L6 Anatomy of Larynx Flashcards
What are the function of larynx ?
- Guarding the airways during swallowing ( most important )
2. Organ of voice production with the help of lungs and others
What is the structure and position of larynx ?
Structure : made of 9 cartilages connected by ligaments and membranes
Position : from C3 to C6 however it is extend to C2 ( axis vertebra ) or C1 ( atlas vertebra ) in children making them able to swallow and breath in the same time
What is the component of laryngeal wall ?
- Mucosa ( inner )
- Submucosa
- CT
- Muscles
- Cartilages ( outer )
What are the cartilages of larynx? Which are important (i) which is not (n) ?
3 unpaired (=3)
- Thyroid (i)
- Cricoid (i)
- Epiglottis (i)
3 paired (=6)
- Artynoid (i)
- Corniculate (n)
- Cuniform (n)
What is the thyroid cartilage structure? To what does it attach ?
Thyroid cartilage is the largest hyaline cartilage
Structure:-
Anteriorly :
- 2 laminae-fuse anteriorly to form the laryngeal prominence (Adam’s apple)
Posteriorly:
Two lamellar projections —
What is the structure of cricoid cartilage ?
It is a hyaline ring that has :
- arch anteriorly
- lamella posteriorly ( artynoid cartilage is attached to the upper boarder to of the lamellar )
What is the structure of artynoid cartilage ?
It is made by two types of cartilages:
- lower part … hyaline
- upper part … elastic ( which articulate with the elastic corniculate )
Its movement ( rotation or gliding ) will occur as the rima glottides is changing its shape
What does the epiglottis made of ?
It is made of :
- Elastic cartilage
- Mucous membrane
What is the position of epiglottis?
- Upper end is free ( which will be bent during swallowing to protect air passages )
- Lower end is attached to the thyroid
- Attached to the hyoid bone by hyo-epiglottic membrane
What are the surfaces of epiglottis and their histology ?
- Anterior ( lingual ) :
- it is stratified squamous epithelium - Posterior ( pharyngeal ) :
- it is psudo-stratified columnar epithelium with pores for gland’s secretion
What does the interior of larynx is made of : ( 3 parts)
- Vestibule
- Middle part / laryngeal ventricle ( the narrow space between upper vestibular fold and lower vocal folds )
- Infra-glottic part
What is the fibro-elastic membrane ? And what is its structure ?
It is sub-mucosal fibro-elastic membrane that divides into two parts :
1. Upper ( in vestibular part ) —
What does the glottis is made of ?
- Vocal processes of artynoid cartilage
- Vocal ligaments
- Rima glottides
What does the rima glottides is made of ? And what is its function ?
Anteriorly : attached to thyroid cartilage
Posteriorly: attached to vocal processes of artynoid cartilage
And the vocal folds
It is involved in determination of voice pitch
What determines the pitch of the voice ?
- Tension of vocal folds
- Shape of rima glottides
- The force of air expiration
What is the histology of the larynx ?
- Generally it psudo-stratified columnar epithelium ( resp. epithelium) similar to the posterior surface of the epiglottis
- when you reach the vestibular folds it can be stratified squamous
- in the vestibule it is stratified columnar
- when you reach the vocal folds it is always stratified squamous ( as cuboidal and columnar will be damaged with the vibrations )
- as you going down it becomes stratified columnar then psudo-stratified columnar (resp. epithelium )
What is the components of lamina propria in larynx ?
- loose CT
- glands
However, in the vocal folds :
- dense CT ( reinke space )
What are the muscles of larynx?
- Crico-thyroid
- Thyro-artynoid
- Vocalis
- Posterior crico-artynoid
- Lateral crico artynoid
- Transverse artynoid
- Oblique artynoid
All of them are innervated by the recurrent (inferior ) laryngeal nerve of the vagus except the crico-thyroid which is innervated by the external ( superior ) laryngeal nerve of the vagus
What is the diffrence between thyro-artynoid and vocalis ?
They differ in their attachment to arytenoid cartilage
- Thyro-arytenoid is more lateral and attaches to the anterior part of arytenoid cartilage
- vocalis is more medial and attaches to the aryteoid muscle by its vocal muscle
Bothe relaxes the vocal ligament ( vocalis relax posterior part and stretch the anterior part )
What is the function of crico-thyroid muscle ?
It will stretch the vocal ligament as it will will pull the thyroid cartilage away
What is the difference between Posterior and lateral crico-arytenoids ?
Posterior crico-arytenoids :
Attachment: from (posterior part of cricoid lamina ) to the ( posterior part of muscular process )
Action : abduction of vocal lig. by moving arytenoid and opening the rima glottides
Lateral crico-arytenoids :
Attachment: from ( cricoid arch ) to the ( anterior part of muscular process )
Action : adduction of vocal lig. Without moving arytenoid process
Their actions
What is the difference between lateral crico-arytenoid muscle and oblique/transverse arytenoid muscle ?
Both will adduct the vocal ligament, however :
Lateral crico-arytenoid —> by moving inter-ligamentous parts only
oblique/transverse arytenoid —
What are the muscles that close (narrow) the larynx inlet ? What will open it ?
Muscles that will close it :
- Oblique and transverse arytenoid muscle
- Thyro-epiglottis
- Ary-epiglottis
- Lateral crico-arytenoid muscle
Muscles that will open it :
1. Thyro-arytenoid muscle
What are the Variations in shape of the rima glottidis during different conditions ?
Go to the note
What is the Blood supply, (sensory) nerve supply and lymphatic drainage of larynx
BLOOD SUPPLY :
- sup. and inf. laryngeal artery and vien which are branches of superior and inferior thyroid artery
SENSORY INNERVATION :
- above vocal fold : internal laryngeal
- below vocal fold : inferior laryngeal
LYMPHATIC DRAINAGE:
- above vocal fold: superior deep cervical lymph nodes
- below vocal fold : inferior deep cervical lymph nodes
Why right laryngeal nerve is more affected than left ? And how ?
As the left is more vertical and hidden between the trachea and esophagus
Normally, inferior thyroid artery and inferior laryngeal nerve ( mostly right) are near the thyroid gland,
So during surgery and when there is a need to ligate the inferior thyroid artery it should be ligated away from the thyroid gland to prevent the injury the inferior laryngeal nerve .
Which action is damaged and healed first ?
Normally, abduction is damaged first and healed lastly
