LARYNX

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LARYNX
The larynx constitutes the organ of phonation and
forms part of the respiratory tract

• Position
• It lies in the median part of the front of the
  neck, opposite the 3rd, 4th, 5th and 6th
  cervical vertebrae.
• It extends from the upper border of epiglottis to
  the lower border of cricoid cartilage
• Its upper end opens into the laryngopharynx by
  the laryngeal inlet
• Its lower end is continuous with the trachea at
  the level of the 6th cervical vertebra.

epiglottis
C3
Hyoid bone
C6
Thyroid cartilage
Cricoid cartilage
trachea
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Structure of the larynx

• The larynx is formed of a number of cartilages
  joined together by
• Ligaments
• Membranes
• Muscles
• Synovial joints

epiglottis
Cartilago triticea
Cartilages of the larynx

• Single cartilage
• Thyroid cartilage
• Cricoid cartilage
• Epiglottis

Thyroid cartilage
Cuneiform cartilage

• Paired cartilages
• Arytenoid cartilages
• Corniculate cartilages
• Cuneiform cartilages

Corniculate cartilage
Arytenoid cartilage
Cricoid cartilage
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Thyroid cartilage

• The largest laryngeal cartilage
• Formed of 2 quadrilateral laminae which are fused
  anteriorly
• Posteriorly, the 2 laminae are separated by a
  wide gap
• The anterior border forms a median projection,
  the laryngeal prominence
• The laminae present a median V-shaped notch, the
  superior thyroid notch
• The posterior borders form upward and downward
  projections, superior inferior horns
• The outer surface of each lamina shows an oblique
  ridge, the oblique line
• The oblique line extends between two tubercles,
  the superior and inferior thyroid tubercles

Superior thyroid notch
Superior horn
Thyroid lamina
Laryngeal prominence
Oblique line
Inferior horn
Thyroid lamina
Superior horn
Superior horn
Posterior border
Superior tubercle
Laryngeal prominence
Oblique line
Thyroid lamina
Inferior horn
Inferior tubercle
Inferior horn
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Cricoid cartilage

• Smaller, but thicker than the thyroid cartilage
• Lies below and behind the thyroid cartilage
• It has the shape of a signet ring with a
  quadrilateral lamina, posteriorly, and a narrow
  arch, anteriorly
• Its lower border is horizontal
• Its upper border is sloping

Lamina of cricoid cartilage
Arch of cricoid cartilage
Upper border of cricoid cartilage
Posterior lamina of cricoid cartilage
Lower border of cricoid cartilage
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Epiglottis
Median lateral Glossoepiglottic folds

• A leaf-shaped lamella of elastic cartilage
• It projects upwards behind the tongue and hyoid
  bone
• Has an upper broad free end and a lower tapering
  end
• Anteriorly, it is connected to
• The root of the tongue, by the median and lateral
  glosso-epiglottic folds
• The hyoid bone, by the hyoepiglottic ligament
• The inner surface of the thyroid cartilage by the
  thyroepiglottic ligament

Epiglottis (posterior view)
Hyoepiglottic ligament
Epiglottis
Hyoid bone
Thyroepiglottic ligament
Thyroid cartilage
Cricoid cartilage
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Arytenoid cartilage

• A pyramid-shaped cartilage, with an apex, base
  and 3 surfaces
• Posterior surface
• Anterolateral surface
• Medial surface
• The apex is directed upwards and articulates with
  the
• corniculate cartilage
• The base is directed downwards and articulates
  with
• the upper border of the lamina of cricoid
  cartilage
• The lateral angle of the base projects to form
  the muscular process
• The anterior angle of the base projects to form
  the vocal process

Corniculate cartilage
Posterior surface
Lateral (muscular) process
Anterior (vocal) process
Lamina of cricoid cartilage
Corniculate cartilage
Anterolateral surface
Lateral (muscular) process
Corniculate cartilage
Medial surface
Anterior (vocal) process
Posterior surface
Anterior (vocal) process
Lateral (muscular) process
Cricoid cartilage
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Corniculate cartilage

• A small cartilage on the apex of the arytenoid
  cartilage
• Enclosed in the aryepiglottic fold forming the
  corniculate tubercle

Corniculate cartilage
Cuneiform cartilage A small nodule enclosed in
the aryepiglottic fold forming the cuneiform
tubercle
Aryepiglottic fold
Cuneiform tubercle
Corniculate tubercle
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Joints of the larynx

• Cricothyroid joints
• One on each side
• A synovial joint between the inferior horn of the
  thyroid cartilage and the side of the cricoid
  cartilage

• Cricoarytenoid joints
• One on each side
• A synovial joint between the base of arytenoid
  cartilage and upper border of the cricoid lamina

Arycorniculate joint

• Arycorniculate joints
• One on each side
• A joint between the apex of the arytenoid
  cartilage and the corniculate cartilage

Cricothyroid joint
Cricoarytenoid joint
Cricothyroid joint
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Membranes and ligaments of the larynx

• Thyrohyoid membrane
• Extends from the upper border of thyroid
  cartilage to the upper border of posterior
  surface of hyoid bone
• Separated from the posterior surface of hyoid
  bone by the hyoid bursa
• The median part of the membrane is thickened to
  form the median thyrohyoid ligament
• The membrane is pierced by the superior laryngeal
  vessels and the internal laryngeal nerve.
• The posterior border is thickened to form the
  lateral thyrohyoid ligament
• The lateral thyrohyoid ligament contains a
  cartilage nodule called the cartilago triticea.

