What is the larynx?
part of the respiratory tract between oropharynz and trachea
What is the larynx?
membranous (fibro-elastic) tube suspended between cartilages and hyoid bone
What are the 3 functions of the larynx?
- transport of air
- protective sphincter
Where is the larynx located?
Between C3 and C6 vertebrae
Where is the larynx in newborns and infants?
Where does the larynx hang?
under the hyoid bone
Describe the skeleton of the larynx
made out of cartilage connected to each other by ligaments and membranes
What are the names of ech of the laryngeal cartilages?
- Red = Epiglottis
- Blue = thyroid
- Green = cricoid
- Purple = arytenoid
- Black = corniculate
What are the 3 single laryngeal cartilages?
What is the only elastic laryngeal cartilage?
What are most of the laryngeal cartilages made of?
Where is the epiglottis found?
projects upwards and backwards into the pharynx, behind the posterior part of the tongue
How is the epiglottis attached to the thyroid cartilage?
How is the epiglottis attached to the hyoid cartilage?
What is the biggest laryngeal cartilage and what are its main features?
- Right and left laminae
- Superior and inferior horns
What do the superior horns of the thyroid cartilage attach to?
What do the inferior horns of the thyroid cartilage articulate with?
Name what each of the arrows is indicating to -
Red = superior thyroid notch
Green = laryngeal prominence
Purple = Oblique line
What is the thyroid angle determined by? And how does it differ in males and females?
More acute (closer to 90degrees) in males than females
What is the function of the oblique line of the thyroid cartilage?
for muscle attachment
What is the shape of the cricoid cartilage?
Shape of a signet ring with the lamina posteriorly
What does the cricoid cartilage articulate with?
arytenoids and the thyroid
What is the function of the ‘sloping shoulder’ on the lamina of the cricoid cartilage?
for arytenoid articulation
What is the function of the ridge on the cricoid cartilage?
attachment of the oesphagus
What is the function of the depressions on the cricoid cartilage?
for attachment of posterior crico-arytenoid muscle
What does the arytenoid cartilage articulate with?
sloping shoulder of cricoid lamina and superiorly with corniculate cartilage
Name what each arrow and number is indicating -
Red = vocal process
Green = Muscular Process
1 = Depression for vestibular ligament
2 = depression for the attachment of vocalis
Where is the vocal process located and what attaches to it?
Anteriorly, for the attachment of the vocal ligament
Where is the muscular process located and what is its attachments?
posteriorly, for the attachment of posterior and lateral crico-arytenoid muscles
Where does the thyro-hyoid membrane extend?
Between upper edges of the thyroid lamina and superior horn and the body and greater horns of the hyoid bone
What does the thyro-hyoid membrane form when it is thickened anteriorly and posteriorly?
Medial and lateral hyoid ligaments
What is the thyro-hyoid membrane pierced by?
superior laryngeal vessels and internal branch of the superior laryngeal nerve
Red = median thyro-hyoid ligament
Green = Lateral thyro-hyoid ligament
Black = where the thryo-hyoid membrane is pierced
What is the fibro-elastic membrane?
elastic connective tissue underneath the larnygeal membrane that stretches the laryngeal cartilages
What are the fibro-elastic membranes separated by?
What is the superior fibro-elastic membrane?
–> cape over the epiglottis
What is the inferior fibro-elastic membrane?
Conus elasticus (triangular)
Where does the qudrangular membrane extend?
between lateral aspects of the epiglottis, arytenoid and corniculate cartilages
What are the edges of the quadrangular membrane?
- Aryepiglottic fold
- vestibular ligament
What is the vestibular ligament when it is covered by a mucous membrane?
Red = quadrangular membrane
Black = laryngeal ventricle
Green = conus elasticus
red = aryepiglottic fold
green = vestibular ligament
What is another name for the conus elasticus?
What does conus elasticus blend with anteriorly?
medial cricothyroid ligament
What is the main clinical function of the medial cricothyroid ligament?
site of emergency access to the airwat (tracheostomy)
Red = crico-vocal membrane
Green = median cricothyroid ligament
What do the vocal cords control laryngeal diameter for?
- raising the intra-abdominal pressure
What type of epithelium are the vocal cords lined with?
stratified squamous epithelium
What are the 3 parts of the laryngeal cavity?
- the vestibule
- laryngeal ventricle
- infra-glottic cavity
Where is the vestibule located?
Between the laryngeal inlet and the vestibular folds
Where is the laryngeal ventricle?
The recess between the vestibular and vocal folds
What does the laryngeal ventricle lead to?
What is the function of the saccule?
Provides lubricating mucus fir the vocal folds
Where is the infra-glottic cavity located?
between the vocal folds and the trachea
What is another name for the laryngeal inlet?
