Larynx anatomy of larynx (1)

Dr. Padmaja Pallavi Pandey

Extend from laryngeal inlet upto lower border of cricoid cartilage.

Opposite to 3rd – 6th cervical vertibrae. Narrowest part – junction of subglottic larynx

with trachea. AP diameter- 36mm in male - 26mm in female

Specialized organ at the inlet of air passage. Protective sphincter at the air passage Regulates passage of air in inspiration and

expiration. To stop food/liquid from entering the lungs Opens & closes during swallowing, coughing &

sneezing To Bear Down

While Expelling Childbirth

While Lifting PHONATION SPEECH

Laryngeal generation of voice

Larynx

Respiratory system – outgrowth of primitive pharynx 3 weeks - Hypobrancial eminence – gives rise to furcula

-> epiglottis 3.5 weeks – laryngotracheal groove, ventral aspect of

foregut 5th week – Arytenoid masses 5-7 weeks – laryngeal lumen is obliterated 9 weeks – oval shape lumen reestablished 8-10 weeks – Formation of true and false vocal cords 12th week – ventricles Laryngeal muscles – derivatives of mesoderm of 4th and

5th arches (CN X)

Development of the larynx can be divided into prenatal and postnatal stages.

At birth, the larynx is located high in the neck between the C1 and C4 vertebrae, allowing concurrent breathing or vocalization and deglutition.

By age 2 years, the larynx descends inferiorly. By age 6 years, it reaches the adult position

between C4 and C7 vertebrae.This new position provides a greater range of phonation (because of the wider supraglottic pharynx) at the expense of losing this separation of function, i.e., deglutition and breathing.

The larynx develops from the endodermal lining and the adjacent mesenchyme of the foregut between the fourth and sixth branchial arches.

At 20 days' gestation, the foregut is first identifiable with a ventral laryngotracheal groove. It continues to deepen until its lateral edges fuse.

Trachea becomes separated from the esophagus by the tracheoesophageal septum with a persistent slit like opening into the pharynx.

This fusion occurs in the caudal-to-cranial direction, and incomplete fusion results in development of persistent communication between the larynx or trachea and the esophagus

The larynx grows rapidly during the first 3 years of life, while the arytenoids remain approximately the same size.

Beginning at age 18-24 months, the larynx descends in the neck to achieve its final position at vertebrae C4-C7 by age 6 years.

The larynx elongates as the hyoid, thyroid, and cricoid cartilages separate from each other

The cricoid cartilage continues to develop during the first decade of life, gradually changing from a funnel shape to a wider adult lumen; therefore, it is no longer the narrowest portion of the upper airway.

Child’s Larynx 1)Situated high up

against C3-C5 Vertebrae

2)Is of equal size in both male & female

Adult’s Larynx 1)Situated against C4-

C6 Vertebrae2)Length-In male,it is

44mm & in female,it is 36mm

Transverse-In male, it is 43mm & in female,it is 41mm

Anteropost-In male,it is 36mm & in female,it is 26mm.

3)Is funnel shaped (narrow subglottis)

4)Cartilages are softer5)Epiglottis is

narrower,longer, stiffer & folded with more of submucosal space

6)Proportionately smaller larynx.

7)Cricoid cartilage is the narrowest portion

3)Glottis is the narrowest part.

4)Cartilages are not softer

5)Epiglottis is broader & shorter.

6)Longer larynx.

7)Vocal folds is the narrowest portion

8)Aryepiglottic folds lies closer to the midline.

9)Vocal folds form an anterior angle with respect to perpendicular axis of Larynx.

10)Pliable laryngeal cartilage.

11)Mucosa is more vulnerable to trauma.

8)Aryepiglottic folds lies away from the midline.

Unpaired cartilagesEpiglottisThyroid cartilageCricoid

Paired cartilagesArytenoidCorniculateCuneiformAll cartilages are

hyaline except the epiglottis (elastic)

The framework of the larynx is made up of cartilages. These cartilages are connected by joints, membranes

& ligaments. Moved by muscles. Lined by mucous membranes.

The Laryngeal cartilage are Nine

3 single & 3 Paired Single:

Thyroid Cricoid Epiglottis.

Paired: Arytenoids Corniculate Cuneiform.

It is the largest of the laryngeal cartilage Shield shaped, open posteriorly, angulated anteriorly The angle between 2 laminae is 90 in male & 120 in

female Angulation more acute in males Formed of 2 laminae, each has superior & inferior

horn which fuses in midline.

