Larynx anatomy

Question 1

What is the function of the larynx based on its position?

Answer 1

Fully open/abducted = ventilation
Fully closed /adducted = sphincter
Half open = phonation/voice production

Question 2

Label what can be seen down the laryngoscopy

Answer 2

tongue
Epiglottis
Aryepiglottic fold
Cuneiform tubercle
Corniculate tubercle
Rima glottis
Vocal cord
Vestibular fold.
Laryngeal inlet
Vestibule
Piriform recess
Laryngopharynx (closed)

Question 3

What is the basic process of swallowing?

Answer 3

The larynx is elevated towards the soft palate
The epiglottis closes off the laryngeal inlet

Question 4

What movements happens in the vocal cords during phonation?

Answer 4

Vocal cords are in close approximation to each other and vibrate as air passes between them.
Vestibule open

Question 5

What happens in the effort closure of the glottis?

Answer 5

For example during weight lifting
Vocal cords are completely adducted
No passage of age, no vibration air may escape causing grunting

Question 6

What is the difference in the movements of the vocal cords between quite and forced respiration?

Answer 6

Quiet respiration - gap between vocal cords
Forced respiration - vocal cords are widely seperated,

Question 7

What is the clinical significant of the posterior cricoarytenoid muscle?

Answer 7

Rotates and the pulls arytenoud down laterally - abducts the vocal ligaments and opens the glottis
Only muscle to open the glottois
Paralysis results in flaccid closure of the glottis and suffocation

Question 8

The transverse and oblique arytenoids are known as the intrarytenoids.
What is their function?

Answer 8

Adduction of the vocal ligaments
Glottis narrowed

Question 9

What is the function of the lateral cricoarytenoid muscle?

Answer 9

Rotates arytenoid, vocal processes brough closer together, glottis is narrowed
Quiet respiration

Question 10

What is the function of the thyroarytenoids?

Answer 10

Contraction - shorten and thicken the vocal cord
Decrease the pitch of sound

Question 11

What is the funcation of the vocalis muscle?

Answer 11

Part of thyroarytenoid which attaches to the vocal ligament
Makes fine adjustments to tension in vocal ligaments - changes the timbre of voice

Question 12

What is the function of the cricothyroid muscle?

Answer 12

Contraction causes elongation and an increase in length and tension of the vocal ligament
This increases the pitch of sound

Question 13

What is adductive spasmodic dysphonia and how is it treated?

Answer 13

Paralysis of the posterior cricoarytenoid - usually on one side
Unable to open rima glottis for ventilation
Cause by basal ganglia stroke
Tx= injection of botulinum toxin into muscle which paralysed the muscle so it stays open.

Question 14

What is the phonatory mechanism of the larynx?

Answer 14

Occurs during expiration
Onest of speech - vocal cords are abducted
As you breath out pressure below the vocal cords increases
The pressure forces the vocal folds open - pressure decreases
Vocal cords are quickly adducted - laryngeal muscles and he bernouili effect
Repeats at 150-25oHz - releasing puffs of air - modified by lips, tongue and laryngeal muscles causing speech sounds.

Question 15

What muscles help close the laryngeal inlet during swallowing?
Their innervation

Answer 15

Aryepiglottic m - RLN - pull epiglottis down
Interarytenouds - RLN - close rima glottis.

The larynx is elevated by suprahyoid muscles:
Digastric - CN7 and V3
Mylohyoid - V3
Stylohyoid CN7
Geniohyoid - C1

Question 16

What movements occur during the sphincteric function of the larynx?

Answer 16

Larynx is elevated beneath the tongue
Epiglottis is lowered
Laryngeal inlet is closed
Vocal cords adducted
Ventilation suspended breafly
If fails - will cough

Question 17

What is the cough reflex in the larynx?

Answer 17

Foreign body detected by rich sensory innervation
Afferent signals to the brainstem
Intitiates a deep inspiration
Vocal fold tightly closed
Forecful expiration against the closed folds
Rapid and steep pressure increase below folds
Vocal folds suddenly opened/abducted.
Expiratory airfloe dislodges foreign body - spit or swallow.

Question 18

Describe the sensory innervation of the larynx

Answer 18

Internal branch of the superior laryngeal nerve -> supraglottic area
The recurrent laryngeal nerve - infraglottic area

Question 19

Describe the motor innervation of the larynx

Answer 19

The external laryngeal nerve (branch of superior LN) -> the cricothyroid muscles
The recurrent laryngeal nerve - internal laryngeal muscles

Question 20

Describe the arterial supply to the larynx

Answer 20

Blood supply to the larynx:
Superior thyroid artery -> superior laryngeal artery
Inferior thyroid artery -> inferior laryngeal artery

Question 21

Describe the venous drainage of the larynx

Answer 21

As the thyroid gland
Superior and middle thyroid veins -> internal jugular vein
Inferior thyroid veins -> brachiocephalic vein.