Lec 11

Question 1

What is the function of larynx

Answer 1

Compound sphincter closing airway during swallowing and vaksalva maneuver (coughing/ heavy lifting). Fx accomplished by larynx and accompanying structures.

Question 2

What are the accompanying structures of the larynx

Answer 2

1. Hyoid bone - at C3, 10 infra and suprahyoid muscles move hyoid bone and larynx
2. Larynx - 6 cm long, up bord at C34, low bord at C6
3. Immediately below larynx is thyroid gland

Question 3

What are the components of larynx structure

Answer 3

1. Hyoid bone
2. Thryohyoid membrane
3. Thyroid catilage
4. Cricoid catilage

Question 4

Describe the hyoid

Answer 4

paired lesser cornua (horns) laterally and greater posteriorly. Stylohyoid ligament runs btwn styloid process and lesser horn. Muscles attached along outer surface of greater horn and body

Question 5

Describe the Thyrohyoid membrane

Answer 5

connects hyoid bone to thyroid cartilage, pierced supero-lat by sup laryngeal artery and nerve

Question 6

Describe the Thyroid cartilage

Answer 6

Comprised of two lamina fused anterior midline, upper border has median thyroid notch, below notch is laryngeal prominence.
Smooth outer surface ends posteriorly on either side at oblique line btwn sup and inf tubercles to which the sternothyroid muscle inserts.
Posterolateral borders thicken for insertion of stylopharngeus and palatopharyngeus muscles.
Ends are drawn out to a pair of sup and inf cornua which articulates with lamina of cricoid and allows hing action.

Question 7

Describe the cricoid cartilage

Answer 7

Attached to thyroid cartilage by cricothyroid membrane which is below vocal cords and can be pierced (cricothryotomy) to give emergency air passage.
Signet ring shape, broad post narrow ant, lamina has median ridge for longitudinal fibrous tendons of esophagus

Question 8

Describe the arytenoid cartilage

Answer 8

Pyramide shapes on upper post lateral borders of cricoid with additional corniculate cartilage at the apex. Joints with cricoid allow sliding to and fro, tilt, and rotation of the vocal cords

Question 9

Where are the movements of the larynx done

Answer 9

cricoarytenoid and cricothyroid joints

Question 10

Path of the vocal ligaments

Answer 10

From vocal process of arytenoid to junction of thyroid cartilage.

Question 11

Path of the vestibular ligaments

Answer 11

ant surface of arytenoid to base of epiglottis

Question 12

Regulation of vocal cord tension

Answer 12

Primarily by pivoting thyroid cartilage foreward or back. Higher tension = higher pitch. Movement by cricothyroid muscle.

Question 13

Describe the cricothyroid muscle

Answer 13

Runs btwn the external surface of thyroid and cricoid arches. N - external branch of the superior laryngeal nerve of vagus. Paralysis = monotone

Question 14

Describe the Thyroarytenoid muscle

Answer 14

Opposes action of cricothyroid muscle. Has two bellies:

1. externus - ant thyroid cartilage to lateral arytenoid and acts to shorten and adduct vocal processes
2. Internus: ant thyroid cart to vocal processes of arytenoid and acts to shorten and tense vocal process therefore reducing pitch

Question 15

Describe the posterior-cricoarytenoid muscle

Answer 15

Post cricoid lamina to muscular process of arytenoid. Moves vocal processes up and lateral performing abduction and opening of rima glottis

Question 16

Describe the Lateral cricoarytenoid muscle

Answer 16

Paired, ant muscular process of arytenoid to sup border of cricoid. Acts to adduct and increase length of vocal folds and movement parallel to thyroarytenoid

Question 17

Describe the Interarytenoid muscle

Answer 17

Transverse and oblique fibers. Transverse runs between medial surface of arytenoid, oblique runs to epiglottis as ary-epiglotticus muscle. Action is to adduct and narrow rima glottis. Can be opposed so vocal cords slightly abducted resulting in whisper

Question 18

Describe the vestibular fold

Answer 18

Created by fibroelastic quadrangular membrane between arytenoid and epiglottis. Known as false vocal cords.

Question 19

Describe the vocal fold

Answer 19

Vocal ligament and vocalis muscle covered by mucosa. Vibrates during speech. Each one fills hal of rima glottis.

Question 20

Relationships of larynx

Answer 20

Inferior to vestibular fold is fusiform laryngeal sinus

Question 21

Describe Phonation

Answer 21

Speech is the forced air movement between closely opposed vocal cords causing vibrations in vocal folds. Tense cricothyroid action results in strong vibrations and increased pitch. Relaxation and shorter cords via vocalis results in decreased pitch.
Resonance aided by pharynx, oral region, and nasal passage while voice modified by action tongue, lips, palatine musculature

Question 22

What are the muscles regulating laryngeal sphincter

Answer 22

Contraction of lateral cricoarytenoid, transverse and oblique arytenoid, ary-epiglottic brings vocal folds together and pulls arytenoid cartilage towards epiglottis preventing food from entering trachea.

Question 23

Describe the vasculature and innervation of larynx

Answer 23

1. Internal laryngeal nerve - sense and autonomic superior to vocal cords and is accompanied by superior laryngeal artery.
2. External laryngeal nerve (branch of sup laryngeal) provides motor to cricothyroid and travels with superior thyroid artery which is endangered during surgery
3. Inferior laryngeal nerve supplies muscles of larynx and sensation below vocal cords. It is a terminal branch of recurrant laryngeal nerve and travels with inferior laryngeal artery and passes behind thyroid gland which puts it at risk.

Question 24

Innervation by Vagus information

Answer 24

M: LMNs in nuc ambiguous to all musculature of larynx and stylopharyngeus
Aff: 2 ganglion
1. Superior jugular ganglion - 1st order sensation
2. Inf nodose ganglion - 1st order nonconscious information to solitary nucleus in brainstem

Question 25

Common pathoologies

Answer 25

1. Nodules - growth by overuse may need surg
2. Polyps - benign lesions causing hoarse and breathy voice that tires easily - may need surg
3. Laryngitis (sicca) - dehydration thick mucous so vibration is incorrect