Its function is to shield larynx from injury and provide an attachment to vocal cords

Encloses the larynx anteriorly and laterally

Connection of the thyroid cartilage:

Superior: To hyoid bone by thyrohyoid membrane.

Inferior: To cricoid cartilage by the cricothyroid joint & cricothyroid membrane

Signet ring shaped Hyaline. Stronger than thyroid

cartilage. Lamina-a flat portion with

2 to 3 cm from above downwards, considerably broader than anterior arch & wide posterior lamina.

Only cartilage forming complete ring

Directly below the thyroid cartilage.

Important from structural & functional point of viewBase for entire larynxSupport to arytenoidAttachment to intrinsic musclesOnly part of cartilagenous framework that

forms continuous 360 degree ringOnce injured or strictured , difficult to resect

while preserving laryngeal function.Connected superiorly to thyroid cartilage by

cricothyroid joint and cricothyroid membrane.Only complete annular support of the larynx Articulates with Inferior cornu of the thyroid

cartilage

Thin leaf shaped fibro-cartilage, situated in midline.

Lies behind the root of the tongue.

Upper free end broad & rounded, projects up behind base of tongue.

Connected by its stalk to the back of the thyroid cartilage.

Narrow base called pitiole. This attachment forms lower

limit of pre-epiglottis space.

Half of epiglottis projects above hyoid

This part has a laryngeal and lingual surfaces

Its sides are connected to the arytenoid cartilage by aryepiglottic fold

Its upper end is free. But its mucous membrane is connected to the back of tongue by 3 glossoepiglottic folds 1 median & 2 lateral

Infrahyoid portion has no free anterior surface

Forms posterior wall of PES Epiglottic cartilage

contains many pits filled with mucous glands

Little barrier between infrahyoid portion and PES

Attatched anteriorly to hyoid bone by hyoepiglottic ligament and inferiorly to thyroid cartilage by thyroepiglottic ligament

Hyoepiglottic ligament divide it into suprahyoid & infrahyoid epiglottis.

Paired hyaline cartilages, smaller in size & pyramidal in shape.

Its base sits on the superior surface of the cricoid lamina

Has 2 process:-1)Muscular process-Directed

laterally & gives attachment to 3 muscles:-

# Posterior cricoarytenoid# Lateral Cricoarytenoid# Thyroarytenoid.

2)Vocal process-Anterior angle elongated into vocal process which receives insertion of vocal ligament, which directed forward and gives attachment to the vocal ligament.

Shaped like a 3- sided pyramid Apex: directed superiorly, supports the corniculate

cartilage. Responsible for opening and closing of the larynx 2 fossa presents on anterolateral surface-upper and

lower triangular fossa.(1)Upper triangular fossa give attachment to vestibular

ligament.(2)Lower fossa to vocalis and lat.cricoarytenoid muscle Posterior surface is covered by transverse arytenoid

muscle

The arytenoid cartilages, two pyramid shaped cartilages rest on the cricoid at the cricoarytenoid joints and move in two distinct ways:

1.) To pivot (rocking) the posterior ends of the arytenoids away from each other, adducting the anterior ends or the reverse so the anterior ends abduct, and…

2.) Sliding the arytenoids on an anterior-posterior path.Since the vocal folds are attached to the anterior ends of these cartilages (at the vocal process) any movement in them will change the folds’ shape, tension and relationship to each other thereby affecting phonation.

1. Epiglottis

2. Arytenoid cartilage

3. Corniculate cartilage

4. Aryepiglottic fold

Fibroelastic Cartilages of Santorini Situated in the aryepiglottic folds Articulate with apex of arytenoid

cartilage

Firboelastic cartilages Cartilages of Wrisberg Elongated pieces of small yellow elastic

cartilage in the aryepiglottic folds

Cartilago triticea Small elastic cartilage in the lateral

thyrohyoid ligament.

SUPRAGLOTTIS GLOTTIS SUBGLOTTIS

Consists of:-1)Ventricles2)Suprahyoid epiglottis(Lingual & Laryngeal surfaces)3)False vocal cords4)Laryngeal surface of epiglottis5)Aryepiglottic folds6)Mucosal expanse7)Arytenoids8)Infrahyoid epiglottis Posterior tapering shape reduces area of mucosa in

posterior region So majority of SG tumors are epiglottic

Consists of:-1)True Vocal cords2)Anterior commissure3)Posterior commissure Narrow triangular space

between the true cords is called “rima glottis”

Anterior 2/3 is membranous Posterior third consists of

vocal processes of arytenoids Posterior 1/3 of cords and

covering mucosa are called “posterior commissure”

# Consists of a mobile upper and fixed lower part# Extends from 5-10mm below the vocal cord upto

lower inf border of cricoid cartilage.