What is the laryngeal inlet bound by?
What is the rima glottis?
opening between vocal cords and vocal processes of the arytenoid
Green = laryngeal inlet
Red = Rima Glottis
What is the function of the larynx?
Its position is controlled by muscles:
- Alter laryngeal diameters to allow the passage of air only
- control airflow for speech
- raise intra-abdominal pressure
What is the function of the extrinsic laryngeal muscles?
- Arrange the position of the larynx as a whole
- facilitate closing of the laryngeal inlet
What are the 2 groups of extrinsic laryngeal muscles?
suprahyoid and infrahyoid muscles
Where do intrinsic laryngeal muscles extend?
between laryngeal cartilages
What is the function of the intrinsic laryngeal muscles?
- adjust the length and tension of the vocal ligaments
- open and close the rima glottis (airflow)
- control the inner dimensions of the vestibule
- facilitate closing of the laryngeal inlet
Where do the extrinsic laryngeal muscles extend?
Between the skull to larynx and pharynx
Name the 8 elevator extrinsic laryngeal muscles
Name the 3 depressor extrinsic laryngeal muscles
Red = diagastric
Black = mylohyoid
Blue = sternothyroid
Green = thyrohyoid
What are the main contributers to closing of the laryngeal inlet?
What are the 3 functions of the intrinisic laryngeal muscles?
- Open/close the laryngeal inlet (aryepiglottic folds)
- Open/close the rima glottidis (and rima vestibuli) - arytenoid gliding anf rotation
- Lengthen the vocal folds - “rocking” at cricothyroid joints or increase tension
Green = stylopharyngeus
red = stylohyoid
blue = salpingopharyngeus
purple = palatopharyngeus
What intrinsic muscles close the laryngeal inlet?
- Ary-epiglottic muscles act like a “pyrse string”
- Superior fibres of thyro-arytenoid muscle (thyro-epiglottic muscle)
What opens the laryngeal inlet?
Descent of the larynx (and pharynx) by elastic recoil
(hyo-epiglottic ligament = no contractile ability)
What is the ONLY muscle that opens the rima glottis/vocal folds
posterior crico-arytenoid muscle
What muscles close the vocal folds and rima glottis?
- Inferior fibres of thyro-arytenoid
- Lateral crico-arytenoid
- Transverse arytenoid
Red = aryepiglottic musclrs
Blue = thyro-epiglottic muscle
Where is thyroid cartilage rocked backwards and forwards?
What is the function of the cricothyroid muscles?
Lengthen the vocal folds or ligaments
What muscle alters the tension of the vocal ligaments? And what is the result of this?
increasing tension raises the pitch of the voice and decreasing it lowers the pitch
blue = thyro-arytenoid
red = lateral crico-arytenoid
green = transverse arytenoid
Red = vocalis muscle which is part of the thyroarytenoid muscle (blue)
what occurs at the laryngeal inlet during quiet respiration?
rima is triangular
what occurs at the laryngeal inlet during forced inspiration
- rima is rhomboid
- rima is widely opened by posterior crico-arytenoid externally rotating the arytenoids
what occurs at the laryngeal inlet during phonation?
- vocal folds are adducted
- air forced through vocal folds causes vibration
- cord length anf tension are latered by cricothyroid, thyro-arytenoid and vocalis muscle
what occurs at the laryngeal inlet during effort closure?
What occurs during swallowing?
- laryngeal elevation
- closure of laryngeal inlet by epiglottis
What ligament causes the epiglottis to spring back into its normal position?
What is the arterial supply of the larynx?
- superior laryngeal (green)
- inferior laryngeal (blue)
**Both are branches of the respective thyroid artery
What is the venous drainage of the larynx?
- Superior laryngeal (black) –> superior thyroid –> internal jugular vein
- Inferior laryngeal (green) –> inferior thyroid vein –> brachiocephalic vein
What is the lymphatic drainage above the vocal cords?
superior deep cervical lymph nodes
What is the lymphatic drainage below the vocal cord
- inferior deep cervical
black = superior deep cervical
blue = pretracheal
green = inferior deep cervical
What is the neural supply of the larynx?
- superior laryngeal nerve; branch of the vagus nerve
- recurrent laryngeal nerve
What are the functions of the internal branch of the superior laryngeal nerve? And what is it accompanied by?
- sensation of the larynx down to just above the vocal folds
Accompanied by the superior laryngeal artery
What is the progession of the vagus nerve?
vagus –> recurrent laryngeal –> inferior laryngeal
What is the inferior laryngeal nerve accompanied by?
inferior laryngeal artery
What does the recurrent laryngeal nerve supply?
- all muscles of the larynx except cricothyroid
- sensation to the vocal cords and larynx below