Anatomy and physiology of larynx presentation for MBBS 3rd year. This ppt presents the most detailed presentation of anatomy and physiology of larynx. Presenter was third year MBBS students of Nepalgunj Medical College and teaching hospital, Nepalgunj Nepal. Niraj Prasad Sah won the best presentation award for this during ENT posting. Have fun and check this out.

1. Anatomy and physiology of Larynx
ENT presentation
Group D

6. Thyroid cartilage
.This is the largest cartilage of the larynx. It has two alae,which meet
in the midline at an angle of90° in males. Due to this males have the
laryngeal prominence knownas Adam’s apple.
In females the angle is120°.
.The thyroid ala on each side on their lateral aspect, projects
superiorly and inferiorly to form superior and inferior cornu of
thyroid. The inferior cornu of thyroid articulates with the cricoid.
On the external surface of each thyroid ala runs a line obliquely from
the base of superior cornu to the midpointof inferior border. It is
known as oblique line of thyroid

10. Epiglottis
• aleaf shaped yellow elastic cartilage.
• Its upper surface near the tongue is called the lingual surface
and its lower surface facing the laryngeal cavity is known as
the laryngeal surface.
• The epiglottis is attached above to the hyoid bone by
hyoepig-lottic ligament
• and below, it is attached to the midpointof thyroid angle by
thyroepiglotic ligament.

23. • This membrane extends from both the
sides of epiglottis to the arytenoids. The
upper border of quadrangular membrane
oneach side is known as Ary-Epiglotticfold
(AE fold)
• .The lower border of quadrangular
membrane form the false vocal cord/fold
• The false vocal cords attach anteriorly to
the thyroid cartilage just below the
epiglottis and posteriorly to the arytenoids.
The false vocal cords are also known as
ventricular folds or vestibular folds.
Quadrangular ligament

25. Conus elasticus
.is a cone-shaped membrane.
.The lower border of the cricovocal membrane attachés to the
entire upper border of cricoid on each side.
• The upper border of the cricovocal membrane on each side is
free and forms the true vocal cord/ fold which attaches
anteriorly to laryngeal surface of thyroid angle
• It is attached posteriorly to the vocal process of arytenoids.
• From the upper border of cricoid the two cricovocal
membranes go medially upwards in the form of a cone (the tip
of the cone being the true vocal cords) hence known as conus
elasticus.

26. Crico-thyroid ligament
• Anterior thickening of cricovocal
membrane, connecting cricoid and
thyroid.
• The cricothyroid membrane is the site
for crico thyrotomy.
• which is an emergency procedure to
restore airway when the obstruction is
at or above the level of vocal cords.

35. ANATOMY OF LARYNX
(CONT….)
-NIRAJ PRASAD SAH
(3rd YEAR MBBS)
(GROUP ‘D’ POSTED IN DEPARTMENT OF ENT & HNS)

36.  OVERVIEW
• Cavity Of The Larynx
• Spaces Of The Larynx
• Mucous Membrane Of The Larynx
• Neurovascular Supply To The larynx
• Embryological Development
• Pediatric Vs Adult Larynx
• Normal anatomy in Xray- Neck

37. Cavity Of The Larynx
• Cavity of larynx is divided by two pairs of mucosal folds, the vestibular and vocal folds into three
major regions- Vestibule , ventricle and subglottic space.
• Laryngeal inlet: the superior aperture of the cavity which opens into the anterior aspect of
pharynx just below and posterior to the tongue.
• Laryngeal outlet: it is continuous with the lumen of trachea and is completely encircled by
cricoid cartilage. Its horizontal in position unlike inlet which is oblique.
• The Vestibule
• Ventricle (Sinus of larynx) and saccules
• Infraglottic part
• False and true vocal Cords (VC)
• Rima glottidis and Rima vestibuli

40. Spaces Of The Larynx
A. Pre-epiglottic spaces: boundary
Ant- thyroid cartilage and thyrohyoid membrane
Sup- Median thyroepiglottic ligament and vallecula
Post- anterior surface of epiglottic cartilage
Laterally continuous with paraglottic space.
B. Paraglottic space- bounded anterolaterally by inner
perichonrium of thyroid cartilage, medially by ventricle
posteriorly by reflection of pyriform fossa mucosa.
C. Reinke’s space : The superficial lamina propria,
also referred as Reinke’s space is the layer
of the VC comprised of fluid and loose elastic tissues.
- Hirano’s cover body model ( Double layer vibrator)

41. Mucous Membrane Of The Larynx
• It lines the epithelium and is loosely attached except
-posterior surface of epiglottis
-true vocal cords
-corniculate and cuneiform cartilages
Lining epithelium- ciliated columnar epithelium except over the VC and upper
part of vestibule where it is st. squamous epithelium.
Firmly
attached

42. Neurovascular Supply To The larynx
 Arterial supply:
• The major blood supply of larynx is by
:
1. Superior laryngeal artery:
 branch of Sup. Thyroid art. From ECA
2. Inferior laryngeal artery
 Branch of thyrocervical trunk from
SCA

