3. ANATOMY OF THE LARYNX
INTRODUCTION
Hollow tubular structure situated above the
trachea.
Extends from the laryngeal inlet to the
inferior border of the cricoid cartilage .
Opposite the third to sixth cervical vertebrae,
this level may be some what higher in
women and children than in men
After puberty the antero posterior diameter
of larynx virtually doubles in males
.
4.
5.
6.
7. Embryology
Development of laryngeal cartilage
Name of the catilage Developed from
Thyroid Ventral end of 4th arch
Arytenoids 6th arch
Corniculate 6th arch
Epiglottis Hypobrachial eminence
Cricoid &Trachea 6th brachial arch
8. The larynx is divided anatomically in to
:
supra glottis .
glottis . And
sub glottis .
By the falls and
true vocal cords.
10. The supraglottis consists of superiorly the
epiglottis and aryepiglottic folds as they sweep down to
the arytenoids. Its lower border is the ventricular bands
(false cords) which form the upper border of the glottis
.
The glottis includes the vocal cords and anterior
commissure and posterior commissure.
The sub glottis becomes the trachea at the lower
border of the cricoid .( between true v.c . and lower
border of the cricoid ) .
11. The framework of the larynx
Framework of larynx is formed by cartilages.
This cartilages are linked by ligaments and membranes
.
They move in relation to one another by the action of
two groups of muscles i.e intrinsic and extrinsic
muscles. .
Lined with a the mucosal lining is continuous above
with the pharynx
and below with that of the trachea .
12. HYOID BONE :
U-shaped bone.
Provides the upper attachment for many of the extrinsic
muscles of the laryn but is not a part of it.
Suspends the larynx in the neck .
13. Cartilaginous skeleton of larynx
9 different cartilages present in the larynx .
Unpaired cartilages:
(thyroid, cricoid , epiglottis)
Paired cartilages:
(arytenoid , corniculate ,cuneiform)
14.
15. THYROID CARTILAGE:
Thyroid cartilage:
Shield like.
Largest of the laryngeal cartilages.
Has two laminae meet in the midline inferiorly.
The angle of fusion between the laminae is about 90
degree in men and 120 degrees in women.
The fused anterior borders in men form a projection,
which can be easily palpated known as Adams apple
The laminae diverge posteriorly.
The posterior border of the laminae are prolonged as
two slender processes known as the superior and
inferior comua.
16. The Oblique Line:
The oblique line extends from the superior thryoid
tubercle to the inferior thyroid tubercle.
The oblique line gives attachment to the following
muscles:
1. Thyrohyoid muscle .
2. Sternohyoid muscle .
3. Inferior constrictor muscle .
17. Ligaments attached to the thyroid cartilage:
Thyroepiglottic ligament: elastic ligament connecting
the epiglottis to the angle of the thyroid cartilage.
Vestibular ligament: Also known as the false vocal
cord.
Vocal ligament: Also known as the true vocal cord is
responsible for the generation of voice.Is covered with
squamous epithelium unlike the Respiratory tract which
is covered by ciliated columnar epithelium, to make it
easy for vocal fold to vibrate freely over the vocalis
muscle without any restriction
18.
19.
20. CRICOID CARTILAGE
The only complete cartilage ring in the whole of the
respiratory pathway.
Shape like signet ring
It lies below the thyroid cartilage.
Composed of deep broad quadrilateral lamina and
has articular facets for arytenoid cartilage each side
upper borders and lateral for inferior cornu of the
thyroid cartilage and narrow anterior arch.
21.
22. THE ARYTENOID CARTILAGES
Small paired cartilages placed close together on the
upper and lateral borders of the cricoid lamina.
Pyramidal shaped.
Has two projections, forward and lateral projections.
The forward projection is also known as vocal proces
The vocal folds are attached to the vocal process.
The lateral processes are also known as muscular
process .
23.
24. CORNICULATE AND CUNEIFORM
CARTILAGES
The corniculate cartilages are two small conical
nodules of
elastic fibrocartilage which articulate through a
synovial joint with the apices of the arytenoid
cartilages. They are situated in the posterior part of
the aryepiglottic fold.
The cuneiform cartilages are two small elongated
flakes of fibroelastic cartilage, one in each margin
of the aryepiglottic fold.
25.
26. EPIGLOTTIS
Leaf shaped fibroelastic cartilage .
Projects upwards behind the tongue and the body of
the hyoid bone. .
The sides of the epiglottis is attached to the arytenoid
cartilages by aryepiglottic folds.
The anterior surface of the epiglottis is free and is
covered with the same mucous membrane which is of
the of pharynx.
Forms a single median glossoepiglottic fold and two
lateral glossoepiglottic folds.
Between these folds lie a depression known as the
vallecula.
.
27. This long, deeply grooved, floppy epiglottis protects the
nasotracheal air passage during sucking.
29. Ligaments and membranes of the
larynx
Extrinsic and Intrinsic ligaments .
Extrinsic ligaments: connect the laryngeal cartilages to
the hyoid bone above and trachea below.
Thyro-hyoid membrane
Cricotracheal ligament
Hyo-epiglotic ligament
30.
31.
32.
33. Laryngeal fold
Vestibular Fold(False vocal cord)
The vestibular fold is a fixed fold on each side of the
larynx, is formed by mucous membrane covering the
vestibular ligament .
Vocal Fold (Vocal Cord)
The vocal fold is a mobile fold on each side of the larynx
and is concerned with voice production. It is formed by
mucous membrane covering the vocal ligament .
34.
35. Muscles of the larynx
Muscles of the larynx are divided into two sets;
Extrinsic muscles
Intrinsic muscles
36.
37. EXTRINSIC MUSCLES
Sternothyroid muscle-depress the larynx
Omohyoid muscles –depress the larynx
Sternohyoid muscle- depress the larynx
Inferior constrictor muscles-elevate the larynx
Thyrohyoid muscles -elevate the larynx
Digastric muscles -elevate the larynx
Stylohyoid muscles -elevate the larynx
Mylohyoid muscles -elevate the larynx
38. Vocal cord regulators
Five muscles move the vocal cords;
Tensing the Vocal Cords; The Cricothyroid muscle
Relaxing the Vocal Cords; The thyroarytenoid muscle
(The Vocalis)
Adducting the Vocal Cords; Lateral Cricoarytenoid
muscle
Abducting the Vocal Cords; Posterior Cricoarytenoid
muscle
Approximates the Arytenoid cartilages; Transverse
Arytenoid muscle
39.
40. Nerves
Sensory and motor innervation of the larynx is by two
branches of the vagus nerves [CN X];
the superior laryngeal nerves
the recurrent laryngeal nerves
41.
42.
43. N.B;
The muscles are all supplied by recurrent laryngeal
nerve, except The Cricothyroids which are supplied
by the anterior branch of the superior laryngeal
nerve.
44. Blood supply
The major blood supply to the larynx is by the superior
and inferior laryngeal arteries
45. Veins
superior laryngeal veins drain into superior
thyroid veins, which in turn drain into the internal
jugular veins
inferior laryngeal veins drain into inferior
thyroid veins, which drain into the left
brachiocephalic veins.
46. lymphatics
The lymphatic of the larynx are separated by the
vocal folds into ;
Lymphatics drain regions above and below the
vocal folds;
Above the vocal folds follow the superior laryngeal
artery and terminate in deep cervical nodes
associated with the bifurcation of the common
carotid artery
below the vocal folds drain into deep nodes
associated with the inferior thyroid artery
