Lecture 18 - Larynx Flashcards

1
Q

Functions of larynx

A

Airway protection - prevent aspiration of food
Ventilation
Cough reflex
Phonation

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2
Q

Larynx

A
Tube created by:
ligaments
muscles
cartilages
membrane 
hyoid 

Supraglottis
Glottis
Subglottis

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3
Q

Hyoid

A

Larynx is suspended from and lies below the hyoid

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4
Q

Borders of larynx

A

Begins at laryngeal inlet and ends at cricoid cartilage lower border

Continues as trachea

C4- C6

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5
Q

Laryngeal cartilage

A

Epiglottis
Thyroid cartilage
Cricoid cartilage - complete ring
Arytenoid cartilage

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6
Q

Laryngeal membranes

A

Thyrohyoid membrane

Cricothyroid membrane

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7
Q

Cricothroidotomy

A

Rare

When patients cannot be intubated or ventilated e.g. swelling of vocal cords

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8
Q

Vestibular fold

A

False vocal cords

Fold of vestibular ligament

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9
Q

Vocal fold

A

Fold of vocal ligament

True vocal cords

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10
Q

Lining of larynx

A

Respiratory mucous membrane = pseudostratified ciliated columnar epithelium with goblet cells

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11
Q

Supraglottis

A

Epiglottis to false vocal cords

Includes aryepiglottic fold

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12
Q

Glottis

A

Space between the flase and true vocal cords

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13
Q

Infraglottis (subglottis)

A

True vocal cords down

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14
Q

Saccule

A

Between vestibular and true vocal cords there is a small ventricle leads laterally and upwards into the saccule

Contains mucoius glands - keep true vocal glands moist

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15
Q

True vocal cord epithelium

A

Stratified squamous

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16
Q

Rima glottidus

A

Aperture between true vocal cords

17
Q

Intrinsic laryngeal muscles

A
  • Alter size and shape of laryngeal inlet

- Change position and tension of vocal cords

18
Q

Larynx when swallowing

A
  1. Hyoid bone elevated and moved anteriorly by suprahyoid muscles
  2. Larynx moves up and out
  3. Tongue pushes epiglottis posteriorly
  4. Aryepiglottis and thyroepiglottis muscles contract, narrowing laryngeal inlet as VC adduct and epiglottis moves more horizontally covering inlet.
  5. Food directed to piriform fossa
19
Q

Inspirations and expiration

A

Vocal cords abduct and inlet opens allowing movement of air

20
Q

Cricoarytenoid muscle

A

Only muscles to ABduct true vocal cords

moves arytenoid cartilage outwards

21
Q

Cricothyroid muscle

A

Lies externally

Origin: cricoid cartilage

Insertion: Thyroid cartilage

Action: Adduct true vocal cords by tilting thyroid cartilage on cricoid cartilage.
Produce high pitched sounds

Innervation: Only intrinsic muscle supplied by the external branch of the superior laryngeal nerve

22
Q

Cough

A
  1. Inspire and fill lungs with air using the external oblique muscles and diaphragm
  2. Vocal cords adduct
  3. Expiratory muscles contract - internal oblique and rectus abdominis
  4. Intrathoracic pressure increases
  5. Vocal cords suddenly abduct - cricoarytenoid muscles
  6. Explosive outflow of air
23
Q

High pitched sounds

A

VC are taught by cricothyroid muscle contraction bilaterally

24
Q

External branch of superior laryngeal nerve

A

Closely associated with superior thyroid artery

  • if there is a lesion - hoarse voice when attempting high pitched sounds
25
Q

Recurrent laryngeal nerve (CN X)

A

Sensory to subglottic
Motor to intrinsic muscles

LRLN - supplies left intrinsic muscles

26
Q

Internal superior laryngeal nerve

A

Sensory to supraglottic and glottis

27
Q

External superior laryngeal nerve

A

Motor to cricothyroid muscle

Accompanied by the arterial branches of the superior and inferior thyroid arteries - surgery may damage ESLN

28
Q

LRLN

A

Loops under aortic arch and longer so more easily damaged

Ascends into tracheo-oeophageal groove

Close anatomical relationship with thyroid gland and inferior thyroid arteries

May be damaged due to:

  • aortic aneurysm
  • oesophageal cancer
  • pancoast tumour
  • thyroid cancer
  • laryngitis
29
Q

RRLN

A

Loops under right subclavian artery

Ascends into tracheo-oeophageal groove

Close anatomical relationship with thyroid gland and inferior thyroid arteries

30
Q

Unilateral RLN lesion

A

Unilateral VC palsy

  • hoarse voice
  • ineffective cough
  • can be compensated for by contralateral VC

(damaged VC assumes paramedian position)

31
Q

Bilateral lesion of RLN

A

Both VCs paralysed in paramedian position

  • narrow glottis
  • significant airway obstruction
  • speech affected

Emergency surgery required - cricothyroidotomy

32
Q

Croup

A

Swelling around VC due to viral infection

Presents in babies:

  • barking cough that sounds like a seal
  • hoarse voice
  • difficulty breathing
  • rasping sound when breathing in