AH&N- Larynx

Question 1

What are the three sections of the internal cavity of the larynx?

Answer 1

Supraglottis: inferior surface of the epiglottis to vestibular folds
Glottis: contains vocal cords 1cm below them, opening between the vocal cords is the rima glottidis, the size of which is altered by phonation.
Subglottis: inferior border of the glottis to the inferior border of the cricoid cartilage.

Question 2

Describe the structure of the larynx.

Answer 2

Formed by a cartilaginous skeleton held together by ligaments and membranes.
The laryngeal muscles act to move the components of the larynx for phonation and breathing.
Internal cavity
The internal surface of the larynx is lined by a mucous membrane with ciliated columnar epithelium

Question 3

Describe the anatomical location of the larynx.

Answer 3

️anterior compartment of neck, suspended from the hyoid bone and spanning between C3 & C6.
It is continuous inferiorly with the trachea & opens superiorly into the laryngeal part of the pharynx.
Covered anteriorly by the infra hyoid muscles and laterally by the loves of the thyroid gland.

Question 4

Describe the path of the laryngeal arteries.

Answer 4

Superior laryngeal artery: branch of the superior thyroid artery (derived from the external carotid). It follows the internal branch of the superior laryngeal nerve into the larynx.
Inferior laryngeal artery: branch of the inferior thyroid artery (derived from the thyrocervical trunk). It follows the recurrent laryngeal nerve into the larynx.

Question 5

Describe the venous drainage of the larynx.

Answer 5

Superior laryngeal vein: drains into the internal jugular vein via the superior thyroid.
Inferior laryngeal vein: drains into the brachiocephalic vein via the inferior vein.

Question 6

Describe the innervation of the larynx.

Answer 6

Vagus nerve: both motor and sensory innervation
Recurrent laryngeal nerve: sensory innervation to the infraglottis & motor innervation to all the internal muscles of larynx (except cricothyroid)
Superior laryngeal nerve: internal branch provides sensory innervation to the supraglottis & the external branch provides motor innervation to the cricothyroid.

Question 7

How can damage to the larynx be caused?

Answer 7

Apical lung cancer, thyroid cancer, aortic aneurysm, cervical lymphadenopathy or damaged iatrogenic ally during neck surgery.

Question 8

What is unilateral palsy of the recurrent laryngeal nerve?

Answer 8

One vocal cord paralysed, other tends to compensate and speech is not affected to a certain degree, although may have hoarseness.

Question 9

What is bilateral palsy of the recurrent laryngeal nerves?

Answer 9

Both vocal cords paralysed in a position between adduction and abduction, breathing impaired and phonation cannot occur.

Question 10

What happens when the recurrent laryngeal nerves are only partially damaged?

Answer 10

Vocal cords paralysed in fully addicted position.
If this occurs bilaterally the rima glottidis is completely closed & emergency surgical intervention is required to restore the airway.

Question 11

What are the extrinsic muscles of the larynx and what are their functions?

Answer 11

The suprahyoid muscles and the stylopharyngeus elevates the larynx whilst the infra hyoid muscles depress the larynx.

Question 12

What are the attachments, actions and innervation of the cricothyroid muscle?

Answer 12

Attachments: originates from the anterolateral aspect of the cricoid cartilage & attaches to the inferior margin & inferior horn of the thyroid cartilage.
Actions: stretches & tenses the vocal ligament
Innervation: external laryngeal nerve

Question 13

What are the attachments, actions and innervation of the thyroarytenoid muscle?

Answer 13

Attachments: originates from the inferoposterior aspect of the angle of the thyroid cartilage & attaches to the anterolateral part of the arytenoid cartilage.
Actions: relaxes the vocal ligament
Innervation: inferior laryngeal nerve

Question 14

What are the attachments, actions and innervation of the posterior cricoarytenoid?

Answer 14

Attachments: originates from the posterior surface of the cricoid cartilage & attaches to the muscular process of the arytenoid cartilage.
Actions: abducts vocal folds & therefore widens rima glottidis
Innervation: inferior laryngeal nerve

Question 15

What are the attachments, actions and innervation of the transverse & oblique arytenoids?

Answer 15

Attachments: spans from one arytenoid cartilage to the opposite arytenoid
Actions: Adducts the arytenoid cartilages therefore closing the posterior portion of rima glottidis, narrows laryngeal inlet
Innervation: inferior laryngeal nerve

Question 16

How many cartilages are located in the larynx?

Answer 16

3 unpaired and 6 paired

Question 17

Name the three unpaired cartilages of the larynx.

Answer 17

Thyroid cartilage
Cricoid cartilage
Epiglottis

Question 18

Describe the thyroid cartilage.

Answer 18

large prominent structure in males. 2 laminae which join together anteriorly to form the laryngeal prominence. Posterior border of each sheet project superiorly & inferiorly to form the superior & inferior horns. Superior horns articulate with the hyoid bone, inferior with cricoid cartilage.

Question 19

Describe the cricoid cartilage.

Answer 19

Complete ring of hyaline cartilage, broad sheet posteriorly & a narrower arch anteriorly.
Completely encircles the airway making the inferior border of the larynx at C6.
Articulates with paired arytenoid cartilages posteriorly & providing an attachment for the inferior horns of the thyroid cartilage.

Question 20

Describe the epiglottis.

Answer 20

Leaf shaped plate of elastic cartilage, marks the entrance to the larynx.
It’s stalk is attached posteriorly to the thyroid cartilage.
During swallowing it moves towards the arytenoid cartilages to close off the larynx and prevent aspiration.

Question 21

Name the six paired laryngeal cartilages.

Answer 21

Arytenoid cartilages
Corniculate cartilages
Cuneiform cartilages

Question 22

Describe the arytenoid cartilages.

Answer 22

Pyramidal shaped structures that sit on the cricoid cartilage- apex, base, 3 sides and 2 processes.
Apex-articulates with corniculate cartilage
Base-articulates with the superior border of the cricoid cartilage
Vocal process-provides attachment for the vocal ligament
Muscular process-provides attachment for the posterior & lateral cricoarytenoid muscles

Question 23

Describe the corniculate cartilages.

Answer 23

Minor cartilaginous structures& articulate with the apices of the arytenoid cartilages.

Question 24

Describe the cuneiform cartilages.

Answer 24

Located in the ary-epiglottic folds- no direct attachments but act to strengthen the folds.

Question 25

What are the functions of the larynx?

Answer 25

Phonation, cough reflex and protection of the lower respiratory tract.