Sem 2 - Z (1) - Larynx - Cartilages, Membranes/ligaments, Vocal folds, Intrinsic muscles, Neurovasculature, Lymph

Question 1

The larynx is located deep to the strap muscles and thyroid gland but superficial to the laryngopharynx What type of joints exist in the larynx?

Answer 1

Synovial plane joints exist between the cricoid and thryoid cartilages - cricothyroid joint

Synovial plane joints exist between the cricoid and arytenoid cartilages - cricoarytenoid cartilages

Question 2

The thyroid cartilage is composed of two laminae which meet anteriorly in the middle to form what? What do these laminae extend posteriorly as?

Answer 2

The laminae of the thyroid cartilage meets in the middle to form the laryngeal prominence (Adam’s apple) The laminae extend posteriorly in a superior and inferior direction forming the superior and inferior horns respectively

Question 3

What do the superior and inferior horns of the thyroid cartilage connect to?

Answer 3

The superior horns of the thyroid cartilage connect to the hyoid bone via the lateral thyrohyoid ligaments The inferior horns of the thyroid cartilage have a facet to connect to the cricoid cartilage (synovial plane joints)

Question 4

How are the superior and inferior tubercles of the thyroid cartilage connected? What attaches along this line?

Answer 4

The superior and inferior tubercles of the thyroid cartilage are connected by the oblique line of the cartilage

The sternothryoid, thyrohyoid and inferior constrictor muscle all attach to this oblique line

Question 5

State what each number is labelling

Answer 5

• 1. Laryngeal prominence
• 2. Superior thyroid notch
• 3. Superior thyorid horn
• 4. Superior thyroid tubercle
• 5. Inferior thyroid horn
• 6. Inferior thyroid tubercle

Sternothyroid, thyrohyoid and inferior constrictor all attach to the oblique line

Question 6

Is the cricoid cartilage a complete or incomplete ring? What shape is the cricoid cartilage said to resemble?

What vertebral level is this cartilage found at? What are the two parts of the cricoid cartilage?

Answer 6

The cricoid cartilage is a complete ring of hyaline cartilage said to resemble a signet ring

It is found at the C6 vertebral level We have the cricoid arch anteriorly and the lamina posteriorly

Question 7

What is the difference in location of the cricoid facets for the arytenoid and thyroid cartilages?

Answer 7

The facets for the arytenoid cartilages are located superiorly on the lamina

The facets for the thyroid cartilage are located inferiorly and laterally on the lamina

Question 8

What shape are the arytenoid cartilages and what do they sit on?

Answer 8

The arytenoid cartilages are pyramidal shaped structures which sit on top of the cricoid cartilage

Question 9

The arytenoid cartilages consist of an apex, base, three sides and two processes

• What does the apex articulate with?
• What does the base articulate with?
• Which aspect of the base can the vocal and muscular process be found?

Answer 9

• The apex articulates with the corniculate cartilage superiorly
• The base articulates with the superior border of the lamina of the cricoid cartilage
• The vocal processes are located at the anterior aspect of the base The muscular processes are located at the lateral aspect of the base

Question 10

What muscles attach to the muscular processes of the arytenoid cartilages?

What attaches to the vocal processes of the arytenoid cartilage? Where do the vestibular folds attach?

Answer 10

The posterior and lateral cricoarytenoid muscles and the oblique arytenoid muscles will attach to the muscular processes

The vocal ligament (true vocal cords) attaches to the vocal processes

• The vestibular folds (false vocal cords) attach to the anterolateral surface of the arytenoid cartilage superior to vocal ligament

Question 11

Where do the corniculate cartilages attach and what attaches here?

Where are the cuneiform cartilages found and what is their function?

Answer 11

The corniculate cartilages attach to the apices of the arytenoid cartilages and serve as an attachment for the aryepiglottic folds

The cuneiform cartilages are found within the aryepiglottic folds and act to strengthen the folds

Question 12

What type of cartilage is the epiglottis? How does it function during swallowing?

Answer 12

The epiglottis is made up of elastic cartilage - during swallowing the epiglottis moves posteriroly closing off the entry to the larynx

Question 13

What does the epiglottis form connections with anteriorly and laterally?

