Anatomy of larynx details with diagrams,

Anatomy of larynx

3. LARYNX
Lies in front of hypopharynx opposite the 3
rd
to 6
th
cervical vertebrae.
Below the hyoid bone and superior to the trachea in
the midline of neck.
Larynx consists of :
1-Cartilages
2-Muscles
3-Membranes & ligaments
Male Femla
e
Length 44 mm36 mm
Transverse diameter43 mm 41 mm
AP diameter 36 mm26mm

4. CARTILAGES
Unpaired
•Thyroid
•Cricoid
•Epiglottis
Paired
•Arytenoid
•Corniculate
•Cuneiform

5. CARTILAGES
Thyroid cartilage
Largest of all.
Lies against C4-C5.
Formed of Hyaline Cartilage which tends to ossify or
calcify with age .
Its two laminae meet in midline at an angle of 90°in
males & 120°in females.
The fused laminae ends in marked projection in
midline called laryngeal prominence (Adams apple)
Vocal cords attached to the middle of thyroid angle

7. CRICOID CARTILAGE
•A complete ring
•A lamina posteriorly & an arch anteriorly

9. Epiglottis
Leaf-like yellow, elastic cartilage

10. CARTILAGES
Arytenoids
Paired & pyramidal in shape
Base articulates with cricoid
Muscular process directed laterally & attached to intrinsic
laryngeal muscles
Vocal process directed anteriorly, giving attachment to vocal
cord
Apex supports corniculatecartilage

11. Corniculatecartilages (of Santorini) articulating
with the apices of arytenoid cartilages.
Cuneiform cartilages (of Wrisberg) in each
margin of the aryepiglottic fold.

12. JOINTS
Cricoarytenoidjoint
A synovial joint
Formed b/w the base of arytenoid & a facet on upper
boderof cricoid lamina
Two types of movements –rotatory & gliding
Cricothyroid joint
A synovial joint
Formed by inferior cornuaof thyroid cartilage & a
facet on cricoid cartilage

13. MUSCLES
INTRINSIC
Acting on vocal cords
Abductors: Posterior cricoarytenoid
Adductors: Lateral cricoarytenoid
transverse arytenoid
Tensors: Cricothyroid
Vocalis(internal part of thyroarytenoid)
Acting on laryngeal inlet
Openers: Thyroepiglottic
Closers: Aryepiglottic
Interarytenoid

14. MUSCLES
EXTRINSIC
They connect the larynx to other structures
Primary elevators act directly as they are attached to
thyroid cartilage
Stylopharyngeus, salpingpharyngeus,
palatopharyngeus, thyrohyoid
Secondary elevators act indirectly as they are
attached to hyoid bone
Mylohyoid, digastric, stylohyoid, geniohyoid
Depressors
Sternohyoid, sternothyroid& omohyoid

15. CAVITY OF LARYNX
Vocal folds
(true vocal cords)
two pearly white sharp bands extending from thyroid angle to
vocal processes of arytenoids.
Vestibular folds
(false vocal cords)
fold of mucous membrane containing vestibular ligament
Ventricle
(sinus of larynx)
a deep elliptical space b/w vestibular & vocal folds, also
extending a short distance above & lateral to vestibular fold
.

16. SACCULE
Diverticulum of mucous membrane.
Starts from the anterior part of the ventricle
Extends upwards b/w vestibular folds & lamina
of thyroid cartilage.
May form laryngocele.
Epithelium of mucous membrane is ciliated
columnar except over the true cords where it is
stratified squamous type

17. LYMPHATIC DRAINAGE
Above vcs–upper deep cervical L/nodes
Below vcs–prelaryngeal& pretracheal& then to
lower deep cervical L/nodes
Nerve supply
VAGUS NERVE through RLN & SLN
Motor: all muscles RLN except cricothyroid
Cricothyroid external LN
Sensory: above vcsinternal LN
Below vcsRLN

18. SPACES OF LARYNX
Pre-epiglotticspace
Anteriorly –upper part of thyroid cartilage & thyrohyoid
membrane
Posteriorly –infrhyoidepiglottis & quadrangular membrane
Above –hyoepiglotticligament
Laterally continuous with paraglotticspace
Paraglotticspace
Laterally –thyroid cartilage
Medially –ventricle & quadrangular membrane
Posteriorly –mucosa of pyriform fossa
Reinke’sspace
A potential space under the epithelium of VCs. It is bounded
above & below by arcuate lines

19. FUNCTIONS OF LARYNX
1-Protection of lower airways:
By three ways
i-sphenctericclosure of laryngeal opening by
a-laryngeal inlet b-false cords c-true cords
ii-cessation of respiration (through reflex by 9
th
nerve)
iii-cough reflex ( to expel a foreign particle)
2-Respiration

20. 3-Phonation
a-VCs kept adducted
b-Infraglotticpressure generated by exhaled air
c-The air force open the cords & is released as small puffs
which vibrate the cords & produce the sound
4-Fixation of chest
when larynx is closed, chest wall gets fixed & various
thoracic & abdominal muscles can then act best. This function
in pulling, climbing, micturition, defaecation& childbirth.