Lecture 16 - Applied Anatomy Of The Larynx

Question 1

What are the functions of the larynx?

Answer 1

Ventilation
Airway protection (main function)
Cough reflex
Phonation (production of sound)

Question 2

Go the last slide and label image 1:

Answer 2

1 = nasopharynx
2 = oropharynx
3 = soft palate
4 = Laryngopharynx
5 = trachea

Question 3

Where does the larynx begin?

Where does the larynx end?

Answer 3

Start = where laryngeal inlet communicates with Laryngopharynx

Ends = at C6 vertebral level at cricoid cartilage

Question 4

What are the piriform fossa?

Answer 4

The point in pharynx where food particles can get stuck preventing it from entering the trachea

Question 5

What bone is the larynx suspended from?

Answer 5

Hyoid Bone

Question 6

What is the membrane between the hyoid bone that attaches to the thyroid cartilage?

Answer 6

Thyrohyoid membrane

Question 7

What is the cartilage that attaches inferiorly to the thyroid cartilage?

Answer 7

Cricoid cartilage

Question 8

What si the name of the name of the membrane connecting the thyroid cartilage to the cricoid cartilage?

Answer 8

Cricothyroid cartilage

Question 9

What is the name of the membrane joining the cricoid cartilage to the trachea?

Answer 9

Cricotracheal membrane

Question 10

What is the order of structures from the hyoid bone inferiorly?

Answer 10

Hyoid bone
Thyrohoid membrane
Thyroid cartilage
Cricothyroid membrane
Cricoid cartilage
Cricotracheal membrane

Question 11

What special cartilages sit superiorly on the cricoid cartilage?

Answer 11

Arytenoid cartilages

Question 12

How can you palpate/determine where the Cricothyroid membrane is?

Answer 12

Palpate the Adam’s apple (laryngeal prominence of the Thyroid cartilage)
Its the soft and squishy area immediately inferior to it

Question 13

Why may you need to rapidly identify the Cricothyroid membrane?

Answer 13

For front of neck access for a Cricothyroidotomy

Question 14

What is a cricothryoidotomy?

Answer 14

Where a hole is made in the Cricothyroid membrane for emergency access to the airways underneath the vocal cords

Question 15

What cartilage does the epiglottis connect to?

Answer 15

Throid cartilage

Question 16

What i the joint called between the cricoid cartilage and the arytenoid cartilage called?

Answer 16

Cricoid-arytenoid cartilage

Question 17

What is the synovial joint which allows the thyroid cartilage to tilt forwards?

Answer 17

Thyroid-Cricothyroid joint

Question 18

What structure does the true vocal cord run from and to?

Answer 18

Runs from arytenoid cartilage to the inner surface of the thyroid cartilage

Question 19

What is the laryngeal inlet?

Answer 19

The start of the larynx

Question 20

What forms the margins of the laryngeal inlet?

Answer 20

The 2 aryepiglottic folds either side and the upper edge of the epiglottis

Question 21

What structures does the quadrangular membrane form?

Answer 21

Aryepiglottic fold

False vocal cord/vestibular fold

Question 22

What border of the quadrangular ligament forms the aryepiglottic fold?

Answer 22

Upper border

Question 23

What border of the quadrangular ligament forms the vestibular ligament/false vocal cord?

Answer 23

Lower border

Question 24

The upper border of what membrane forms the true vocal cord?

What cartilage does this have an edge running deep to?

Answer 24

Cricothyroid membrane

Thyroid cartilage

Question 25

What type of eof membrane lines the larynx?

Answer 25

Mucous membrane

Question 26

What are the 3 named regions of the larynx?

Answer 26

Supraglottis Glottis Infraglottis

Question 27

What is the Supraglottis of the larynx?

Answer 27

Most superior section From epiglottis to the false vocal cords/vestibular ligament

Question 28

What is the glottis of the larynx?

Answer 28

The narrowest part Where the true vocal cords can be found Between false cords and 1cm below true cords

Question 29

What is the Infraglottis of the larynx?

Answer 29

Below the glottis to lower boundary of the cricoid cartilage

Question 30

Go to the last slide and label image 2: (Larynx)

Answer 30

1 = Supraglottis 2 = glottis 3 = Infraglottis 4 = false cords/vestibular ligament 5 = true vocal cords 6 = epiglottis

Question 31

What type of epithelium lines most of hte larynx?

