Download ENT10-Anat+Physl of Larynx

ANATOMY AND PHYSIOLOGY
OF LARYNX
Ranin Omar ,Shaima Alsosary and Nada
Alotaibi
-The larynx starts from the 3rd to 6th cervical
vertebrae.
-It moves vertically and in anteroposterior
direction during swallowing.
-It can also be passively moved from side to side
producing a grating sensation called laryngeal
crepitus.
Laryngeal Cartilages
3 single
3 paired
Epiglottis
It is a leaf-like. It is attached to body
of hyoid
Arytenoid
It is pyramidal in shape. It has a base
which articulates with cricoid cartilage,
and an apex which supports the
corniculate cartilage.
Thyroid
It is the largest.its anteriorly forming an
angle. Vocal cords are attached to the
middle of thyroid angle. Most of
laryngeal foreign bodies are arrested
above the vocal cords.
Cricoid
It is the only cartilage forming a
complete ring.
the posterior part is a lamina while
anteriorly it is arch.
Corniculate (Santorini)
Cuneiform (Wrisberg)
Thyroid, cricoid and most of the arytenoid cartilages are
hyaline cartilages whereas epiglottis, corniculate,
cuneiform and tip of arytenoid near the corniculate cartilage
are elastic fibrocartilage
LARYNGEAL JOINTS
Membranes & Ligaments
Extrinsic:
connect thyroid cartilage & epiglottis with hyoid bone; cricoid
cartilage with trachea.
Intrinsic:
connect cartilages of larynx to each other.
Extrinsic
Thyrohyoid
•
membrane
Hyoepiglottic
•
ligament
Cricotracheal
ligament
•
Intrinsic
1. Quadrangular membrane
 Ary-epiglottic ligament  Vestibular ligament
2. Crico-vocal membrane
 Vocal ligament  Cricothyroid membrane
3. Thyro-epiglottic ligament
Intrinsic
MUSCLES OF LARYNX
•They are of two types :
Intrinsic which attach laryngeal cartilages to each
other.
Extrinsic :which attach larynx to the surrounding
structures.
Intrinsic Muscles
A. Acting on vocal cords
Abduction   Posterior crico-arytenoideus
Adduction   Lateral crico-arytenoideus
 Transverse inter-arytenoideus
 Thyro-arytenoideus externa
Tension + lengthening   Cricothyroid
Relaxation + shortening   Vocalis
Intrinsic Muscles
B. Acting on laryngeal inlet
Opener   Thyro-epiglottic
Closer   Oblique inter-arytenoideus
 Ary-epiglottic
Extrinsic Muscles
Secondary Elevators
Primary Elevators
 Mylohyoid
 Stylopharyngeus
 Stylohyoid
 Salpingopharyngeus
 Geniohyoid
 Palatopharyngeus
 Digastric
 Thyrohyoid
Depressors
 Sternohyoid  Sternothyroid  Omohyoid
Laryngeal cavity
Rima
vestibuli
Laryngeal cavity
Extends from laryngeal inlet to
lower border of the cricoid
cartilage
Narrow in the region of the •
vestibular folds (rima vestibuli)
Narrowest in the region of the •
vocal folds (rima glottidis) •
Divided into three parts: •
Supraglottic part, the part .A
above the vestibular folds, is
called the vestibule
The part between the .B
vestibular & the vocal folds,
is called the ventricle
Infraglottic part, the part .C
below the vocal folds
Rima
glottidis
A
B
C
PHYSIOLOGY
OF LARYNX
Function of larynx :
1-protection of lower airways
2-Phonation
3-Respiration
4-Fixation of the chest
protection of lower airways :
Phylogenetically , this is the earliest function to develop ; •
voice production is secondary . The larynx protects the
lower passages in three different ways :
1-sphincteric closure of laryngeal opening
2-Cessation of respiration
3-Cough reflex
Phonation
Larynx is like a wind instrument .voice is produced by
the following mechanism :
1 vocal cords are kept adducted
2-infraglottic air pressure is generated by the exhaled
air from the lung due to contraction of thoracic and
abdominal muscles
3-The air force open the cords and is released as small
puffs which vibrate the vocal cords and produce sound
which is amplified by mouth ,pharynx, nose and chest .
this sound is converted into speech by the
modulatory action of lips,tongue,palate,pharynx and
teeth .
Intensity of sound depends on the air pressure
produced by the lung while pitch depends on the
frequency with which the vocal cords vibrate
Respiration
Larynx regulates flow of air into the lung .vocal cords •
abduct during inspiration and adduct during expiration .
Fixation of the chest
When larynx is closed , chest wall gets fixed and various •
thoracic and abdominal muscles can then act best .this
function is important in digging ,pulling and climbing .
Coughing ,vomiting ,defaecation,micturition and child birth
also require a fixed thoracic cage against a closed glottis
.
Histology of larynx
Mucosa •
False vocal cords: Pseudostratified ciliated
columnar epithelium
True vocal cords: Non Keratinized stratified
squamous epithelium
Intrinsic Muscles •
Cartilages •
- Larger Laryngeal Cartilages (Hyaline)
Lymphatic drainage of larynx
Supraglottic larynx “above vocal cord” drained into upper
deep cervical nodes
Infraglottic larynx “below vocal cords” drained into
prelaryngeal and pretracheal nodes then to lower deep
cervical and mediastinal nodes
There is no lymphatic in vocal cords
Nerve supply of larynx
Motor :
All muscles supplied by recurrent laryngeal nerve except
by external laryngeal cricothyroid muscle which supplied
n(branch of superior laryngeal n)
Sensory :
above vocal cord :internal laryngeal nerve (branch of
superior laryngeal)
Below vocal cord :recurrent laryngeal nerve
Blood supply of larynx
Arterial supply :
Laryngeal branches of superior and inferior thyroid arteries.
Venous drainage :
Superior thyroid vein> internal jugular vein
Inferior thyroid vein >brachiocephalic vien
Spaces of larynx
1-Pre-epiglottic space of boyer
2-Paraglottic space
3-reinke’s space
Embryological development
Laryngeal mucosa : endoderm of cephalic part of forgeut
Laryngeal cartilages and muscles: mesenchyme