Larynx Flashcards

1
Q

Over what vertebrae does the larynx relate?

What level are the thyroid and cricoid cartilages?

A

Posteriorly related to C3-C6 vertebral bodies
Thyroid - C4-C5
Cricoid - C6

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2
Q

What is the vestibule of the larynx?

A

The cavity superior to the vestibular folds up to the level of the epiglottis

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3
Q

What is the ventricle of the larynx?

A

The smallest cavity that extends laterally between the vestibular folds and the vocal folds

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4
Q

What is the infraglottic cavity of the larynx?

A

Cavity extending from vocal folds to inferior border of the cricoid cartilage. (Under that is the trachea)

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5
Q

What is the function of the thyroid + cricoid + arytenoids cartilages?

A

Change position and tension of the vocal folds to produce variations in voice pitch

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6
Q

What is the function of the epiglottic + 2 cuneiform + 2 corniculate caritlages?

A

Keep food + foreign bodies out of the larynx

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7
Q

How many laryngeal cartilages are there?

A

9: three paired, three unpaired
Unpaired: thyroid, cricoid, epiglottis
Paired: arytenoid, corniculate, cuneiform

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8
Q

What fuses to form the laryngeal prominence and what does it make?

A

The two thyroid lamina fuse anteriorly to make a single thyroid cartilage.

The angle of fusion is sharper in males = more prominent Adam’s apple

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9
Q

What is located posteriorly on the thyroid cartilage? What is their attachment?

A

Superior horns - attach to lateral thyroid ligaments / all around lamina to thyrohyoid membrane
Inferior horns - attach to cricoid on medial surface of horn

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10
Q

What muscles attach laterally on the thyroid cartilage?

A

Sternothyroid, thyrohyoid, inferior pharyngeal constrictor

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11
Q

What is the cricothyroid joint and what is its function?

A

It as the attachment of the cricoid cartilage via its lateral facets to the inferior horn of each thyroid lamina. Functions to allow thyroid cartilage to tilt on cricoid - thyroid cartilage rocks back and forth

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12
Q

What is the cricothyroid ligament?

A

Ligament attaching the two cartilages via inferior part of thyroid cartilage

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13
Q

What is the shape of the cricoid cartilage and what are its facets?

A

Singlet ring with thick part direct posteriorly. Has lateral facets for articular with inferior horn of thyroid cartilage, and superior facets for articulation with arytenoids. There is a definitive ridge posteriorly

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14
Q

Where do the arytenoid cartilages sit and what defines their three corners?

A

They are 3-sided pyramidal cartilages which sit atop the cricoid cartilage and are relatively smooth medially, and pitted laterally.

Apex - oriented superiorly and attaches to aryepiglottic fold, holds corniculate cartilage
Muscular process
Vocal process

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15
Q

What is the muscular process of the arytenoid cartilages?

A

Side attached to intrinsic laryngeal muscles, normally pointed posteriorly.

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16
Q

What is the vocal process of the arytenoid cartilages?

A

Side attached to the vocal ligaments, normally pointed anteriorly

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17
Q

What are the corniculate & cuneiform cartilages?

A

They are paired cartilages in the posterior region of the aryepiglotic folds, with the corniculate being directly atop the arytenoids and the cuneiform being slightly above it.

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18
Q

What is the purpose of the corniculate / cuneiform cartilages?

A

They help prevent food and foreign bodies from entering the larynx by stabilizing the structural integrity of the aryepiglotic folds whenever they are closed (so trachea can remain closed off)

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19
Q

What is the epiglottic cartilage and its function?

A

A single thin cartilage shaped like a leaf. Closes the laryngeal inlet (aditus) during swallowing

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20
Q

What are the two ligament attachments of the epiglottic cartilage?

A
  1. Thyroepiglottic ligament - inferior attachment, to inside of laryngeal prominence
  2. Hyoepiglottic ligament - anterior surface attaches upward to the hyoid bone (helps lift larynx during swallowing)
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21
Q

Where do the vocal ligaments extend?

A

Vocal process of arytenoids to the inside of laryngeal prominence (just below attachment of thyroepiglottic ligament)

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22
Q

What two ligaments extend from cricoid cartilage to vocal ligaments?

A

Median and lateral cricothyroid ligaments. Median is partially found behind laryngeal prominence

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23
Q

What is the conus elasticus?

A

The two cricothyroid ligaments + the vocal ligaments

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24
Q

What does vocal folds refer to?

A

The conus elasticus covered by mucosa - true vocal cords

Two cricothyroid ligaments + vocal ligaments

25
Q

What is the rima glottidis?

A

The space between the vocal folds

26
Q

What is the glottis?

A

Refers to the larynx at the level of the vocal folds

27
Q

What are the vestibular folds?

A

They are the false vocal cords. They are the bottom lip of the quadrangular membrane which extend from thyroid to arytenoid cartilages. Above the true vocal cords

28
Q

What is the vestibular ligament?

A

Fibrous ligament above the vocal ligaments extending from depression on arytenoids to the thyroid cartilage.

29
Q

What forms the aryepiglottic fold?

A

The superior edge of the quandrangular membrane which engulfs the cuneiform and corniculate cartilages. Extends between epiglottis and arytenoid cartilages.

30
Q

What is the quadrangular membrane?

A

Membrane that extends from vocal ligaments to epiglottis, forms the aryepiglottic / vestibular folds

31
Q

What is the space surrounded by the quadrangular membrane called?

A

The vestibule

32
Q

What is the function of the vestibular folds?

A

Helps to close the larynx during swallowing and also during effort closure

33
Q

What is the space between the vestibular folds called?

