Larynx Flashcards
Where does the larynx sit?
- between the oropharynx and the trachea
- between C3-6
- hangs under hyoid
What is the larynx?
membranous fibro-elastic tube suspended between cartilages
What are the 3 main functions of the larynx?
- transport of air
- protective sphincter
- phonation (sound)
What is the anatomical difference in the larynx of newborns?
slightly higher
What are the laryngeal cartilages? (know how to label diagram)
- epiglottis
- thyroid
- cricoid
- arytenoid
- corniculate
- cuneiform
What are the attachments of the epiglottis?
- thyroid cartilage by thyroepiglottic ligament
- hyoid bone by hyoepiglottic ligament
Describe what makes up the thyroid cartilage
- left and right laminae
- superior horns attached to hyoid bone
- inferior horns attached to cricoid cartilage
- superior thyroid notch
- oblique line for muscle attachment
- thyroid angle which is the laryngeal prominence
What does the cricoid thyroid articulate with?
- arytenoids and thyroid
- has sloping shoulder on lamina for arytenoid articulation
- ridge posteriorly for attachment with oesophagus
- depression posteriorly for attachment of crico-arytenoid muscle
What does the arytenoid cartilage articulate with?
- artciulates with sloping shoulder of cricoid and lamina
- superiorly articulates with corniculate
- vocal process anteriorly for vocal ligament
- muscular process posterior for posterior and lateral crico-arytenoid muscles
- 2 depressions anteriorly for vestibular ligament and vocalis muscle
Where is the thyro-hyoid membrane located?
between upper edges of thyroid laminae and superior horns, and greater horns of hyoid
What are the important features of the thyro-hyoid membrane?
- thickened anteriorly and posterior to become median and lateral thyro-hyoid ligaments
- pierced by superior laryngeal vessels and superior laryngeal nerve
What are the orders of the membranes from superficial to deep?
laryngeal mucus membrane then fibro-elastic membrane then cartilaginous skeleton
What separates the fibro-elastic membrane and what is it divided into?
- fibro-elastic membranes separated by laryngeal ventricle
- superiorly is the quadrangular membrane
- inferiorly is conus elasticus
What does the quadrangular membrane cover and what are the edges?
- between lateral aspects of epiglottis, arytenoid and corniculate cartilages
- edges: aryepiglottic fold and vestibular fold
What structures form the vestibular fold?
vestibular ligament and mucous membrane
What is the clinical significance of the median cricothyroid ligament?
site of emergency access to airway (tracheotomy)
What are the 2 parts of the conus elasticus?
- cricovocal membrane
- median cricothyroid ligament
What is the function of the vocal/vestibular cord?
- speech
- coughing/sneezing
- raising the intra-abdominal pressure
What is contained within the laryngeal cavity?
- vesibule: between laryngeal inlet and vestibular folds
- laryngeal ventricle: recess between vestibuar and vocal folds leading to the saccule
- infraglottic cavity: between vocal folds and trachea
What does the saccule do?
lubricates the vocal folds
What is the boundary the laryngeal inlet?
aryepiglottic folds
What is the rima glottis?
opening between the vocal cords and muscular processes of the arytenoid
What are the functions of the muscles of the larynx?
controls the position of the larynx to:
- alter laryngeal diameter to allow passage of air only
- control airflow for speech
- raise intra-abdominal pressure
What are the extrinsic laryngeal muscles?
- suprahyoid
- infrahyoid
What are the functions of the extrinsic laryngeal muscles?
- arrange the position of the larynx
- facilitate closing of laryngeal inlet
What are the functions of the intrinsic muscles?
- adjust length/tension of vocal ligaments
- open and close rima glottis
- control inner dimensions of vestibule
- facilitate closing of laryngeal inlet
Where are the intrinsic laryngeal muscles?
extend between laryngeal cartilages
What extrinsic laryngeal muscles elevate the pharynx?
- salpingopharyngeus
- palatopharyngeus
- stylopharyngeus
What extrinsic laryngeal muscles elevate the larynx?
- stylohyoid
- mylohyoid
- geniohyoid
- thyrohyoid
- digastric
What extrinsic laryngeal muscles depress the larynx?
- sternothyroid
- thyrohyoid
- stylohyoid
What laryngeal muscles close the laryngeal inlet?
- salpingopharyngeus
- palatopharyngeus
- stylopharyngeus
- stylohyoid
- aryepiglottic muscle (purse string)
- thyro-epiglottic muscle (superior fibres)
Describe how the laryngeal inlet opens
- larynx descends by elastic recoil
- hypoepiglottic ligament
What muscle opens the vocal folds/rima glottis?
posterior crico-arytenoid muscle
What muscles close the vocal folds/rima glottis?
- inferior fibres of thyro-arytenoid
- lateral crico-arytenoid
- transverse arytenoid
What lengthens the vocal folds?
- rocking of the thyroid cartilage backwards and forwards at cricothyroid joint
- cricothyroid muscles lengthens it
What muscle increases tension of vocal folds to raise pitch of voice?
vocalis muscle (part of thyro-arytenoid)
What shape is the rima glottis from quiet to forced inspiration?
it goes from triangular to rhomboid
What can be seen during a laryngoscopy of phonation?
- vocal folds adduct
- air forced through vocal folds causes vibration
- cord length and tension altered
What can be seen during a laryngoscopy of effort closure?
- vocal and vestibular folds adduct
- airway closed by lateral crico-arytenoid and transverse arytenoid muscles in valsalva maneover
Describe what happens during swallowing
- laryngeal elevation
- laryngeal inlet closes by epiglottis
- after larynx descends and epiglottis springs back hyoepiglottic ligament
Describe the arterial supply of the larynx
- superior laryngeal a (from superior thyroid a)
- inferior laryngeal a (from inferior thyroid a)
Describe venous drainage of larynx
- superior laryngeal v (from superior thyroid v from IJV)
- inferior laryngeal v (from inferior thyroid v from BCV)
- inferior thyroid veins at risk during tracheostomy
What is the lymphatic drainage of the larynx?
- above vocal cord: superior deep cervical lymph nodes
- below vocal cord:
- prelaryngeal, pretracheal
- inferior deep cervical
- supraclavicular
Describe the neural supply of the larynx
- superior laryngeal nerve:
- internal branch: sensation of larynx down to above vocal folds
- external branch: cricothyroid muscle
- inferior laryngeal nerve (from recurrent larymgeal nerve from vagus)
- recurrent laryngeal nerve:
- all intrinsic muscles of larynx (except cricothyroid)
- sensation to vocal cords and larynx below
