Larynx


Position

  • Midline
  • Antero superior neck
  • Extends from root of tongue to trachea
  • C3- C6
  • Continues from oropharynx into trachea

Relations

Anterior :  Skin, fascia, platysma, anterior jugular veins
Posterior: Laryngopharynx
Lateral:  

  • Lobes of thyroid
  • Carotid sheath

Skeleton

Anterior wall:

(+) Epiglottis
(+) thyroid and cricoids cartilages
(+) hyoid bone

Posterior wall:

(+) Cricoid and arytenoids cartilages
(+) Small cartilages: Corniculate, cuneiforms and articial

Ligaments and membranes

  • Thyrohyoid membrane
  • Lateral and median thyrohyoid ligaments
  • Cricothyroid membrane
  • Cricotracheal ligament

Muscles of larynx

Extrinsic

Intrinsic

Anterolateral
Deep muscles
  • Infrahyoid muscles
  • Suprahyoid muscles
  • Stylopharyngeus
  • Oblique arytenoideus
  • Transverse arytenoids
  • Aryepiglottic

 
  • Cricothyroid
  • Lateral cricoarytenoid
  • Thyroarytenoid
  • Thyro epiglottic
  • Vocalis

Movements  in the larynx

Movement

Muscle

Joint

Abduction of vocal fold

Posterior cricoarytenoid

Cricoarytenoid

Adduction of vocal fold

Lateral cricoarytenoid

Cricoarytenoid

Stretching of vocal fold

Cricothyroid

Cricothyroid

Shortening of vocal fold

Thyroarytenoid vocalis

Cricoarytenoid

Closure of laryngeal inlet

Transverse  and oblique arytenoids, aryepiglottic

Cricoarytenoid

Cavity of the larynx


The inlet is called laryngeal aditus
Two folds namely vestibular fold/ false vocal cord superiorly and vocal folds (true vocal cords)
Space between vestibular folds is called Rima Vestibula
Space between vocal folds is called rima glottidis

The two folds divide cavity into three parts

  • Vestibule: between aditus and vestibular folds
  • Laryngeal vestibule: between vestibular  and vocal folds
  • Infraglottic cavity, between vocal folds and beginning of trachea

Neurovascular supply of larynx

Innervation
Arteries
Veins
Lymphatics

Motor

All other muscles – Recurrent laryngeal nerve

Cricothyroid muscle- External laryngeal


Sensory

Supraglottic – internal laryngeal nerve

Infraglottic- Recurrent laryngeal nerve
  • Superior laryngeal artery- superior thyroid

  • Inferior laryngeal artery- Inferior thyroid
  • Veins correspond to arteries and drain to:

  • Internal jugular vein

  • Brachiocephalic vein
  • Prelaryngeal nodes

  • Pre tracheal

  • Paratracheal nodes

  • Deep cervical nodes

 
The Larynx and the Ear