The document summarizes key aspects of larynx anatomy. It discusses: 1) The larynx functions to protect the lower respiratory tract, provide a controlled airway, and enable phonation, coughing, and lifting. 2) It consists of cartilages including the thyroid, cricoid, epiglottis, and arytenoid cartilages joined by membranes and ligaments. 3) Intrinsic muscles control the laryngeal inlet and vocal cord movements to modulate phonation, respiration, and protection of the airway.

1. Dr. Ankit Choudhary

2. Introduction
Larynx is also known as Voice box
Primary function is protection of Lower Respiratory
tract.
Provides a controlled airway.
Function in Phonation.
High Intrathorasic Pressure generation for coughing
and lifting.

3. Specifications
Male Female
Vertical 44 mm 36 mm
Transverse 43 mm 41 mm
Anteroposterior 36 mm 26 mm
Opposite C3-C6 Vertebrae
Cylindrical Tube like

4. Adult V/S Pediatrics Larynx
7 S
1. Superiorly placed in Infants (C1 to C4)
2. Smaller in Size in Infants
3. Shape-Funnel shaped (Cylindrical in adults)
4. Softness- Laryngeal Cartilage are softer in Infants
5. Straighter and less oblique in Infants
6. Sensitivity is more in Infants(More prone to spasm)
7. Sub Glottis is very narrow, even a small swelling leads
to obstruction

5. Embryology
 Development of larynx occur during the 4th week of intra
uterine life
 It begins as a slit like diverticulum (laryngotracheal groove)
in the ventral wall of the primitive pharynx
 The groove gradually deepens and its edges fuse to form a
septum, this septum separates the laryngotracheal tube
from the pharynx and oesophagus. The process of this
fusion starts caudally and extend cranially.
 Laryngeal cartilages develop from the mesenchyme of the
branchial arches.
 Thyroid cartilage develops from the 4th arch mesenchyme
as two lateral plates meet in the midline.

6. •Between 5th & 6th weeks — 3 swellings appear at the laryngeal
aditus. An anterior swelling, a derivative of the hypobranchial
eminence from 4th arch—forms Epiglottis. 2 lateral arytenoid
swellings appear, derived from the 6th branchial arch, move
medially and form a T-shaped aperture.
•Cricoid Cartilage & cartilage of trachea develops in 6th week
from 6th arch mesenchyme
•Laryngeal lumen— temporarily occluded at 8 weeks
gestational age as a result of epithelial proliferation.
•By the 10th week of gestation, recanalization occurs and
consequently pair of laryngeal ventricles are formed.
•The laryngeal ventricles are bound by mesenchyme tissue that
condense and progress into false and true vocal cords.
•Intrinsic laryngeal muscles develop from the mesoderm of the
4th and 6th arches

7. Hyoid Bone
 Hyoid bone described with the larynx because of its
anatomic association with the laryngeal apparatus.
 U-shaped bone with body, 2 lesser horns (cornua), 2
greater horns (cornua)
 Lies in front of the 3rd cervical vertebra.
 Attaches with the larynx via the thyrohyoid membrane and
the extrinsic muscles of the larynx.
 Suspended from the skull base (temporal bone) via the
stylohyoid ligaments.

8. Attachments
•Medial end of the middle constrictor muscle and the stylohyoid
ligament attach to the lesser cornu.
•The middle constrictor and hyoglossus muscles attach to the greater
cornu.
•Geniohyoid and genioglossus attaches to the inner and upper surfaces
of the body of the hyoid bone.
•The mylohyoid attaches to the anterior surface of the hyoid.
•The tendon of the digastric muscle attaches to the anterolateral
portion of the body.
•Sternohyoid, omohyoid, and thyrohyoid attaches to the inferior
surface of body.
Surgical consideration
•The larynx can be released and "dropped" from the hyoid bone to
reduce tension on the distal suture line in tracheal resection and
anastomosis
•During the excision of a thyroglossal duct cyst excision entire tract
along with the central body of the hyoid bone (sistrunk procedure)
•Access to the supraglottic larynx and pharynx.

9. The Larynx Consists of
 Cartilaginous framework
 Membranes & Ligaments
 Muscles
 Mucosal Lining

10. The Cartilages
Cartilagenous skeleton comprises of:
Unpaired Cartilage – Thyroid
Cricoid
Epiglottis
Paired Cartilage – Arytenoid
Corniculate
Cuneiform
Tritiate cartilages
The thyroid, cricoid, and most of the arytenoid
cartilages consist of hyaline cartilage, and may
therefore become calcified.
Rest all are Fibroelastic Cartilage.

