15. Functional Anatomy Of The Larynx Flashcards
What are the boarders of the larynx?
From the laryngeal inlet to the trachea at C6/lower boarder of the cricoid cartilage.
What route does inspired air take to the trachea?
Inspired air via oral cavity/nasopharynx.
Oropharynx.
Larynx.
Trachea.
What route does food take to the oesophagus?
Food via oral cavity.
Oropharynx.
Laryngopharynx.
Oesophagus.
What is the main function of the larynx?
To provide a protective sphincter for the lower respiratory tract.
What 3 single cartilages and 1 paired cartilages form the framework of the larynx?
3 single: Thyroid. Cricoid. Epiglottis. Paired: Arytenoid cartilages. (There are 2 others don't need to know).
What 4 membranes and ligaments connect the cartilages and the hyoid and help to give shape to the larynx?
Thyrohyoid membrane.
Cricothyroid ligament.
Cricotracheal membrane.
Quadrangular membrane.
Via what membrane can access to the airway be gained in an emergency if the patient cannot be incubated or ventilated (eg swelling to vocal cords)?
Cricothyroid membrane.
What forms the vestibular ligament (false vocal cord)?
Free lower border of the quadrangular membrane.
What forms the vocal ligament?
Thickened edge of the upper free border of the cricothyroid ligament.
What are the 3 regions of the larynx and what separates them?
Supraglottis.
Glottis.
Infraglottis.
Mucosal folds formed by ligaments/membranes and cartilages.
What type of epithelium lines the larynx?
Pseudostratified ciliated columnar epithelium (is a component of the respiratory tract).
What landmark can help you orientate yourself when looking at the epiglottis?
Point of rima glottis is anterior.
What are the two broad functions of the laryngeal muscles?
Alter the size and shape of the inlet in breathing and swallowing.
Move position to alter tension in the vocal cords in phonation and coughing.
What is the only muscle of all the intrinsic muscles of the larynx that abducts (opens) the vocal cords?
Posterior cricoarytenoid.
What is the narrowest part of the larynx?
Glottis.
What determines the position of the true vocal cords and therefore size of the rina glottis apeture?
Position of arytenoids on cricoid cartilage.
What nerve supplies all of the laryngeal muscles except the cricothyroid muscle?
Recurrent laryngeal nerve of CN X vagus.
How do the vocal cords move during inspiration and expiration?
Vocal cords abduct - glottis wide open.
How do the vocal cords move during phonation?
Adduct - expired air is forced through closely adducted vocal cords to vibrate a column of air.
How do the vocal cords move during a cough?
Powerfully adduct, intrathoracic pressure builds, then cords suddenly abduct.
How can the pitch of vocal sound be altered?
Cricothyroid muscle alters the tension and length of true vocal cords - vocal cords taught for high-pitched sounds, cords relaxed for low-pitched sounds.
What nerve innervates the cricothyroid muscle?
External branch of the superior laryngeal nerve of CN X vagus.
What does injury of the external laryngeal nerve (which gives off the superior laryngeal artery) cause eg in thyroid surgery due to close proximity to the superior thyroid artery? And why?
Hoarseness of voice especially when attempting high pitched sounds. Innervates the cricothyroid muscle which alters tension in the vocal chords.
How does the larynx close in swallowing to protect the airways?
Contraction of aryepiglottic muscles acts to narrow the laryngeal inlet and pull down the epiglottis, assisted by elevation of the larynx by the pharyngeal muscles and suprahyoid muscles pulling the larynx up and forward. This results in closure of the glottis.
