Larynx Flashcards
What is the larynx between?
- Oropharynx
- Trachea
What are the functions of the larynx?
- Transport of air
- Protective sphincter - closes the trachea e.g. if foreign object
- Phonation - production of sound (with other parts of the body- resonating chambers, tongue, mouth)
What vertebral level is the larynx?
- approx C3-C6
- Mobile so this can change
- Slightly higher in infants
Why is the fact that the larynx is higher in infants significant?
- Tip of the epiglottis is in contact with the soft palate
- Baby can breast feed and breathe at the same time
- This means they are mandatory nose breathers which means it is uncomfortable if the nose is blocked
What are the laryngeal cartilages?
- Epiglottis
- Thyroid
- Cricoid
- Arytenoid
- Corniculate
- Cuneiform
What is the epiglottis attached to?
- Thyroid cartilage by the thyroepiglottic ligament
- Hyoid by hyoepiglottic ligament
Describe the position of the epiglottis
- Projects upwards and backwards into the pharynx, beind the posterior part of the tongue
- Because of the tension of the ligaments, it goes back to the breathing position
Describe the parts of the thyroid cartilage
- Left and right laminae that join at the thyroid angle (laryngeal prominence = more prominent in males = Adams apple)
- Superior horns that attach to the hyoid
- Inferior horns that articulate with the cricoid
- Superior thyroid notch
- Oblique line for muscle attachment
Red arrow
Superior thyroid notch
Green arrow
Laryngeal prominence
Purple arrow
Oblique line
What is the difference in the laryngeal angle in men and women?
- Men = 90 degrees = more prominent
- Women = 120 degrees
Describe the cricoid cartilage
- Shape of a signet ring with lamina posteriorly
- Sloping shoulder on the lamina for arytenoid articulation
- Ridge for attachment of the oesophagus
- Depressions for attachment of the posterior crico arytenoid muscle
What does the cricoid cartilage articulate with?
- Arytenoids
- Thyroid
What do the arytenoids articulate with?
- Sloping shoulders of the cricoid lamina
- Corniculate cartilage superiorly
What are the parts of the arytenoid?
- Vocal process: anteriorly for the attachment of the vocal ligament
- Muscular process: posteriorly for the attachment of posterior and lateral crico-arytenoid muscles
Red arrow
Vocal process
1
Depression for the vestibular ligament
2
Depression for the attachment of the vocal muscle
Green arrow
Muscular process on the arytenoid
Describe the Thyro-hyoid membrane
- Extends between: Upper edges of the thyroid lamina, the superior horns and the body and the greater horns of the hyoid
- Thickened anteriorly and posteriorly as the median and lateral thyro-hyoid ligaments
- Hole on either side where it is pierced by the superior laryngeal vessels and superior laryngeal nerve
Describe the fibro-elastic membranes
- Formed from connective tissue under the laryngeal mucous membrane that stretches between laryngeal cartilages
- Separated by the laryngeal ventricle
- Superiorly: Quadrangular membrane
- Inferiorly: Conus elasticus
Red
Quadrangular membrane
Green
Conus elasticus
Black arrow
Laryngeal ventricle
What does the quadrangular membrane extend between?
Lateral aspects of the epiglottis, arytenoid and corniculate cartilage
What are the edges of the quadrangular membrane?
- Aryepiglottic fold (free edge)
- Vestibular ligamnet
Red arrow
Aryepiglottic fold
Green arrow
Vestibular ligament
Red arrow
aryepiglottic fold
Green arrow
Vestibular ligament
What is another name for conus elasticus?
Cricovocal membrane
What does the conus elasticus blend with anteriorly and why is it significant?
- Median cricothyroid ligament
- It is the site of emergency access to the airway- tracheotomy
Red arrow
Cricovocal membrane (conus elasticus)
Green arrow
Median cricothyroid membrane
What is the function of the vocal cords?
They control the laryngeal diameter for:
- Speech
- Coughing/sneezing (protective reflexes)
- Raising intra-abdominal pressure
What type of epithelium lines the upper respiratory tract?
Pseudostratified ciliated columnar epithelium
What type of epithelium lines the vocal cord?
Stratified squamous epithelium (to withstand the force of vibration