Answer 31

Pseudostratified Ciliated columnar epithelium (Respiratory epithelium)

Question 32

Which part of the larynx is NOT line by Pseudostratified Ciliated columnar epithelium?

Answer 32

True vocal cords

Question 33

What cells line the true vocal cords? Why?

Answer 33

Stratified squamous epithelium Exposed to lots of abrasive forces from the air

Question 34

How can we visualise the larynx?

Answer 34

Flexible nasendoscopy Endotracheal tube during intubation

Question 35

What is the name of the depression anterior to the epiglottis in the larynx?

Answer 35

Valecula

Question 36

What is the name of the depressions/fossae towards the posterior wall of the Laryngopharynx?

Answer 36

Piriform fossae

Question 37

Go to the last slide and label image 3:

Answer 37

1 = valecula 2 =aryepiglottic folds 3 = false vocal cords/vestibular folds 4 = true vocal cords 5 = arytenoid cartilage location 6 = Piriform fossae 7 = Rima glottidis

Question 38

What is the rima glottidis?

Answer 38

The opening between the true vocal cords

Question 39

How can you determine anatomical position from the rima glottidis?

Answer 39

The point of the rima glottidis points anterior

Question 40

Broadly what can we do to the larynx to prevent food entering the trachea during swallowing?

Answer 40

Alter shape and position of larynx in swallowing

Question 41

What are the 2 main functions of the intrinsic laryngeal muscles?

Answer 41

Alter size and shape of laryngeal inlet Alter tension and position of the true vocal cords

Question 42

What do the intrinsic laryngeal muscles act on to vary the position of the true vocal cords to control pitch of voice/tension in cords?

Answer 42

Arytenoid cartilages

Question 43

Where are the intrinsic laryngeal muscles which contract narrowing the laryngeal inlet and flattening the epiglottis?

Answer 43

Aryepiglottic folds

Question 44

What nerves supply the majority of the intrinsic laryngeal muscles? What cranial nerve is this a branch of?

Answer 44

Recurrent laryngeal nerves Branch from the Vagus Nerve (X)

Question 45

During swallowing, how does the larynx act to protect the airways from food and fluid?

Answer 45

Epiglottis flattens Aryepiglottic folds contract narrowing laryngeal inlet Food caught in the piriform fossae

Question 46

What bone moving is important in protecting the airways in swallowing?

Answer 46

Hyoid Bone

Question 47

What muscles move the hyoid bone during swallowing? What muscle stabilises the hyoid bone?

Answer 47

Suprahyoid muscles Infrahyoids

Question 48

How do the suprahyoid muscels move the hyoid bone?

Answer 48

Move antero-superiorly

Question 49

How does movement of the hyoid bone Antero-superiorly by the suprahyoid muscles help protect the airway from food and fluid?

Answer 49

Hyoid moves the larynx up and off the pharynx this directs any food/fluid collected in the piriform fossa into the open pharynx

Question 50

The movement of what cartilage opens and closes the true vocal cords/rima glottidis?

Answer 50

Arytenoid cartilage

Question 51

What action would a person be doing if their true vocal cords were firmly adducted and the laryngeal inlet narrowed?

Answer 51

Swallowing (Protecting the trachea)

Question 52

What action would a person be doing if their true vocal cords were abducted and the laryngeal inlet open?

Answer 52

Breathing/ventilating

Question 53

What is the position of the true vocal cords during phonation/speech? How does this produce speech?

Answer 53

They are closely adducted but expired air can be forced through Vocal cords vibrate along their length setting up vibrations int he air

Question 54

What happens to the vocal cords in the cough reflex?

Answer 54

Inspired and fill lungs with air Vocal cords ADduct Expiraotry muscles contract Intra thoracic pressure increases Vocal cords then suddenly ABduct allowing explosive outflow of air

Question 55

What muscles control the pitch of the voice/tension in the Vocal cords?

Answer 55

Cricothyroid muscles

Question 56

How do the Cricothyroid muscels control pitch of the voice?

Answer 56

Controls the tilt of the thyroid cartilage on the cricoid cartilage controlling how taut it is Vocal cords taut = high pitch Vocal cords less taut = low pitch

Question 57

What nerve innervates the Cricothyroid muscles therefore controlling pitch? What is this a branch of?

Answer 57

External branch of superior laryngeal nerve Branch of the Vagus nerve (X)

Question 58

What artery is the external branch of teh superior laryngeal nerve associated with?