43.  Venous drainage
• Veins draining the larynx accompany the arteries.
• They are:
1. Superior laryngeal vein :
 drains to superior thyroid vein,
 drain into the IJV
2. Inferior laryngeal vein:
 Drains into internal thyroid vein,
 drain into left BCV
 Lymphatic drainage
 Lymphatics drains regions above and below the
vocal cord .
 Above- anterosuperior group of deep cervical
nodes
 Below- posteroinferior group of deep cervical
nodes, few of them drain to prelaryngeal LN by
piercing cricothyroid membrane.
 Glottis acts as watershed area with no lymphatics
 So Ca of glottis carries best prognosis

44. NERVE SUPPLY
• Sensory and motor supply to the larynx is by two
branches of vagus nerve:- the superior laryngeal
nerve and the recurrent laryngeal nerve.
• Superior laryngeal nerve :originates from inf. Vagal
ganglia high in the neck and divides just at the level
of superior horn of hyoid bone into
a. External laryngeal nerve- cricothyroid muscle.
b. Internal laryngeal nerve- mainly sensory to
laryngeal cavity down to the levels of VC
• Recurrent laryngeal nerve: originates from vagus
nerve in thorax (left) and root of the neck (right).
 Sensory to the laryngeal cavity below the level of the
VC
 Motor to all intrinsic muscles of the larynx except
cricothyroid.

45. Embryological Development
• Larynx starts to develop as a part of respiratory system – 4th WOG- from median diverticulum of the
foregut, caudal to pharyngeal pouches called as Laryngotracheal groove.
Invaginates to form laryngotracheal diverticulum- at the end of 4th week
Tracheoesophageal folds develop which later fuses to form tracheoesophageal septum-
5th week
Divides cranial portion of foregut into dorsal (primodium for oropharynx and
esophagus) and ventral part ( laryngotrancheal tube-LT )
 Laryngeal epithelium- endoderm of cranial end of LT tube
 Epiglottis- caudal part of hypobrachial eminence
 Laryngeal cartilages – 4th and 6th pharyngeal arch
 laryngeal muscles- mesenchyme from 4th and 6th p. arch
 Hyoid bone-2nd and 3rd p. arch

46. Pediatric Vs Adult Larynx
1) Positioned higher in the neck (C1-C2) compared with adult larynx(C3-C4).
2) Thyroid cartilage in infants is flat. It overlaps the cricoid cartilage which in turn is
overlapped by hyoid bone.
3) Infants larynx in small and conical. Dimension of cricoid cartilage is smaller than the size of glottis,
making subglottis the narrowest part. However in adult, larynx is cylindrical being glottis the
narrowest part.
4) Submucosal tissues of larynx in infants are comparatively loose and easily undergo edematous
changes with trauma and inflammation leading to obstruction.
5) Laryngeal cartilages are soft and easily collapsable.
6) Shows two growth spurts. In the first 3yrs, grows in width and length, thus airways surgery during
this period is avoided. The second spurt occurs during adolescence when the thyroid angle
develops. Length increases causing change in voice during puberty called puberphonia.

47. Normal anatomy in Xray- Neck

48. With aging, the corniculate and
cuneiform cartilages, the
epiglottis, and the apices of
arytenoids are transformed into
elastic cartilage. The thyroid,
cricoid and the greater part of
the arytenoid cartilage remain
hyaline and may undergo
calcification or endochondral
ossification (or both) and
become visible radiographically.

49. REFRENCES
1. Grays Basic Anatomy, 3rd Edition 2023
2. Clinical Head And Neck Anatomy For Surgeons
3. Netter’s Head And Neck Anatomy
4. Bd Chaurasia Human Anatomy, Vol 3, 8th Edition
5. Dhingra’s Ent, 7th Edition
THANK YOU

50. PHYSIOLOGY OF LARYNX
The larynx performs the following important functions:
1. Protection of lower airways
2. Phonation
3. Respiration
4. Fixation of the chest.

51. A. PROTECTION OF LOWER AIRWAYS
Phylogenetically, protection of lower airways 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.
When food is swallowed, its entry into air passage is prevented by closure
of three successive sphincters consisting of
(i) laryngeal inlet (aryepiglottic folds, tubercle of epiglottis and arytenoids,
approximate thus closing the laryngeal inlet completely),

52. (ii) false cords and
(iii) true cords, which close the glottis.
Thus, no foreign matter meant to be swallowed or accidentally vomited
can enter the larynx.
Respiration temporarily ceases through a reflex generated by afferent
fibres of ninth nerve, when food comes in contact with posterior
pharyngeal wall or the base of tongue.
Cough is an important and powerful mechanism to dislodge and expel a
foreign particle when it comes into contact with respiratory mucosa
Larynx is aptly called watch-dog of lungs as it immediately “barks” at the
entry of any foreign intruder.

53. B. PHONATION
Larynx is like a wind instrument. Voice is produced by the following mechanism
(aerodynamic myoelastic theory of voice production):
1. Vocal cords are kept adducted.
2. Infraglottic air pressure is generated by the exhaled air from the lungs 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 lungs while pitch depends on the frequency
with which the vocal cords vibrate.

54. C. RESPIRATION
Larynx regulates flow of air into the lungs. Vocal cords abduct during
inspiration and adduct during expiration.
D. 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.