Download Larynx

The
Larynx
Interesting synonyms of Larynx
• Voice box,
• Watch dog of tracheobronchial tree
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Introduction
• The larynx is an organ that provides a protective
sphincter at the inlet of the air passages.
• It is also responsible for voice production ; beside that
it is a respiratory organ.
• It is situated below the tongue and hyoid bone
• and between the great blood vessels of the neck
• It lies at the level of the fourth, fifth, and sixth cervical
vertebrae.
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Skeleton of larynx
Skeleton of larynx
• It is made up of 9 cartilages:- 3 paired & 3
unpaired
•
Unpaired
Paired
Thyroid
Arytenoid
Cricoid
Corniculate
Epiglottis
Cuneiform
Thyroid cartilage
Shield
• The biggest cartilage & it encircles the laryngeal
lumen.
• It is made of 2 laminae of hyaline cartilages .
• They join together anteriorly (Adam’s apple).
• Diverge posteriorly.
Thyroid cartilage
Thyroid cartilage
• Each lamina has superior, inferior & posterior
borders.
• There are 2 prolongations from the superior
& inferior borders (thyroid cornu).
• The inferior cornu articulates with cricoid to
form cricothyroid joint (synovial joint).
Thyroid cartilage
• On each external surface of the lamina is an
oblique line (for attachment of Muscles).
Muscles attaching to the oblique line include
• Sternothyroid muscle (insertion)
• Thyrohyoid muscle (origin)
• Inferior constrictor muscle (origin)
Cricoid cartilage
• like signet ring .
• It is the only complete ring of cartilage in the
walls of respiratory system.
• It is made by lamina posteriorly & arch
anteriorly.
• The cricoid has two joints
The epiglottic cartilage
• leaf-shaped structure
• It lies in the upper portion
of the larynx.
• prolonged below into a
slender process (STALK or
petiole).
• attached in the midline to
the back of the laryngeal
prominence
Arytenoid Cartilages
• Each of the pair is a three-sided pyramid with
anterolateral, medial and posterior surfaces.
• The inferior base has
• 1- forward projection, (vocal process); which
provides attachment to the posterior end of
the true vocal cords.
Arytenoid Cartilages
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2- Lateral projection, the muscular process.
It provides attachment to:Posteriorly: posterior cricoarytenoid muscle
Anteriorly: lateral cricoarytenoid muscle
Arytenoid cartilages
Articulations of Arytenoid cartilages
• Cricoarytenoid Joint:• Is a synovial joint between the arytenoid
cartilage and the lateral aspect of the lamina of
the cricoid cartilage.
• Cricothyroid joint:• Is a synovial joint between the lamina of cricoid
& inferior thyroid cornu
Interior of Larynx
• The laryngeal cavity extends from the laryngeal
inlet, through which it communicates with the
• laryngopharynx, to the level of the inferior
border of the cricoid cartilage.
•
3 regions
• 1-Supraglottis: from the tip of epiglottis to
vocal cords.
• 2- Glottis ((the vocal apparatus of the larynx) :area of vocal cords.
• 3- Sub glottis:- from under surface of vocal
cords to the 1st tracheal ring
Arteries of Larynx
• They are branches of the superior and inferior
thyroid arteries.
• 1- The superior laryngeal artery;-accompanies
• the internal branch of the superior laryngeal
nerve
• 2- Inferior laryngeal artery:-accompanies the
inferior laryngeal nerve (terminal part of the
recurrent laryngeal nerve).
•
Veins of Larynx.
• 1-The superior laryngeal vein:- usually joins the
sup. thyroid vein
• 2- The inferior laryngeal vein:- usually joins the
inferior thyroid vein.
Nerves of larynx
The nerves of the larynx are the superior and inferior
laryngeal branches of the vagus nerve
1-The superior laryngeal nerve:- from inferior vagal
ganglion.
The nerve divides into two terminal branches within
the carotid sheath.
1- The internal laryngeal nerve(sensory & autonomic)
Supply the mucosa above the vocal cords
Nerves of larynx
• 1- The external laryngeal nerve:- supplies the
• 1- Cricothyroid muscle (external tensor of
vocal cords).
• 2- Inferior constrictor muscle.
Inferior (Recurrent) laryngeal n.
• It is the primary motor nerve of the larynx.
• It supplies all the intrinsic muscles except the
cricothyroid,
• It also provides sensory fibers to the mucosa
below the vocal cords.
The vocal folds
• The vocal folds are the sharp-edged folds of
mucosa overlying the vocal ligaments and they are
the source of the sounds (tone) that come from the
larynx
• Each vocal fold contains a:• 1- Vocal ligament, consisting of thickened elastic
tissue.
• 2- Vocalis muscle:-medial fibres of thyroarytenoid
muscle.