11. Thyroid Cartilage
Has two laminae, which meet in the midline and
form a prominent angle, called laryngeal
prominence (Adams apple). The angle of fusion
is about 90° in men and 120° in women.
•The posterior border of each lamina forms
superior & inferior cornu (horns)
•Ossifies at 20-30 years of age, begins in the
inferior margin and progress cranially
Attachments:
 Superior border- Thyrohyoid membrane
Oblique line - Thyrohyoid, Sternothyroid &
Inferior constrictor of the pharynx
Inferior border- Cricothyroid membrane
Inner aspect- Just below the thyroid notch in
the midline is attached the thyroepiglottic
ligament and below this and on each side of the
midline, the vestibular and vocal ligaments and
thyroarytenoid, thyroepiglottic and vocalis
muscles are attached.

12. Cricoid Cartilage
•Has a narrow anterior arch & a broad posterior
lamina
•Forms a complete ring.
Attachments:
oFacet for articulation with the inferior cornu of
the thyroid cartilage near the junction of the arch
and lamina
o Lamina has sloping shoulders on which
the articular facets for the arytenoids are found

13. Epiglottis
 Thin, leaf-like sheet of elastic fibrocartilage.
 Projects upwards behind the tongue and
the body of the hyoid bone
Attachments:
 Inferiorly to the thyroid cartilage by the
thyroepiglottic ligament.
 Anteriorly to the hyoid bone by the
hyoepiglottic ligament.
 Laterally gives to aryepiglottic fold.
 Anteriorly mucosa is reflected onto the
tongue forming three glossoepiglottic folds
& valleculae
 Upper edge is free.

14. Arytenoids
•Small, irregular, three-sided pyramids
•Base articulating with the upper border
of the cricoid cartilage
•Apex supporting the corniculate
cartilage
•A vocal process projecting forward,
gives attachment to the vocal ligament
•A muscular process projecting laterally,
gives attachment to muscles

15. Corniculate cartilages
•Small nodules
•Articulate with the apices of arytenoid cartilages
Cuneiform cartilages
•Small rod shaped
•Placed in each aryepiglottic fold, producing a
small elevation
•Do not articulate with any other cartilage
• serve as support for the ary-epiglottic fold
Tritiate cartilages (Cartilago Triticea)
•Small nodules
•Situated within the posterior free edge of the
thyrohyoid membrane on either side

16. SURGICAL CONSIDERATIONS
 The thyroid cartilage is divided in the midline to expose the endolarynx for
various procedures (partial laryngectomy, laryngotracheoplasty, and
arytenoidectomy).
 During an emergency cricothyroidotomy, the tracheostomy tube is inserted
through the median cricothyroid ligament —the quickest and easiest
access to the airway.
 Injury to the cricoid cartilage from intubation or trauma may result in
perichondritis and lead to subglottic stenosis
 Surgical approaches to repair long-standing subglottic stenosis involve the
expansion of the circumference of the cricoid ring with autologous
cartilage grafts
 Arytenoidectomy through an external or endoscopic approach may
alleviate arytenoid fixation or paralysis
 Cricoarytenoid subluxation during blind intubation with a lighted stylet.
 Acute epiglottiditis, may cause airway obstruction in children.

17. Membranes & Ligaments
Extrinsic membranes & ligaments
 Thyrohoid membrane, median &
lateral thyrohoid ligaments
 Cricotracheal membrane
 Hyoepiglottic ligament
 Thyroepiglottic ligament

18. Intrinsic membrane
Quadrangular membrane:
•Extends between the epiglottis and the
arytenoid cartilages
•The upper margin forms the
aryepiglottic fold and the lower margin is
thickened to form the vestibular ligament
underlying the vestibular fold (false
cord).
Cricothyroid membrane(Conus
elasticus or Cricovocal membrane):
•Lower margin is attached to upper
border of cricoid cartilage
•Upper free margin forms vocal ligament
that is attached anteriorly to deep surface
of thyroid cartilage & posteriorly to the
vocal process of arytenoid cartilage

19. Muscles
Extrinsic muscles
• which move the entire larynx.
 Divided into two groups-
Elevators: Suprahyoid
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus
Thyrohyoid (Infrahyoid)
Depressors :Infrahyoid
Sternohyoid
Sternothyroid
Omohyoid

20. Intrinsic Muscles
 Divided into two groups
• Muscles controlling the laryngeal inlet
• Muscles controlling the movements of the vocal cords
 Muscles Controlling the Laryngeal Inlet
 Aryepiglottic muscle
 Oblique arytenoid

21. Muscles controlling the movements of the vocal cords
• Control the tension of the vocal folds
o Thyroarytenoid or Vocalis
o Cricothyroid
• Open and close the glottis
o Posterior cricoarytenoid (ABDUCTOR)
o Lateral cricoarytenoid
o Transverse arytenoids – unpaired
o Oblique arytenoids - paired