Answer 58

Superior thyroid artery

Question 59

What can happen if the external branch of the superior laryngeal nerve is damaged in a thyroid surgery?

Answer 59

Hoarseness of voice when trying for higher pitched sounds

Question 60

What are the 2 main nerves branching from the vagus nerve supplying the larynx?

Answer 60

Superior laryngeal nerve Recurrent laryngeal nerve

Question 61

What are the 2 branches from the superior laryngeal nerve?

Answer 61

Internal branch External branch

Question 62

What is the function of the internal branch of the superior laryngeal nerev?

Answer 62

Sensation to Supraglottis and glottis (+true vocal cords)

Question 63

What is the function of the external branch of the superior laryngeal nerve?

Answer 63

Motor function to Cricothyroid muscles (control pitch of voice)

Question 64

What is the function of the recurrent laryngeal nerve?

Answer 64

Motor function to intrinsic laryngeal muscles (moving vocal cords) Sensory to Infraglottis

Question 65

What is the route of the left recurrent laryngeal nerve?

Answer 65

Branches from the left vagus nerve and loops under the arch of aorta to where it then ascends upwards to the larynx

Question 66

What is the route of the right recurrent laryngeal nerve?

Answer 66

Branches from right vagus nerve It then loops under the right subclavian artery to where it then ascends up to the larynx

Question 67

What type of surgery puts the external laryngeal nerve at risk?

Answer 67

Thyroid surgery since it runs closely with the superior thyroid artery

Question 68

What does injury to the recurrent laryngeal nerve cause?

Answer 68

Vocal cord palsy (needed to move the true vocal cords)

Question 69

How does a unilateral recurrent laryngeal nerve. Injury present?

Answer 69

Hoarse voice Weak/ineffective cough Cant fully abduct or Adduction cords

Question 70

If the right recurrent laryngeal nerve is damaged what would the position of the right vocal cord be?

Answer 70

Halfway between adducted and abducted (PARAMEDIAN position)

Question 71

Why is a bilateral recurrent laryngeal nerve injury life threatening?

Answer 71

Both vocal cords assume resign gparamedian position so rima glottis NARROW Significant airway obstruction Need emergency surgical airway access below Vocal cords Cricothryoidotomy

Question 72

What is laryngitis?

Answer 72

Inflammation of larynx often involving vocal cords

Question 73

Why do you often lose your voice with laryngitis?

Answer 73

Cant create a full seal of the vocal cords due to the inflammation

Question 74

How dangerous is epiglottis?

Answer 74

Very dangerous since significant risk to airway

Question 75

What causes laryngeal oedema?

Answer 75

Allergic reaction or swallowed foreign body

Question 76

What is a laryngeal nodule?

Answer 76

Benign lump in larynx

Question 77

What type of tumour are laryngeal cancers normally?

Answer 77

Squamous cell carcinoma on vocal cord

Question 78

What is Croup?

Answer 78

Viral infection of subglottic region and laryngeal mucosa causing inflammation oedema

Question 79

Who does croup usually affect?

Answer 79

Young children/infants

Question 80

What is epiglottitis?

Answer 80

Inflammation/infection of the supraglottis

Question 81

What are the 3 most likely causative pathogens for epiglottitis?

Answer 81

Haemophilus influenzae B Streptococcus pneumoniae Moraxella catarrhalis

Question 82

Go to the last slide and label the larynx: (4)

Answer 82

1 = epiglottis 2 = laryngeal inlet 3 = false vocal cord 4 = true vocal cord 5 = infraglottis/subglottic region 6 = trachea 7 = aryepiglottic fold 8 = hyoid bone 9 = thyroid cartilage 10 = cricoid cartilage 11= lateral lobe of thyroid gland

Question 83

What is the afferent and efferent limb of the gag reflex?

Answer 83

Afferent = Glossopharyngeal Efferent = vagus

Question 84

What structure does the left recurrent laryngeal nerve runn close to?

Answer 84

Superior thyroid artery

Question 85

What symptoms occur if the external branch of superior laryngeal nerve is injured and why?

Answer 85

Hoarseness with high pitch Innervates the cricothyroid muscles which control tone of vocal cords (angle of thyroid cartilage on cricoid cartilage)

Question 86

What are a couple causes of voice hoarseness?

Answer 86

Laryngeal cancers Pancoast tumours