The Larynx Flashcards
What structures does the larynx connect?
The inferior oropharynx with the trachea
Where does the larynx extend from and to?
Laryngeal inlet to the level of the inferior border of the cricoid cartilage
Function of the larynx?
Guard the air passages, especially during swallowing, where it serves as a sphincter of the lower resp tract
What is the laryngeal skeleton made up of?
Hyoid bone
9 cartilages
Name the cartilages of the larynx
3 unpaired
- epiglottis
- thyroid
- cricoid
Paired
- arytenoid cartilage
- corniculate cartilage
- cuneiform cartilage
What is the epiglottis attached to?
Back of the hyoid bone and thyroid cartilage by ligaments
What level is the upper border of the thyroid cartilage at?
C4
What important anatomical landmarks are there at the superior border of the thyroid cartilage?
Bifurcation of the common carotid artery
Level of the carotid body
What shape is the cricoid cartilage said to be?
Signet ring shaped
What vertebral level does the cricoid cartilage mark?
C6
What articulates with the two articular facets on either side of the cricoid cartilage?
Inferior horn of thyroid cartilage
Arytenoid cartilage
What shape is the arytenoid cartilage said to be?
Pyramid
What is on the anterior and lateral sides of the arytenoid cartilage?
Anterior - vocal process
Lateral - muscular process
Which cartilage is important for vocal cord ligament?
Arytenoid cartilage
Where does the cricovocal ligament/membrane run between?
Deep surface of the angle of the thyroid cartilage to the vocal process of the arytenoid cartilage
What are the divisions of the internal larynx?
Features of each division?
Supraglottic space
- laryngeal inlet
- vestibular folds (false vocal cords)
Glottis
- vocal cords
- rima glottis (space between vocal cords)
Subglottic space
Which groups can the laryngeal muscles be divided into?
Extrinsic and intrinsic muscles
What is the function of the extrinsic muscles of the larynx?
Move the entire larynx
- infrahyoid muscles depress it
- suprahyoid muscles elevate it
Function of the intrinsic muscles of the larynx?
Open and close the glottis by acting on the vocal folds
Help to close the laryngeal inlet by acting on the aryepiglottic folds
Innervation of the intrinsic muscles?
Recurrent laryngeal nerve
Except for the cricothyroid muscle supplied by the external laryngeal nerve
What are the layers of the vocal cords?
Stratified squamous epithelium
Vocal ligament
Vocalis muscle
What are the implications of a lack of submucosa of the vocal cords?
Vocal cords look pearly white on laryngoscopy
No oedema during infections
Delayed spread of carcinoma of vocal cords
Which muscles carry out abduction of the vocal cords?
Posterior cricoarytenoid
Which muscles carry out adduction of the vocal cords?
Lateral cricoarytenoid
Cricothyroid
The branches of which cranial nerve is the larynx innervated by?
Branches of the vagus nerve
Function of the superior laryngeal nerve in the larynx?
- internal laryngeal nerve - sensory to the larynx above the true vocal cord
- external laryngeal nerve - motor to cricothyroid muscle
Function of the recurrent laryngeal nerve?
Sensory to below the true vocal cord
Which vessels do the right and left recurrent laryngeal nerves loop around?
Right - descends to T2 and loops around subclavian artery
Left - descends to T4 and loops around the arch of the aorta
What does the recurrent laryngeal nerve run upwards in?
Tracheo-oesophageal groove
Causes of hoarse voice?
Recurrent laryngeal nerve palsy
- aortic aneurysm
- apical lung tumour
- bronchial carcinoma (only on left as right doesn’t go low enough)
Laryngitis (viral or streptococcal)
GORD
Benign nodules on vocal cords
Blood supply to the larynx?
External carotid artery - superior thyroid artery - superior laryngeal artery
Subclavian artery - inferior thyroid artery - inferior laryngeal artery
Venous drainage of the larynx?
Superior laryngeal vein - superior thyroid vein - internal jugular
Inferior laryngeal vein - inferior thyroid vein - left brachiocephalic vein
What can an upper airway/laryngeal obstruction be caused by?
Laryngeal oedema
-infection - acute epiglottitis, croup, anaphylaxis
Inhalation of a foreign body
Tumours
Where is a cricothyroidotomy performed?
In an emergency situation
Opened through the cricothyroid membrane
