Anatomy of the larynx Flashcards
Identify the neck fascial compartments in the image.
Purple: pretracheal.
Green: investing
Orange: prevertebral
Red: carotid sheaths x2
Identify the labelled structures
Left: strap muscles
Right from top- mandible, hyoid bone, left clavicle, manubrium
Where are the strap muscles located and what can they function as?
Pretracheal fascia, accessory muscles of inspiration during forced breathing
What vertebral level is the larynx found at?
C4-C6
Which structures are found within the carotid sheath?
Internal jugular vein, internal and common carotid arteries, deep cervical lymph nodes, vagus nerve
What are the vertebral levels of:
a) the hyoid bone
b) the upper border of the thyroid cartilage
c) the cricoid cartilage
a) C3
b) C4
c) C6
What happens at the level of the C6 vertebra?
Larynx becomes trachea; pharynx becomes oesophagus
What are the functions of the larynx?
Cartilages help maintain URT patency; vocal cords produce sound; helps to prevent foreign body entrance into the LRT
What are the “skeletal” components of the larynx?
The epiglottis; the thyroid cartilage; the cricoid cartilage; artyenoid cartilage; corniculate and cuneiform cartilages.
What is different about the epiglottis compared to the rest of the skeletal components of the larynx?
Composed of elastic cartilage rather than hyaline
Identify the labelled structures
Clockwise from top:
Laryngeal prominence
Inner aspect of thyroid cartilage
Vocal process of artyenoid cartilage
Muscular process of artyenoid cartilage
Right and left artyenoid cartilages
Cricoid cartilage
Rima glottidis
Right vocal cord
Where do the vocal cords attach?
Inner aspect of thyroid cartilage and vocal process of artyenoid cartilage
In what situation would cricoid pressure be applied? Why does this only work at this particular area?
In emergency anaethesia- prevents regurgitation/aspiration but maintains patency. Only works here because this is the only point the larynx is a complete ring
When intubating why is it important to avoid placing the tube in a main bronchus?
Will only inflate ipsilateral lung; contralateral lung will collapse
What is the space betwen the posterior tongue and the epiglottis called?
Vallecula
What kind of mucosa is found in the larynx, and what is the exception to this? Why is this the case?
Respiratory with the exception of vocal folds, which is stratified squamous- protective
What are the characteristic features of respiratory mucosa?
Mucus production and cilia
How does the general sensory nerve supply to the larynx differ posterior to the vocal cords, compared to inferior?
Posterior: supplied by superior laryngeal branches of the vagus nerve. Vocal cords and inferior to the vocal cords- recurrent laryngeal branch of the vagus nerve.
What is the motor supply to the larynx?
Branches of the vagus nerve
How do the intrinsic muscles of the larynx work to move the vocal cords?
Attach to cartilage which in turn move the vocal cords
What are the four categories of intrinsic muscle of the larynx?
Tensors, relaxers, abductors, adductors
What are the four stages in voice production?
- Inspiration using the diaphragm (phrenic nerve) and intercostals
- Controlled expiration
- Phonation in the vocal cords
- Articulation in the mouth (tongue and lips) and the nasal cavity
How is the function of the vagus nerve in the palate, pharynx and larynx tested?
- Swallowing water- does the larynx move up? Do they splutter (suggests abnormal swallow and abnormal cough)
- Listen to the patient speak- hoarseness may indicate dysfunction of the intrinsic muscles of the larynx
- Ask to cough- is the cough powerful (also requires functioning nerve supply to diaphragm, abdominals etc)
