L19: Larynx

Question 1

What are the cartilages of the larynx? Which are single, which are paired?

Answer 1

• Thyroid: single - Cricoid: single - Epiglottic: single - Arytenoid: paired - Corniculate: paired - Cuneiform: paired

Question 2

Structures of thyroid cartilage

Answer 2

• Laryngeal prominence: two quadrilateral laminae open posteriorly and fuse anteriorly to form this - Thyroid notch: V-shaped structure formed by superior laryngeal prominence - Superior and inferior horns: are posterior border projections

Question 3

What is the posterior part of the cricoid cartilage called? Anterior part?

Answer 3

• Posterior part = lamina – arytenoid cartilage sits on top of this - Anterior part = arch

Question 4

What is the structure that connects the inferior end of the epiglottic cartilage to the thyroid cartilage?

Answer 4

• Thyroepiglottic ligament

Question 5

Describe the arytenoid cartilage

Answer 5

• Pyramidal cartilage with anterior processes known as vocal processes - Lateral processes known as muscular processes - Apex = superior portion - Base = inferior portion

Question 6

What are the two cartilages found in the aryepiglottic fold? What is the function?

Answer 6

• Corniculate (sits on apex of arytenoid cartilage) - Cuneiform - They both support the aryepiglottic fold

Question 7

Joints of larynx

Answer 7

• Cricothyroid: synovial joint bw inferior horn of thyroid and lateral surface of cricoid cartilage - Cricoarytenoid: synovial joint bw base of arytenoid cartilage and superior lamina of cricoid cartilage

Question 8

What movement occurs at cricothyroid joint?

Answer 8

• Rotation and gliding between thyroid and cricoid cartilage

Question 9

What movement occurs at the cricoarytenoid joint?

Answer 9

• Sliding, tilting anterior and posterior, rotatory

Question 10

This ligaments suspends the larynx

Answer 10

• Thyrohyoid membrane

Question 11

What structures pierce the thyrohyoid membrane?

Answer 11

• Internal laryngeal nerve (from vagus) and superior laryngeal artery (from superior thyroid of external carotid)

Question 12

What is the ligament connecting the cricoid cartilage to the thyroid cartilage?

Answer 12

• Cricothyroid ligament

Question 13

How is an emergency cricothyroidectomy performed?

Answer 13

• Find the thyroid notch - Move inferiorly to find the cricothyroid ligament (superior to cricoid cartilage) - Save a life

Question 14

What is the ligament connecting the cricoid cartilage to the first tracheal ring?

Answer 14

• Cricotracheal ligament

Question 15

What are ligaments beneath the first tracheal ring called?

Answer 15

• Tracheal ligaments

Question 16

What are the ligaments found in the “lumen” of the larynx?

Answer 16

• Vocal ligament/fold – extends from junction of laminae of thyroid cartilage (ant) to the vocal processes of arytenoid cartilage (post). These are true vocal cords - Vestibular ligament/fold – free edges of quadrangular membrane. These are false vocal cords

Question 17

What is the quadrangular membrane?

Answer 17

• Thin submucosal sheet of CT extending from arytenoid cartilage to epiglottic cartilage and covered by aryepiglottic fold. Free edges of this membrane create the vestibular ligament / fold, which are the false vocal cords

Question 18

What is the conus elasticus?

Answer 18

• Elastic membrane extending from cricoid cartilage of the vocal ligament, which consists of median cricothyroid ligament, vocal ligament and cricothyroid ligament

Question 19

3 Compartment of larynx

Answer 19

• Vestibule (superior to vestibular folds) - Ventricle (cavity on the lateral walls bw vestibular and vocal folds) - Infraglottic cavity (bw vocal folds and inferior border of the cricoid cartilage)

Question 20

What is the opening between the vocal folds known as?

Answer 20

• Rima glottidis

Question 21

What is the glottis?

Answer 21

• Vocal folds, rima glottidis and narrow part of larynx as level of vocal folds. Think about drawing a horizontal line through vocal folds.

Question 22

What is the opening between the vestibular folds known as?

Answer 22

• Rima vestibuli

Question 23

What occurs at the rima vestibuli?

Answer 23

• Closes during swallowing to prevent food from entering larynx

Question 24

Muscles of larynx. Function?

Answer 24

• Infrahyoid muscles: depress hyoid bone and therefore larynx, creating low pitch voices - Suprahyoid muscles: elevate hyoid bone and therefore larynx, creating high pitch voices - Transverse arytenoid (only unpaired): close laryngeal outlet, reinforce adducting vocal cords - Oblique arytenoid: close laryngeal outlet - Lateral cricoarytenoid: adduct vocal cords - Posterior cricoarytenoid: abduct vocal cords - Cricothyroid: tense vocal cords - Thyroarytenoid: relax vocal cords - Vocalis - Thyroepiglottus: widens laryngeal inlet

Question 25

What muscles close the laryngeal inlet?

Answer 25

- Transverse arytenoid (unpaired) - Oblique arytenoid

Question 26

What muscles widen the laryngeal inlet?

Answer 26

- Thyroepiglottus

Question 27

What muscles adduct the vocal cords?

Answer 27

- Lateral cricothyroid (reinforced by transverse artenoid)

Question 28

What muscles abduct the vocal cords?

Answer 28

- Posterior cricoarytenoid

Question 29

What muscles cause low pitch voices?

Answer 29

- Infrahyoid muscles

Question 30

What muscles cause high pitch voices?

Answer 30

- Suprahyoird muscles

Question 31

What muscles tense the vocal cords?

Answer 31

- Cricothyroid

Question 32

What muscles relax the vocal cords?

Answer 32

- Thyroarytenoid

Question 33

Blood supply to larynx

Answer 33

- Superior and inferior laryngeal artery (branches from superior and inferior thyroid arteries, which originate from external carotid and thyrocervical trunks (off subclavian) respectively)

Question 34

Innervation of larynx. Describe branches and what they innervate

Answer 34

- Vagus – CNX 1. )Superior laryngeal nerve branches into internal laryngeal and external laryngeal a. )Internal laryngeal (sensory only) supplies mucous membranes superior to vocal folds b. )External laryngeal (motor only) innervates cricothyroid muscle 2. )Recurrent laryngeal nerve (sensory and motor) loops under subclavian on right and aortic arch on left - Innervates all intrinsic laryngeal muscles (so, no cricothyroid innervation) - Innervates mucous membranes inferior to vocal folds

Question 35

What are the branches of the superior laryngeal nerve? Motor, sensory or both?

Answer 35

- Internal laryngeal: sensory - External laryngeal: motor

Question 36

Is recurrent laryngeal nerve motor or sensory?

Answer 36

- Both

Question 37

What nerve supplies the intrinsic muscles of the larynx?

Answer 37

- Recurrent laryngeal nerve innervates all intrinsic laryngeal muscles, with exception of cricothyroid - Cricothyroid muscle is supplied by external laryngeal

Question 38

Describe difference between larynx between males and females/children?

Answer 38

- Shorter in women and children, slightly more superior - Men have longer, ant to vertebral bodies C3-6

Question 39

What nerve innervates mucous membrane of larynx?

Answer 39

- Mucous membranes superior to vocal folds innervated by internal laryngeal nerve - Mucous membranes inferior to vocal folds innervated by recurrent laryngeal nerve