Lateral thyrohyoid ligament
Cartilago triticea
Foramen for sup laryngeal vessels internal
laryngeal n.
Thyrohyoid membrane
Median thyrohoid ligament
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• Cricothyroid ligament (conus elasticus)
• An elastic band which lies below and on the inner
  aspect of the thyroid cartilage
• It is connected to
• Thyroid cartilage
• Cricoid cartilage
• Arytenoid cartilage
• Two parts of the ligament can be recognized
• Median cricothyroid ligament the anterior
  thickened part of the ligament which connects the
  adjacent borders of the cricoid and thyroid
  cartilages.
• - The ligament is overlapped by the cricothyroid
  muscle.

Median cricothyroid ligament
Median cricothyroid ligament
Cricothyroid muscle
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• Lateral cricothyroid ligament (crico-vocal
  membrane)
• this ligament is attached inferiorly to the upper
  border of cricoid cartilage
• superiorly, it has 2 attachments
• to the inner surface of thyroid cartilage,
  anteriorly
• to the vocal process of arytenoid cartilage,
  posteriorly
• The free upper border of the crico-vocal membrane
  is called the Vocal Ligament

The vocal ligament is attached to the inner
surface of thyroid cartilage (anteriorly) and to
the vocal process of the arytenoid cartilage
(posteriorly)
Thyrohyoid ligament
Thyroid cartilage
Median cricothyroid ligament
Vocal ligaments
Lateral cricothyroid ligament
Vocal process
Upper border of cricoid cartilage
Vocal ligament
Vocal process
Arytenoid cartilage
Posteroir lamina of cricoid cartilage
Cricoid cartilage
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Other ligaments of the larynx

• Hyo-epiglottic ligament connects the anterior
  surface of epiglottis to the hyoid bone
• Thyro-epiglottic ligament connects the lower end
  of the epiglottis to the inner surface of thyroid
  cartilage
• Crico-tracheal ligament connects the lower
  border of the cricoid cartilage to the first ring
  of trachea
• Ligaments of the joints

Hyo-epiglottic ligament
Epiglottis
Hyoid bone
Thyro-epiglottic ligament
Thyroid cartilage
Cricoid cartilage
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Interior of the larynx

• Inlet of the larynx
• The opening of communication between the pharynx
  and larynx
• The laryngeal inlet is directed upwards and
  backwards
• Boundaries of the inlet
• Upper border of epiglottis anteriorly
• Aryepiglottic folds on both sides
• Mucous membrane between the arytenoid cartilages
  posteriorly

Inlet of the larynx

• Aryepiglottic fold
• A fold of mucosa extending between the apex of
  arytenoid cartilage and the side of epiglottis
• It encloses the aryepiglottic muscle, cuneiform
  and corniculate cartilages

Aryepiglottic fold
Cuneiform tubercle
Aryepiglottic muscle
Corniculate tubercle
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• Vocal fold
• A fold of mucous membrane extending from the
  inner surface of thyroid cartilage to the vocal
  process of arytenoid cartilage
• The folds enclose the vocal ligaments (upper free
  border of lateral cricothyroid ligaments)
• The fissure between the 2 vocal folds is called
  rima glottidis

epiglottis
Aryepiglottic fold
Vestibular fold
Thyroid cartilage
Sinus of larynx
Medial surface of arytendoid cartilage
Cricoid cartilage

• Vestibular fold
• A fold of mucous membrane extending from the
  inner surface of thyroid cartilage to the
  anterolateral surface of arytenoid cartilage
• It encloses a fibrous band called the vestibular
  ligament

Vocal process
Vocal fold

• Sinus of the larynx
• A recess between the vestibular and vocal folds

epiglottis

• Vestibule of the larynx
• The upper part of the laryngeal cavity, between
  the inlet and the vestibular folds

• Mucosa of the larynx
• Lined by pseudostratified columnar ciliated
  epitheliuum containing goblet cells and mucous
  glands
• The vocal folds are lined by non-keratinizing
  stratified squamous epithelium without submucosa
  or blood vessels
• The vocal folds appear pearly white during
  laryngoscopy

Thyroid cartilage
Vocal ligament
Vocal process
Arytenoid cartilage
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Rima glottidis (glottis) The fissure between the
two vocal folds anteriorly (inter-membranous
part) and the two arytenoid cartilages
posteriorly (inter-cartilagenous part)
Vocal process
Intermembranous part
Rima glottidis (glottis)
Intercartilagenous part
Arytenoid cartilage
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Muscles of the larynx