A

rima vestibuli

34
Q

What are the three muscles of the laryngeal inlet? What is their general function? What innervates them?

A
  1. Transverse arytenoid muscle
  2. Oblique arytenoid muscle
  3. Thyroepiglottic muscle
  • Function to approximate the aryepiglottic folds (bring together) and move arytenoids towards epiglottis as it closes. They close the laryngeal inlet

Innervation: Recurrent laryngeal nerve (X)

35
Q

What is the transverse arytenoid muscle?

A

Unpaired muscle which pulls across the arytenoids horizontally on posterior side to bring them together, thus closing the vocal + vestibular ligaments

36
Q

What is the oblique arytenoid muscle? What does it continue as?

A

Paired muscle making X superfically to transverse arytenoid. Continues as aryepiglottic muscle to pull the epiglottic folds and arytenoids towards midline

37
Q

What is the thyroepiglottic muscle?

A

The continuation of the thyroarytenoid muscle (basically the superior fibers of it). Changes the size of the laryngeal inlet and keeps it tense, helping the epiglottis shut over the inlet as the larynx moves up during swallowing.

38
Q

What is the thyroarytenoid muscle?

A

The muscle extending from arytenoids to the thyroid cartilage for closing the larynx. It is continued and part of the THYROEPIGLOTTIC muscle

39
Q

What does the lateral cricoarytenoid muscle do?

A

Vocal muscle which CLOSES the rima glottidis by pulling muscular processes of arytenoid (on posterior) anteriorly towards the lateral attachment on cricoid cartilage

40
Q

What does the posterior cricoarytenoid muscle do?

A

Vocal muscle which OPENS the rima glottidis by pulling muscular processes of arytenoid (on posterior side) medially towards the posterior attachment on cricoid cartilage

41
Q

What does bilateral paralysis of posterior cricoarytenoid muscle do?

A

Narrows the rima glottidis, leading to suffocation

42
Q

What are the cricothyroid muscles + their function + innervation?

A

Paired muscles arising from anterolateral surface of cricoid attaching to inferior horn of thyroid cartilage.

Function: Tensor: pulls thyroid cartilage to rock anteriorly, elongating / tightening vocal ligaments. Raises vocal ligaments

Innervation: External laryngeal nerve (X, branch of superior laryngeal)

43
Q

What are the thyroarytenoid muscles?

A

Paired muscles that are continued as the thyroepiglottic muscle. They arise form thyroid cartilage and insert on arytenoid cartilage

Function: Relaxes vocal cords by bringing arytenoids anteriorly, slackening them. Lowers voice pitch

44
Q

What causes monotonous voice?

A

Damage to external laryngeal nerve - unable to raise voice pitch due to damage to cricothyroid

45
Q

What is the vocalis muscle?

A

An extension of the thyroarytenoid muscle, attaching to the vocal ligament. Contraction can make small adjustments in voice pitch

46
Q

What is the blood supply to the larynx?

A

Superior laryngeal artery (branch of superior thyroid, from external carotid)

Inferior laryngeal artery (branch of inferior thyroid artery, off of thyrocervical trunk, 1st part of subclavian)

47
Q

What are the two branches of the superior laryngeal nerve (from CNX)?

A

Internal laryngeal artery - sensory only (above and at vocal cords). Relates to superior laryngeal a.
External laryngeal artery - motor only (to cricothyroid only)

48
Q

What nerve gives sensory innervation of larynx at or below vocal cord level (infraglottic region)?

A

Recurrent laryngeal nerve

49
Q

What is the motor innervation to all muscles of the larynx except cricothyroid?

A

Recurrent laryngeal nerve (CN X)

50
Q

What is the course of the recurrent laryngeal nerve?

A

Wraps around subclavian artery (right) or aortic arch (left) before passing between trachea and esophagus while thyroid is medial. It relates closely to the inferior laryngeal artery near its entrance to the larynx.

51
Q

How do the vocal cords appear clinically, and what can be used to view them?

A

They appear whiter than the vestibular folds. Laryngoscopic mirror or laryngoscope can be used.

52
Q

When might you want to visualize the vocal folds and rima glottidis?

A

To see the extent of the damage to the larynx resulting from trauma, tumor growth, or damage to recurrent laryngeal nerve during thyroidectomy.

53
Q

How big is the rima glottidis during phonation?

A

Almost completely closed, very small letting air through. Normal respiration is much bigger (not to mention forced inspiration). It is near total adduction of vocal ligaments

54
Q

What is laryngeal spasm vs laryngeal obstruction?

A

Spasm - coughing due to touch sensitivity of laryngeal aditus
Obstruction - This is real choking, something blocking the airway. Occurs as a result of object lodged in rima glottidis.

55
Q

What is a common cause of choking?

A

Alcohol consumption reducing sensitivity of laryngeal aditus, letting food get lodged in rima glottidis. Little sound will be made because the person can’t get air

56
Q

What is an emergency cricothyrotomy?

A

Stick a tube like an empty pen through the median cricothyroid ligament to provide an air passage, without any anesthesia or surgical instruments. Do after the Heimlich fails

57
Q

What is tracheotomy vs tracheostomy?

A

Otomy - slit incision in trachea

Ostomy - Round or square hole in trachea

58
Q

Where is a tracheostomy or tracheostomy normally done? What needs to be done?

A

Between 2nd and 3rd tracheal rings, isthmus of thyroid must be moved by division or superior reflection. A plexus of inferior thriod veins may be present, and sometimes thyroid ima artery, complicating things.

59
Q

Why is it riskier to do a tracheotomy in children?

A

The thymus gland covers the inferior part of trachea, and it is more mobile, so you are at higher risk of cutting the esophagus.