Larynx Flashcards
What is the function
Where is it
What level is it found at
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
Name the cartilage that supports the larynx
3 large
- thyroid
- cricoid
- epiglottis
3 small
- paired arytenoid
- paired cuneiform
- paired corniculate
Describe the thyroid cartilage
-structure
Describe the cricoid cartilage
-structure
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
Describe the epiglottis
-type of cartilage
Fibroelastic cartilage (leaf like)
- stem anchored into larynx
- leaf oriented upwards and back behind hyoid
- forms anterior part of the laryngeal inlet
Describe the arytenoid paired cartilage
Describe the corniculate paired cartilage
Describe the cuneiform paired cartilage
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
What are the 3 main ligaments
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
What are the 3 main membranes found here
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
What are the function of the extrinsic muscles
Supra and infrahyoid muscles move larynx up or down
Suprahyoid
- Mylohyoid
- Geniohyoid
- Stylohyoid
- Digastric
Infrahyoid
- Thyrohoid
- Omohyoid
- Sternohyoid
- Sternothyroid
What are the intrinsic muscles
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
What do the intrinsic muscles do
-3 functions
Open rima glottidis => allow passage of air
Close vestibule and rima => prevent aspiration during swallowing
Control tension of vocal folds for phonation
What is the neurovascular supply of the larynx
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
Describe the lymphatic drainage of the larynx
-how does this vary relative to the vocal folds
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
Describe the process behind phonation
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
