Larynx

Question 1

What are the main functions of the larynx?

Answer 1

• Prevents passage of food or drink into airway during swallowing.
• Regulates flow of air to and from the lungs during vocalization.

Question 2

What is the function of the epiglottis? How is it tethered to the tongue?

Answer 2

The epiglottis prevents food and liquid from going down into the trachea. The epiglottis is not really directly attached to the tongue, but there is a continuous mucosa
that connects to both the tongue and the epiglottis.

Question 3

What is the clinical relevance of the median cricothryoid ligament?

Answer 3

This ligament along with the membrane are perforated in order to create an emergency airway and is easier to perform than a tracheotomy. This is more commonly used in situations that are not in a clinic.

Question 4

Describe the anatomical position of the vestibular vs the true vocal folds?

Answer 4

The vestibular folds are directly superior to the vocal folds.

Question 5

Where is the laryngeal vestibule and what innervates its mucosa?

Answer 5

The internal branch of the superior laryngeal nerve innervates the mucosa of the laryngeal vestibule which is above the vocal folds.

Question 6

What innervates the mucosa of the infraglottic cavity?

Answer 6

The inferior laryngeal nerve, which is a branch of the recurrent laryngeal nerve innervates the mucosa below the vocal folds including the infraglottic cavity.

Question 7

What muscle/s abduct and adduct the vocal folds?

Answer 7

Abduct:
-Posterior Cricoarytenoid

Adductors:

• Lateral Cricoarytenoid
• Transverse arytenoid
• Oblique arytenoid
• Aryepiglottic
• Thyroarytenoid
• Thyroepiglottic

Question 8

How would a unilateral lesion of the recurrent laryngeal nerve present clinically? A bilateral
lesion?

Answer 8

Unilateral damage would result in hoarseness, while bilateral damage would result in breathlessness due to the loss of positive pressure in the lungs.

Question 9

Describe the blood supply to the upper and lower larynx. What do each of these vessels branch
from?

Answer 9

Most blood to the larynx is via the superior laryngeal a. a branch of superior thyroid artery from external carotid. Some of the lower thyroid is provided by the inferior laryngeal artery which is a branch of the inferior thyroid artery ( a branch off of the thyrocervical trunk.)

Question 10

What is a tracheostomy? What vein and artery must be avoided? In children, what other organ
must be considered and avoided?

Answer 10

A tracheostomy establishes an airway in patients with an upper airway obstruction or respiratory failure. The inferior thryroid veins and the thyroid ima artery must be avoided. In children, the thymus must be avoided as well.

Question 11

Describe the cartilaginous anatomy of the larynx, including paired and unpaired cartilages.

Answer 11

Laryngeal skeleton formed by 3 paired (moveable) and 3 unpaired (immovable cartilages). Unpaired:
-Thyroid: two flat laminae joined by laryngeal prominence (Adam’s apple). Has sup/inf horns and oblique line on lateral face
-Cricoid: only complete ring in airway! Narrow arch anteriorly and high lamina posteriorly. Is end of larynx and beginning of trachea
-Epiglottis: spoon-shaped plate behind root of tongue, attached at lower end to back of Thyroid cartilage
Paired:
-Arytenoids: pyramid-shaped. Bases articulate with cricoid. Have anterior vocal processes and posterolateral muscular processes
-Corniculates: on top of arytenoid and enclosed within aryepiglottic folds
-Cuneiforms: enclosed in aryepiglottic folds anterior to corniculates

Question 12

What mucosal folds bound the laryngeal inlet?

Answer 12

The laryngeal inlet is bounded on each side by the ary-epiglottic folds that cover the ary-epiglottic ligament and contain the superior end of the cuneiform cartilage

Question 13

What is the glottis?

Answer 13

The glottis is the vocal apparatus of the larynx. The glottis + the rima glotidis makes up the vocal folds and processes. (rima glotidis = aperture between vocal folds and arytenoid cartilages)

Question 14

What innervates the mucosa over the vestibular folds and the ventricle?

Answer 14

The internal laryngeal nerve (a branch of the superior laryngeal nerve) supplies sensory innervation to all mucous membranes above the vocal folds, which includes the ventricle and vestibular folds.

Question 15

What muscles adjust tension on the vocal folds and what impact does this have on pitch?

Answer 15

(2) tensor mm of the larynx:
- Cricothyroid m: principle tensor that pulls thyroid cartilage anteriorly, which elongates and tightens the vocal ligaments and raises pitch
- Vocalis m: a weak adductor of the vocal cords, that selectively tenses (raises pitch) and relaxes (lowers) parts of the vocal folds to modulate pitch

Question 16

What 2 branches of the vagus nerve innervate the larynx? Describe their branching pattern, noting which are motor/sensory/mixed nerves. What does each innervate within the larynx?

Answer 16

The 2 nerves of the larynx are the Superior and Inferior laryngeal branches of the vagus nerves.

• The superior laryngeal n arises from the inferior vagal ganglion in the carotid triangle. It divides into 2 terminal branches within the carotid sheath: the internal laryngeal n. (sensory above vocal cords AND autonomic) and the external laryngeal n (motor to Cricothyroid m and Inf pharygeal constrictor mm)
• The inferior laryngeal n is a continuation of the recurrent laryngeal n. It is both motor and sensory, supplying all intrinsic mm except cricothyroid and sensory inn below vocal cords

Question 17

How would a lesion of the superior laryngeal nerve present clinically?

Answer 17

Foreign bodies will be able to easily enter the larynx. Paralysis of the superior laryngeal nerve causes anesthesia of the superior laryngeal mucosa, thus inactivating the protective mechanism that keeps foreign bodies out of the larynx.
Injury to the external branch (of sup laryng n) results in monotonous voice due to paralyzed cricothyroid muscle being unable to vary length/tension of vocal fold

Question 18

What happens when a foreign object is aspirated into the laryngeal vestibule? What procedure can be used to dislodge the object from the larynx?

Answer 18

A foreign object aspirated through the laryngeal inlet will become trapped in the vestibule of the larynx. This causes the rima glottidis to close and blockage of air to the trachea with resulting asphyxiation. The blockage can be released by the Heimlich maneuver, which causes a rapid burst of air through the larynx dislodging the obstruction.