22. Cricothyroid Muscle
Posterior cricoarytenoid
(ABDUCTOR)

23. Lateral cricoarytenoid
Transverse arytenoids
Thyroarytenoid

24. Mucous Membrane
 Stratified squamous epithelium: Over Vocal cords and
upper part of vestibule of larynx
 Ciliated columnar epithelium: Remainder of the cavity
 Mucous glands:
 Ventricles and sacculi
 Posterior surface of epiglottis
 Margins of aryepiglottic folds
 Reinke’s layer of connective tissue: No glands and no lymph
vessels

25. Laryngeal Inlet
 Faces backward and upward and opens into the laryngeal
part of the pharynx
 The opening is bounded:
• Anteriorly: by the upper margin of epiglottis
• Posteriorly & below by arytenoid cartilages
• Laterally by aryepiglottic folds
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 above the vestibular folds, is called the
vestibule
The part between the vestibular & the vocal folds, is called the
ventricle
Infraglottic part, the part below the vocal folds

27. •Vestibular Part:
Extends from the inlet to the vestibular fold
Below it becomes narrow as the vestibular folds project
medially.
Each vestibular fold contains vestibular ligament, the lower
free margin of the quadrangular membrane stretching from
thyroid cartilage to the arytenoid cartilage
•Subglottic Part:
Extends from vocal folds to lower border of cricoid cartilage
Walls formed by the inner surface of the cricothyroid
ligament and the cricoid cartilage
•Glottic Part:
Extend from vestibular folds to the vocal folds
Laterally a small recess between the vestibular fold & the
vocal fold is called the sinus of the larynx, which may
extend upwards between vestibular fold and the thyroid
cartilage as saccule of the larynx

28. Vocal Fold
Layers-
1)Squamous epithelium
2)Lamina propria
A. Superficial Fibrous Reinke’s
space
B. Intermediate elastic fibre
C. Deep collagen fibres
Elastic & collagen fibres make vocal
ligament
3)Vocalis muscle
•Ant commissure-1 to 2 mm strip of columnar epithelium
Between narrowest part of vocal cord (1 mm)
Early spread of tumour to Subglottic & prelaryngeal space.
•Post commissure-ant surface of arytenoid, vocal process
•Ant subglottic wedge-Ant commissure tumours spread here

29. PRE-EPIGLOTTIC SPACE (BOAYER’S
SPACE)
Superiorly- Hyoepiglottic ligament
Anteriorly- Thyrohyoid membrane and
ligament
Posteroinferiorly- Epiglottis and
thyroepiglottic ligament.
The pre-epiglottic space forms an inverted
pyramid.
Continuous with the superior portion of the
paraglottic space. Contains abundant fat,
blood vessels, lymphatics,and mucosal
glands
PARAGLOTTIC SPACES (TUCKER’S
SPACE)
Laterally-Thyroid cartilage
Medially- Ventricle and the quadrangular
membrane Inferomedially- Conus elasticus

30. Nerve Supply
 Supplied by Vagus nerve:
 Superior laryngeal nerve.
 Internal branch (sensory) – areas above the glottis
 External branch (motor and sensory)
Motor – Cricothyroid muscle
Sensory – Anterior infraglottic larynx at level of
cricothyroid membrane
 Inferior (recurrent) laryngeal nerve.
 Motor – all intrinsic laryngeal muscles of SAME side
(except cricothyroid) and interarytenoid muscle of
BOTH sides
 Sensory – areas below the glottis

31. Blood Supply
 Arteries:
 Upper half: Superior laryngeal
artery, branch of superior thyroid
artery
 Lower half: Inferior laryngeal
artery, branch of inferior thyroid
artery
 Veins:
Accompany the corresponding arteries
 Sup laryngeal vein-Superior thyroid
vein-> Facial vein-> Internal
Jugular vein
 Inf laryngeal vein-> Inferior thyroid
vein-> Brachiocephalic vein

32. Lymphatic Drainage
Main: Deep Cervical group of L.N.
Supraglottic area
•98%: Anterior pedicle> End of aryepiglottic fold -> pass laterally and
leave the larynx through the thyrohyoid membrane ->Upper deep
cervical nodes (between Digastric tendon and omohyoid muscle)
•2%: Lower cervical chain or spinal accessory chain
Infraglottic area – 3 pedicles
• Anterior pedicle -> cricothyroid membrane -> prelaryngeal
(Delphian) nodes ->deep inferior cervical nodes
•2 Posterolateral pedicles -> cricotracheal membrane -> paratracheal
chain/others to inferior jugular chain
Vocal fold –Water shed line because poverty of lymph drainage here.

33. Endoscopic View of Larynx

34. Thank You