Answer 13

Anteriorly the epiglottis forms connections with the body of the hyoid bone and posterior surface of the thyroid cartilage

Laterally the epilgottis forms connections with the arytenoid cartilages via the aryepiglottic folds

Question 14

The mucous membrane covering of the epiglottis is reflected onto the posterior surface of the tongue forming different folds What are these folds known as?

Answer 14

The median glossoepiglottic fold and the lateral glossepiglottic folds (x2)

Question 15

What are the ligament connecting the epiglottis to the hyoid bone and thyroid cartilage known as?

Answer 15

Hyoepiglottic and thyroepiglottic ligaments - attach from anterior of epiglottis to the body of the hyoid bone and the posterior surface of the thyroid cartilage respectively

Question 16

Thyrohyoid membrane – Spans between the superior aspect of the thyroid cartilage and the hyoid bone.

• What does it thicken anteromedially and posterolaterally to form?
• What neurovascular strucutres pierce the thyrohyoid membrane?

Answer 16

Thyrohyoid membrane thickens anteromedially to form the median thyrohyoid ligament and thickens posterolaterally to form the lateral thyrohyoid ligaments

The thyrohyoid membrane is pierced laterally by the superior laryngeal vessels and the internal laryngeal nerve

Question 17

The cricothyroid membrane attaches the cricoid cartilage to the thyroid cartilage anteriorly, what does it attach to posteriorly? What is the anteromedial thickening of the membrane known as?

What connects the cricoid cartilage to the trachea?

Answer 17

Cricothyroid membrane originates from the cricoid cartilage and extends superiorly to attache to the thyroid cartilage anteriorly and arytenoid cartilages posteriorly

• The anteromedial thickening is the median cricothyroid ligament

Cricoid cartilage connected to trachea by the cricotracheal ligament

Question 18

What is the free upper border of the cricothyroid membrane known as?

Answer 18

The free upper border of the cricothyroid membrane is known as the vocal ligaments (true vocal folds)

Question 19

Describe how the false vocal folds are formed and what their proper name is?

Answer 19

The aryepiglottic fold is a lateral connection from the epiglottis to arytenoid cartilages

• From this fold extends downwards a membrane known as the quadrangular membrane
• The free inferior edge of the quadrangular membrane is known as the vestibular ligament (false vocal fold)

Question 20

What is the attachment of the vocal and vestibular ligaments?

Answer 20

The vocal ligaments attach from the vocal processes of the arytenoid cartilage to the thyroid cartilage

The vestibular ligaments are superior and attach from the anterolateral surface of the arytenoid cartilages to the thyroid cartilage

Question 21

What is the opening between the true vocal cords and the arytenoid cartilages of the larynx known as?

What is the space between the true and false vocal folds known as?

Answer 21

The opening between the true vocal folds (vocal ligaments) and the arytenoid cartilage of the larynx is known as the rima glottidis

The space between the vocal ligament an vestibular ligament is known as the laryngeal ventricle

Question 22

What is the difference on the effect of sound production when comparing the vocal folds to the oral cavity (lips/cheeks/tongue)?

Answer 22

The vocal fold movements will change the air flow through the larynx to allow for phonation

• However its is the lips/cheeks/tongue that will allow for individual sounds/words to be created by their movements

Question 23

We will now discuss the muscles of the larynx - extrinsic and intrinsic muscles

• What are the extrinsic muscles of the larynx?
• Which help to elevate and which help to depress the larynx?
• What non-muscular structure also helps to depress the larynx?

Answer 23

Extrinsic musles of the larynx

• Elevation of larynx - suprahyoids (mylohyoid, geniohyoid, stylohyoid and digastric) as well as the stylopharyngeus
• Depression of larynx - infrahyoids (sternohyoid, thyrohyoid, sternothyroid, omohyoid) as well as the elastic recoil of the trachea

Question 24

How do the intrinsic muscles of the larynx function?

Answer 24

The intrinsic muscles of the larynx pass between elements of the larynx and move the cartilages or vocal folds

Question 25

Intrinsic muscles of the larynx

• * Cricothyroid
• * Thyroarytenoid
• * Posterior cricoarytenoid
• * Lateral cricoarytenoid
• * Oblique arytenoid
• * Transverse arytenoid

What is the nerve supply to all the intrinsic muscles of the larynx? Where do the nerves enter the larynx?

