anatomy of larynx

Anatomy of Larynx

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LARYNX (voice box)

Organ Of Phonation

Air Passage

Sphincter At The Inlet Of Lower Respiratory Passage

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Epithelium – endoderm of laryngotracheal groove

Cartilage and muscles – mesenchyme of 4th & 6th pharyngeal arches

Arytenoid swelling – laryngotracheal groove – mesenchyme proliferation

Laryngeal ventricles – 10th week of gestation

Epiglottis – hypobranchial eminence

Superior laryngeal nerves – 4th pharyngeal arch

Recurrent laryngeal nerve – 6th pharyngeal arch

EMBRYOLOGY

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SITUATIONAnterior Midline Of Neck

Root Of Tongue To Trachea

Adult – C3 To C6

Higher In Children And Females

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Mal

e –

44m

m

Female – 36m

mSize

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Skeletal Framework

Ligaments Cartilages

JointsMembranes

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3 Paired &3 Unpaired

TotalThyroid , Cricoid and Epiglottis

Unpaired

Arytenoid , Corniculate and Cuneiform

Paired

Cartilages• Thyroid cartilage• Cricoid cartilage• Arytenoid cartilage (base)

Hyaline cartilage

• Epiglottis• Cuneiform cartilage• Cuneiform cartilage• Tritiate cartilage• Arytenoid cartilage (apex)

Elastic cartilage

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C3 - Body of hyoid & its

greater cornua

C3 to C4 - Upper thyroid

cartilage

C4 to C5 - Thyroid

cartilage

C6 - Cricoid cartilage

Levels

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EpiglottisLeaf shaped, curved, flat – anterior wall of upper

larynx

Upper end – free, broad

Lower end/ Petiole – long, narrow

Thryoepiglottic ligament

Aryepiglottic Folds

Tongue – medial & lateral glossoepiglottic folds

Hyoid bone – hyoepiglottic ligament

Posterior surface

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EpiglottisQuadrangular membrane runs on lateral sides of epiglottis & arytenoid cartilages on either side

Aryepiglottic fold = upper free margin Quadrangular membrane and covering mucosa

During swallowing,

• It overlies laryngeal inlet• Aryepiglottic muscle closes the inlet.

Thryoepiglottic muscle – keeps inlet patent during breathing

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Thyroid Cartilage

Largest , ‘V’ shaped

Lamina – Right and Left

Anterior border – fused• Males – 90 degrees• Females – 120

degrees

Laryngeal prominence – Adam’s apple

Thyroid notch

Posterior border – apart• Superior cornua

• Inferior cornua

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Thyroid Cartilage

Superior cornua• Thyrohyoid ligament

• Cartilago triticia

Inferior cornua:• Cricothyroid

joint Conus Elasticus

Outer surface – oblique line• Thryohyoid ,

Inferior constrictors of pharynx , Sternothyroid

Cricoid cartilage –

Cricothyroid membrane

Hyoid – Thyroid

membrane

13Signet ring shaped

Anterior part – arch

Posterior part – lamina

Lamina – arytenoids cartilage

Inferior cornua of thyroid cartilage

Junction of arch and lamina

Cricoid Cartilage

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Cricothyroid and Cricovocal

membranes

Lamina – “ Posterior

Cricoarytenoid muscle ”

Anterolateral part – Lateral

Cricoarytenoid muscle

Anterior part – Cricothyroid

muscle

Cricoid Cartilage

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Arytenoids CartilagePyramid shaped Upper border of

Cricoid lamina

Apex – Corniculate cartilage, aryepiglottic

folds

Base – Lateral part of upper Cricoid Lamina

Vocal process

Muscular process

Vocal process – Vocal fold & Vocalis muscle

Above – Vestibular

fold

Muscular process – Posterior

Cricoarytenoid, Lateral Cricoarytenoids

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Cartilage of Santorini

Small conical shaped

Apex of arytenoids

Aryepiglottic folds

Corniculate Cartilage

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Cartilage of Wrisberg

Small rod shaped

Aryepiglottic folds

Cuneiform Cartilage

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Laryngeal JointsCricothyroid Joint• B/w Inferior cornua of Thyroid

cartilage & side of Cricoid cartilage• Synovial joint• Rotatory movements• Gliding movements

Cricoarytenoid Joint• B/w base of arytenoid cartilage & upper

lamina Cricoid cartilage• Synovial joint• Rotatory movements• Gliding movements

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Extrinsic• Thryohyoid

membrane• Hyoepiglottic

ligament• Cricotracheal

ligament

Intrinsic• Quadrate membrane• Cricovocal

membrane• Cricothyroid ligament• Thryoepiglottic

ligament

Laryngeal Ligaments & Membranes

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Thry

ohyo

id m

embr

ane Connects Thyroid

cartilage to Hyoid boneMedian – Median Thyrohyoid ligament Lateral – Lateral Thyrohyoid ligamentInternal laryngeal nerve & Superior laryngeal vessels

Hyo

epig

lotti

c lig

amen

t Connects upper Epiglottic cartilage to hyoid bone

Cric

otra

chea

l lig

amen

t Connects Cricoid cartilage to upper Trachea

Extrinsic

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Intrinsic ligaments – part of Fibroelastic membrane of larynx

Intrinsic

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Inlet of larynx Anteriorly – Epiglottis Posteriorly – arytenoids cartilages Either side – aryepiglottic folds

Folds – Vestibular & Vocal folds

Rima Vestibuli

Rima Glottidis Narrowest part of larynx, longer in males

Cavity of Larynx

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Three parts•Vestibule•Ventricle•Infraglottic part

Sinus of Morgagni – cleft B/w vestibular and vocal folds

Saccule – blind conical pouch•Extends from inferior ventricle B/w vestibular fold and inner thyroid lamina

•Mucous glands – help in lubrication (Oil can of Larynx)

Cavity of Larynx

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Multi-layered , white structure

B/w Anterior commissure & anterior end of arytenoids

Arcuate lines – limit it

Layers• St. Sq. Epithelium

lined mucosa• Lamina propria

Superficial layer• Lamina propria

Intermediate layer

• Lamina propria Deep layer

• Vocalis muscle

Reinke’s Space

Anatomy of Vocal Cord

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Stratified Squamous Epithelium

Non – keratinising squamous epithelium

Pseudo stratified ciliated

columnar epithelium

Mucous membrane of Larynx

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Up to vocal folds• Superior laryngeal

artery• Superior laryngeal vein

Below vocal folds• Inferior laryngeal artery• Inferior laryngeal vein

Blood Supply

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Nerve Supply

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Upper Deep Cervical lymph nodes

Pretracheal, Paratracheal &

Lower Deep Cervical lymph nodes• Vocal cords – sub

epithelial layer – Lymphatic watershed

Lymphatic Drainage

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Pre glottic space ( Boyer’s Space )

• Reinke’s edemaReinke’s space

Para glottic space

Anatomical Spaces

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Sub glottis

Glottis

Supra glottis

Surgical subdivisions of Larynx

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“7S”

Size –

small

Shape –

funnel shaped

Softness –

laryngeal cartilage

s

Superiorly – placed

Straighter & less

oblique

Sensitivity –

greater, spasm

Subglottis – narro

w

Infant larynx

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