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‫سعد يونس سليمان‬
 To discuss the basic anatomy of the larynx
 To enumerate the main functions of the larynx
Location: C4-C6
Laryngeal Cartilages
 Paired
 Arytenoid cartilage
 Corniculate cartilage
 Cuneiform cartilage
 Unpaired:
 Thyroid cartilage
 Cricoid cartilage
 Epiglottis
Thyroid Cartilage
 Hyaline cartilage
 Largest
 Encloses the larynx
anteriorly and laterally
 Two alae
 Ossification: 20-30 years
Cricoid Cartilage  Hyaline cartilage
 Directly below the thyroid
 It is the only cartilage forming a
complete ring.
 Its posterior part is expanded to
form a lamina while anteriorly
it is narrow forming an arch.
 Ossifies after the thyroid
cartilage, first part to be
calcified being the superior
portion (which can be
mistaken for a foreign body)
 Fibroelastic cartilage
 Leaf-shaped structure
 It never ossifies
Arytenoid Cartilage
 Paired.
 Smaller in size
 Responsible for opening and closing of the larynx
Arytenoid Cartilage
 Shape: pyramidal
 Base---articulate with
cricoids cartilage.
 Muscular process--laterally giving
attachment to intrinsic
 Vocal process--anteriorly, giving
attachment to vocal cord.
 Apex---support the
corniculate cartilage.
Corniculate Cartilages
 Fibroelastic
 Small cartilages that lie over the arytenoids.
Cuneiform Cartilages
 Fibroelastic cartilages
 Elongated pieces of
small yellow elastic
cartilage in the
aryepiglottic folds
Cuneiform Cartilage
Laryngeal Joints
 Cricothyroid Joint
 Cricoarytenoid Joint
 Both are synovial joints.
 Both have two movements:
 Rotation
 Gliding
Laryngeal Muscles
1- Extrinsic Muscles
 Depressor group
 Elevator group
2- Intrinsic muscles:
All are paired except Interarytenoid muscle.
They open and close the glottis; and they are of three groups:
Abductors: posterior cricoarytenoid muscle. It opens the glottis and
it is the most important muscle of the body.
Adductors: Lateral cricoarytenoid, interarytenoid, thyroarytenoid
(external part)
Tensors: cricothyroid and vocalis (internal part of thyroarytenoid )
Laryngeal compartments
 The glottis: composed of the vocal cords
 The subglottis: from the lower border of the glottis to
the inferior border of the cricoid.
 The supraglottis: extend from the upper border of
the glottis inferiorly to the hyoid bone superiorly.
 Histology
 Lining epithelium: squamous over the vocal cords
 Mucous glands and lymphatics: rich in supraglottis, nil
in glottis and very few in subglottis.
 The mucosa of the glottis and supraglottis is firmly
bound down to the underlying tissue, but not so in
the subglottic region. Here, the laxity of tissue
allows a dangerous degree of oedema, especially in
children, where the diameter of the area is relatively
smaller than in adult.
Nerve Supply
 Supplied by Vagus nerve:
 Superior laryngeal n.
Internal branch (sensory) – areas above the glottis
External branch (motor and sensory)
Motor – Cricothyroid muscle only.
 Recurrent laryngeal n.
Motor – all intrinsic laryngeal muscles
Sensory – areas below the glottis
 All muscles of the
larynx are
innervated by the
recurrent laryngeal
nerve, except
cricothyroid muscle
which is innervated
by the external
branch of the
superior laryngeal
Blood Supply
 External carotid artery
 Subclavian artery
Venous Drainage
 Internal jugular vein
 Innominate vein
Lymphatic drainage
 Main: Deep Cervical group L.N.
 The glottic area has NO lymphatic network.
Paediatric larynx
1. It is positioned high in the neck opposite C3 or C4 (level
of vocal cord) at rest and reaches C1 or C2 during
2. The laryngeal cartilage are soft and collapse easily.
3. The thyroid cartilage in an infant is flat and the
cricothyroid and thyrohyoid spaces are narrow.
4. It is small and conical in shape ( while it is cylindrical
in adult).
5. Submucosal tissues of infant's larynx are loose and
easily undergo oedematous changes with trauma or
inflammation leading to obstruction.
Function of the larynx
1- Protection
a. sphincteric closure
b. cough reflex
2- Respiration
3- Phonation
4- Fixation of chest
When the larynx is closed, chest wall gets fixed and various
thoracic and abdominal muscles can then act best-->
a-powerful voluntary muscular use of the arms.
b-fixes the diaphragm to assist in the act of straining.
Thank You