddenly ABducts** - explosive outflow air

Question 36

What muscle changes the tension of the true vocal cords (therefore pitch)?

Answer 36

Cricothyroid muscle

Question 37

Action of cricothyroid muscle

Answer 37

- tilts thyroid cartilage forwards of cricoid - increases tension in vocal cords - higher pitch made

Question 38

Innervation of cricothyroid muscle

Answer 38

External branch of superior laryngeal nerve (Branch of vagus X)

Question 39

Motor and sensory supply of the recurrent laryngeal nerve

Answer 39

- **motor**: intrinsic laryngeal muscles - **sensory**: infraglottis

Question 40

Supply of the external branch of superior laryngeal nerve

Answer 40

Motor innervation to cricothyroid muscle

Question 41

Supply of internal branch of superior laryngeal nerve

Answer 41

Sensory innervation to supraglottis + glottis

Question 42

Route of left and right recurrent laryngeal nerve

Answer 42

- **left**: under arch of aorta - **right**: under right subclavian artery

Question 43

What is the paramedian position? When does it occur?

Answer 43

- Vocal cords held halfway between full ADduction + full ABduction - paralysed vocal cord

Question 44

Symptoms of injury to unilateral recurrent laryngeal nerve

Answer 44

Hoarse voice Weak/ineffective cough

Question 45

Complication of bilateral recurrent laryngeal nerve injury

Answer 45

- Both vocal cords assume paramedian position - Narrows rima glottis - Significant airway obstruction

Question 46

What is laryngitis?

Answer 46

Inflammation of larynx Often involves vocal cords

Question 47

What is croup?

Answer 47

- common childhood infection - causes barking cough + rasping sound when breathing

Question 48

A child presents with a barking/seal like cough, what is the most likely diagnosis?

Answer 48

Croup

Question 49

What is epiglottitis?

Answer 49

**Inflammation of the epiglottis + supraglottis** Significant risk to airway

Question 50

What conditions can affect the larynx?

Answer 50

- laryngitis - croup - epiglottis - laryngeal oedema - laryngeal nodule - laryngeal cancer

Question 51

Sensory innervation to the larynx

Answer 51

- **internal branch of superior laryngeal nerve**: supraglottis + glottis - **recurrent laryngeal nerve**: infraglottis

Question 52

What type of cartilage is the epiglottis composed of?

Answer 52

Elastic

Question 53

What is the most common cause of epiglottitis?

Answer 53

Haemophilus influenzae B

Question 54

What is the valleculae?

Answer 54

The space between the posterior tongue + epiglottis