• Extrinsic muscles of the larynx
• Elevators of the larynx
• Stylopharyngeus
• Palatopharyngeus
• Salpingopharyngeus
• Depressors of the larynx
• Sternothyroid
• Thyrohyoid

• Intrinsic muscles of the larynx
• Are muscles which connect the laryngeal
  cartilages together
• All are paired EXCEPT the transverse arytenoid
• They include
• Cricothyroid
• Cricoarytenoid
• Ary-epiglottic
• Arytenoid
• Thyro-arytenoid
• Thyro-epiglottic
• Vocalis

posterior
lateral
transverse
oblique
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Muscles of the larynx
Cricothyroid The only intrinsic muscle seen on
the outside of the larynx The only muscle of the
larynx supplied by the external laryngeal
nerve O outer aspect of the arch of cricoid I
inferior horn and lower border of thyroid
cartilage A a tensor of the vocal fold
(lengthens the vocal fold) N external laryngeal
nerve
Cricothyroid m. Vertical part
Action of cricothyroid Lengthening (tightening)
the vocal cords
Cricothyroid m. oblique part
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Posterior Crico-arytenoid O posterior surface
of cricoid lamina I muscular process of
arytenoid cartilage A abduction of vocal cords
Lateral Crico-arytenoid O upper border of arch
of cricoid cartilage I muscular process of
arytenoid cartilage A adduction of vocal cords
Lateral cricoarytenoid
Posterior cricoarytenoid
Cricothyroid
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Posterior cricoarytenoid
Cricoid lamina
Muscular process
Lateral cricoarytenoid
Vocal process
Cricoid arch
Cricothyroid
Thyroid cartilage
Vocal cords
Action of lateral cricoarytenoid Adduction of
vocal cords
Action of posterior cricoarytenoid Abduction of
vocal cords
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• Transverse Arytenoid
• The only single laryngeal muscle
• The muscle is attached to the posterior surfaces
  and lateral borders of both arytenoid cartilages
• A adduction of arytenoid cartilages to close the
  rima glottidis

Oblique Arytenoid O back of muscular process of
one arytenoid cartilage I apex of the opposite
arytenoid cartilage A adduction of arytenoid
cartilages to close the laryngeal inlet
Action of transverse arytenoid Adduction of
arytenoid cartilages To close the rima glottidis
Transverse arytenoid
Oblique arytenoid
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Ary-epiglottic O from the apex of arytenoid
cartilage (a continuation of the oblique
arytenoid) I side of epiglottis A adduction of
aryepiglottic folds to close the laryngeal inlet
(acts as a sphincter)
Aryepiglottic
Thyro-arytenoid O inner surface of thyroid
cartilage lateral to the cricothyroid ligament I
antero-lateral surface of arytenoid cartilage A
a relaxant of the vocal ligaments
Oblique arytenoid
Thyro-arytenoid
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Thyro-epiglottic O Extension from the upper
fibers of thyroarytenoid I side of epiglottis A
widens the laryngeal inlet
Vocalis O deep fibers of thyro-arytenoid I
vocal process of arytenoid A a relaxant of the
vocal ligaments
Thyro-epiglottic
Vocalis
Vocal ligaments
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MOVEMENT OF VOCAL CORDS

• Adduction of vocal cords
• Lateral cricoarytenoid
• Transverse arytenoid (also closes the rima
  glottidis)

• Abduction of vocal cords
• Posterior cricoarytenoid

• Closure of laryngeal inlet
• Oblique arytenoid
• Aryepiglottic

• Widening of laryngeal inlet
• Thyroepiglottic

• Tension of vocal ligaments
• Cricothyroid

• Relaxation of vocal ligaments
• Thyroarytenoid
• Vocalis

• Closure of rima glottidis
• Transverse arytenoid

Normal larynx during inspiration
Normal larynx during phonation
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• Functions of the larynx
• Respiratory function it forms part of the
  respiratory airway
• Phonation (production of sound waves)
• Raising the intra-abdominal pressure by closing
  the rima glottidis during expiration (ex. during
  labour)

• Arterial supply of the larynx
• Superior laryngeal artery from the superior
  thyroid artery
• (it pierces the thyrohoid membrane with the
  internal laryngeal nerve)
• Inferior laryngeal artery from the inferior
  thyroid artery
• (it ascends deep to the inferior pharyngeal
  constrictor with the recurrent laryngeal nerve)

• Venous drainage of the larynx
• Superior laryngeal vein drains into the superior
  thyroid vein
• Inferior laryngeal vein drains into the inferior
  thyroid vein

• Nerve supply of the larynx
• Superior laryngeal nerve (from vagus), Divides
  into
• External laryngeal supplies the cricothyroid m.
• Internal laryngeal supplies the mucous membrane
  above the level of the vocal folds
• Recurrent laryngeal nerve (from vagus), Divides
  into motor and sensory branches
• The motor branch supplies ALL intrinsic muscles
  of the larynx (except cricothyroid)
• The sensory branch supplies the mucous membrane
  below the level of the vocal folds