Larynx

Question 1

What is the function
Where is it
What level is it found at

Answer 1

Voice production, anterior air passageway linking pharynx to trachea

Sphincter to prevent food from entering trachea

C3-6
Inlet lies behind post third of tongue

Question 2

Name the cartilage that supports the larynx

Answer 2

3 large

• thyroid
• cricoid
• epiglottis

3 small

• paired arytenoid
• paired cuneiform
• paired corniculate

Question 3

Describe the thyroid cartilage
-structure

Describe the cricoid cartilage
-structure

Answer 3

Thyroid

• 2 plates joined anteriorly at midline
• in males, join is acute
• in females, join is obtuse
• thyroihyoid membrane above with aperture for int branch of sup laryngeal

Cricoid (C6)

• immediately below thyroid
• signet ring, encircles larynx

Question 4

Describe the epiglottis

-type of cartilage

Answer 4

Fibroelastic cartilage (leaf like)

• stem anchored into larynx
• leaf oriented upwards and back behind hyoid
• forms anterior part of the laryngeal inlet

Question 5

Describe the arytenoid paired cartilage
Describe the corniculate paired cartilage
Describe the cuneiform paired cartilage

Answer 5

Arytenoid

• pyramid shaped on posterior lamina of cricoid
• synovial joint between base and cricoid

Corniculate

• sit on the apices of arytenoid
• forms posterior part of laryngeal inlet

Cuneiform

• in the aryepiglottic fold
• above and anterior to corniculates
• forms lateral part of laryngeal inlet

Question 6

What are the 3 main ligaments

Answer 6

Vocal ligaments

• thick elastic fibres joining arytenoid to thyroid cartilage
• covered by mucous membrane, vocal folds

2 lateral ventricular ligaments

• from arytenoid cartilage to int lamina of thyroid cartilage
• ligaments surrounded by mucus membranes to form false vocal folds

Aryepiglottic ligament

• from arytenoid cartilage apices to lateral epiglottis
• forms the aryepiglotic fold

Question 7

What are the 3 main membranes found here

Answer 7

Thyrohyoid membrane

• fibroelastic sheet joining inf hyoid to sup thyroid cartilage
• lateral borders free and thickened

Quadrangular membrane

• layer of submucosa
• contains cuneiform cartilage
• superior border => aryepiglottic fold
• inferior border => false vocal fold

Cricothyroid membrane

• fibroelastic sheet
• between vocal folds and cricoid cartilage

Question 8

What are the function of the extrinsic muscles

Answer 8

Supra and infrahyoid muscles move larynx up or down

Suprahyoid

• Mylohyoid
• Geniohyoid
• Stylohyoid
• Digastric

Infrahyoid

• Thyrohoid
• Omohyoid
• Sternohyoid
• Sternothyroid

Question 9

What are the intrinsic muscles

Answer 9

Originate and insert into laryngeal cartilage

Posterior cricoarytenoid (cricoid to arytenoid cartilage
Lateral cricoarytenoid (lateral cricoid to arytenoid, oppose post)

Transverse and oblique arytenoid (between bases of arytenoids)
-above to Posterior cricoarytenoid

Vocalis/thyroarytenoid

• forms body of vocal folds
• parallel with vocal ligaments

Question 10

What do the intrinsic muscles do

-3 functions

Answer 10

Open rima glottidis => allow passage of air
Close vestibule and rima => prevent aspiration during swallowing
Control tension of vocal folds for phonation

Question 11

What is the neurovascular supply of the larynx

Answer 11

Nerves - via laryngeal nerves from vagus
Motor
-recurrent laryngeal => int larynx except cricothyroid
-ext laryngeal => cricothyroid

Sensory

• int laryngeal => above vocal fold
• recurrent laryngeal => below vocal fold

Artery

• sup/inf thyroid => sup/inf laryngeal
• inf laryngeal artery runs with inf laryngeal nerve

Vein
-laryngeal veins => sup/inf thyroid veins

Question 12

Describe the lymphatic drainage of the larynx

-how does this vary relative to the vocal folds

Answer 12

Submucosal lymphatic plexus drained by deep cervical nodes

Above vocal fold
-pierce thyrohyoid membrane => upper deep cervical nodes

Below vocal fold
-lower deep cervical lymph nodes

Question 13

Describe the process behind phonation

Answer 13

Takes place during expiration

Vocal folds adducted obstructing air flow => changes frequency of sound

Pressure builds up from below => forces folds apart allowing air to escape
-subglottal pressure, mass, tension on vocal ligaments => frequency