The Larynx Flashcards
State the components of the laryngeal skeleton
** Cartilages **
* 3 single *
-thyroid cartilage
- cricoid cartilage
- epiglottis
- 3 paired*
- Arytenoid
- Corniculate
- Cuneiform
Discuss the thyroid cartilage
•Largest.
•Formed by 2 laminae.
• Each lamina has superior and inferior horn.
•Has oblique line for muscle attachment.
•The upper border forms the thyroid notch.
•Laryngeal prominence( Adam’s apple) lies below thyroid notch.
•Thus vocal cord is longer in females than males because the prominence is projecting more in males.
Discuss the cricoid cartilage.
Ring shaped.
Has narrow anterior arch and wide posterior arch.
Forms cricothyroid and cricoarytenoid joints.
State the types and actions of the cricoid cartilage joints.
1. Cricothyroid joint
- synovial, hinge
- adjusts the tension of the vocal cord.
-permits rotatory (on inferior Cornua of thyroid cartilage) and gliding( in different directions of the thyroid cornua) movements.
2. Cricoarytenoid joints
- synovial, ball
- permits adduction and abduction of vocal cord(rotatory)
- gliding movements, one arytenoid glides towards the other or away from it, thus closing or opening the posterior part of glottis.
Discuss the arytenoid cartilage
Pyramidal in shape.
It’s apex is related to the corniculate cartilage.
It has 2 processes:
1. * Muscular process*
- lateral
- attachment of muscles
2. * Vocal process*
- anterior
- attachment of vocal cord
Name the membranes of the larynx
3 external
1. Thyrohyoid membrane- pierced by internal Laryngeal nerve and superior laryngeal artery and vein
#2. Median cricothyroid membrane
3. Cricotracheal membrane
2 internal membranes - beneath mucous membrane
# Cricovocal(conus elasticus)
1.Upper part: quadrate/quadrangular membrane - between epiglottis and arytenoid.
• upper border forms aryepiglottic fold, lower border forms vestibular fold.
- Lower part: cricothyroid membrane
• upper border forms vocal fold/ ligament
Name the spaces formed by the internal membranes
1. Rima vestibuli- between the vestibular folds.
- above and wider
2. Rima glottidis- between the vocal folds.
State the boundaries of the laryngeal inlet
Communication between pharynx and laryngeal cavity.
** Anterior: -epiglottis
** Posterior:- arytenoid cartilage and interarytenoid fold.
** Sides:** - aryepiglottic fold
Name the features of the laryngeal cavity
** 2 folds on each side**
1. Vestibular fold- above
2. Vocal fold- below
2 spaces in the midline
1. Rima vestibuli - between vestibular folds.
2. Rima glottidis - between vocal folds.
** 3 compartments**
1. Vestibule/ supraglottic space - above vestibular fold.
2. Ventricle - between vestibular and vocal folds
3. Infraglottic space - below vocal fold.
What are the functions of the of the larynx
- Respiration- in inspiration vocal cords are abducted to open rima glottidis.
- Phonation- vocal cords are adducted to force air between the two cords and produce sound
- Protection by epiglottis- closes Laryngeal inlet during swallowing.
- Protection by cough reflex.
State the components and action of the extrinsic laryngeal musculature.
** Extrinsic muscles**
#* Elevators*- suprahyoid muscles
1. Mylohyoid
2. Geniohyoid
3. Stylohyoid
4. Digastric
V# palatopharyngeus, salphingopharyngeus, stylopharyngeus, thyrohyoid
- Depressors*- infrahyoid muscles
#1. Sternohyoid- Sternothyroid
#3. Omohyoid
- Sternothyroid
State the components and action of the intrinsic laryngeal musculature.
** muscles acting on the vocal cord**
1. Abduct- posterior cricoarytenoid muscles.
2. Adduct- lateral cricoarytenoid and transverse arytenoid/ interarytenoid.
3. Tense(elongate)- cricothyroid; increase pitch.
4. Relax(shorten): vocalis?? and thyro-arytenoid.
** Muscles acting on the laryngeal inlet**
1. Open- thyroepiglotticus
2. Close- aryepiglotticus and oblique arytenoid
Describe the nerve supply of the larynx
1. Superior laryngeal nerve has two branches:
• external laryngeal(motor)- supplies cricothyroid muscle
• internal laryngeal(sensory above vocal cord)- pierces thyroid membrane to supply mucous membrane
2. Recurrent laryngeal nerve(sensory below vocal cord)
• supplies all the muscles of the larynx except cricothyroid. It supplies mucous membrane through the vocal cord.
* both from vagus*
Discuss laryngeal nerve paralysis
Causes:
1. Thyroid and parathyroid gland surgery.
2. Lesion in nucleus ambiguus- laterally medullary syndrome
** Superior laryngeal.**
1. Paralysis of cricothyroid muscle
2. Sensory loss above vocal cord.
3. Therefore loss of tension on the vocal cord causing shortening of the vocal cord.
** Recurrent laryngeal nerve lesion**
1. Unilateral complete cut leads to paralysis of all laryngeal muscles except cricothyroid on one side.
-vocal cord assumes midway position between adduction and abduction ( cadaveric position)
- Unilateral partial crush will lead to injury of peripheral fibres which supply the abductor( posterior cricoarytenoid) . Deep fibres supply other muscles.
- vocal cord is adducted to midline - Bilateral lesion- both vocal cords adduct in midline causing severe stridor
State the arterial supply of the larynx.
1. Superior laryngeal artery- from superior thyroid artery.
- accompanies internal laryngeal
2. Inferior laryngeal artery- from inferior thyroid artery.
- accompanies recurrent laryngeal