Answer 25

All the intrinsic muscles of the larynx are innervated by the recurrent laryngeal nerve which enters the larynx underneath the inferior constrictor of the pharynx EXCEPT the cricothyroid which is innervated by the external laryngeal branch of the superior laryngeal nerve

Question 26

What is the attachment of the cricothyroid muscle?

Answer 26

Cricothyroid has a straight and obique head

The cricothyroid attaches from the cricoid cartilage to the lamina (straight head) and inferior horn (oblique head) of the thyroid cartilage

Question 27

What is the function of the cricothyroid muscle? How does it bring about its function?

Answer 27

The cricothyroid will increase the distance between the thyroid cartilage and the arytenoid cartilages when it contracts as the thyroid becomes tilted forwards and the cricoid cartilage tilts backwards

Therefore it tenses and elongates the vocal folds

Question 28

What is the attachment of the thyroarytenoid muscles?

What are the medial fibres of this muscle which run alongside the vocal ligament known as?

Answer 28

Thyroarytenoid attaches from the inner surface of the angle of the thyroid cartilage to the anterolateral surface of the arytenoid cartilages

The medial fibres run alongside the vocal ligaments and are known as the vocalis muscles

Question 29

What is the function of the thyroarytenoid muscles? How does it bring about its function?

Answer 29

Thyroarytenoid muscles will pull the arytenoid cartilages closer to the thyroid cartilages

Therefore it shortens and relaxes the vocal ligaments

Question 30

What is the attachment of the posterior cricoarytenoid muscles?

Answer 30

They attach from the posterior aspect of the lamina of the cricoid cartilages to the muscular processes of the arytenoid cartilages

Question 31

What is the function of the posterior cricoarytenoid muscles? How does it bring about its function?

Answer 31

The posterior cricoarytenoid muscles will pull the muscular processes of the arytenoid cartilages backwards therefore rotating the vocal processes laterally

• Therefore it abducts the vocal folds

Question 32

What is the attachment of the lateral cricoarytenoid muscles?

Answer 32

Lateral cricoarytenoid muscles attach from the upper edge of the arch of the cricoid cartilage to the muscular processes of the arytenoid cartilages Can see in pic these are more anterior compared to posterior cricoarytenoid muscles

Question 33

What is the function of the lateral cricoarytenoid muscles? How does it bring about its function?

Answer 33

The lateral cricoarytenoid muscles will pull the muscular processes of the arytenoid cartilage forwards therefore rotating the vocal processes medially

Therefore it adducts the vocal folds

Question 34

What is the attachment and function of the oblique arytenoid muscles?

Answer 34

Attaches from the muscular processes of the arytenoid cartilages to the apex of the opposite arytenoid cartilage Some fibres will form aryepiglottic muscles in the aryepiglottic fold

Function - acts a sphincter to the laryngeal inlet

Question 35

What is the attachment function of the transverse arytenoid muscles?

Answer 35

Attaches from the posterior and medial aspect of the arytenoid cartilages to the opposite arytenoid cartilages

Function - closes the posterior aspect of the rima glottidis

Question 36

RESTATE the attachment and function of all the intrinsic muscles of the larynx No need to state how they bring about the function

Answer 36

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Question 37

What is the sensory and motor supply to the larynx?

Answer 37

Motor - Recurrent laryngeal nerve enters larynx underneath the inferior constrictor to supply all the intrinsic muscles except the cricothyroid supplied by the external laryngeal branch of the superior laryngeal nerve

Sensory - In ternal laryngeal branch of superior laryngeal nerve

Question 38

What is the arterial supply to the larynx?

Answer 38

Superior laryngeal branch of the superior thyroid artery - arises from anterior aspect of the ECA

Inferior laryngeal branch of the inferior thyroid artery - arises from the thyrocervical trunk from subclavian artery

Question 39

What is the venous drainage of the larynx?

Answer 39

Superior laryngeal vein via the superior thyroid vein into the internal jugular vein

Inferior laryngeal vein (both sides) drains into the left brachiocephalic vein via the inferior thyroid vein

Question 40

What is the lypmhatic drainage of the larynx?

Answer 40

Above the vocal cords - lymph drains to the superior deep cervical lymph nodes

Below the level of the vocal cords, lymph drains to the inferior deep cervical lymph nodes