TRUE VOCAL CORD1)Glottis contains true vocal

cord.2)Protection of lower

respiratory tract.

3)Tissue can actually regenerate, when removed.

4)Encloses vocal ligament & a major part of the Vocalis muscle.

FALSE VOCAL CORD1)Supraglottis contains

false vocal cord.2)Forms boundaries of

the Quadrangular membrane of Intrinsic ligaments.

3)Tissue is thicker.4)Also known as

VENTRICULAR FOLDS or VESTIBULAR FOLDS or VENTRICULAR BANDS.

TRUE VOCAL CORD5)Folds of mucous membrane in

the larynx,mainly the inferior pair forms True vocal cord.

6)Used in general speaking or can be heard when listening to most songs(non-metal).

7)Used most often when talking & Voice production.

8)The pitch vary from person to person. Female have high pitched true vocal cord than those of male.

9)BOUNDARIES:-

Ant:- Angle of the Thyroid cartilage.

Post:- Vocal processes of the Arytenoid cartilages

FALSE VOCAL CORD5)Folds of mucous membrane in

the larynx,mainly the superior pair forms False vocal cord.

6)Used in musical song,mostly in metal(Deep growl or screaming)or throat singing.

7)Can also used to produce a low,bass like pitch.

8)BOUNDARIES:-

Ant:- Angle of the Thyroid cartilage

Post:- Bodies of the Arytenoid Cartilages.

Mucosa of glottic and Supraglottic regions is stratified squamous epithelium.

Mucosa of ventricles and sub-glottic regions is pseudo-stratified ciliated epithelium

Supra and sub glottic regions particularly ventricles are rich in submucosal mucous or minor salivary glands while glottis is not.

2 Major groups

A)EXTRINSIC MUSCLE: ( move the whole larynx)

Elevators: Digastric,stylohyoid, mylohyoid, geniohyoid, stylopharyngeus, salpingopharyngeus & palatopharyngeus.

Depressors: Sternothyroid, sternohyoid & omohyoid.

Constrictor:Pharyngeal:

B)INTRINSIC MUSCLE( movement within larynx)

Control of laryngeal inlet Control of rima glottidisControl of length & tension of vocal cords All intrinsic muscles l ie inside the larynx All intrinsic muscles l ie inside the larynx

cricothyroid cricothyroid

SuprahyoidsSuprahyoids – Attach to points above the Hyoid (Jaw, Skull and Tongue),when they contract,they raise or elevate the Larynx.eg Swallowing

InfrahyoidsInfrahyoids – Attach to points below the Hyoid (one connects to the thyroid, however the others connect to the sternum and the scapula),when they contract they lower or depress the Larynx.

AdductorsAdductors – vocal folds are together AbductorsAbductors – vocal folds apart Tensors - Tensors - Stiffen Relaxors - Relaxors - Relax

Lateral Cricoarytenoids Cricothyroid InterarytenoidsTransverse ArytenoidsOblique ArytenoidsThyroarytenoid

Origin: Anterior part of arch of cricoid Insertion: Inferior border & inf. Horn of thyroid Causes flexion at cricothyroid joint Lengthens & tightens the vocal ligament Nerve supply: External laryngeal nerve of

superior laryngeal of vagus.

Posterior cricoarytenoids

Lateral cricoarytenoid Interarytenoid

muscles:Transverse &Oblique

Thyroarytenoid muscle Aryepiglottic muscles

Posterior Cricoarytenoids

External Thyroarytenoid – Relaxor, shortens Relaxor, shortens and adductsand adducts

Internal Thyroarytenoid – Tensor, shortens Tensor, shortens and stiffensand stiffens

Cricothyroid Muscles – Tensor, lengthens Tensor, lengthens and stiffensand stiffens

Pitch is determined by Relaxors and TensorsPitch is determined by Relaxors and Tensors

MUSCLE1)Cricothyroid2)Posterior

Cricoarytenoid3)Lateral

Cricoarytenoid4)Interarytenoideus5)Vocalis

ACTIONTensor,AdductorAbductor

Adductor

AdductorAdductor

MuscleExternal Thyroarytenoids –

inserts into the muscular process on the Arytenoids and the inserts into the muscular process on the Arytenoids and the Thyroid notch (shorten and adduct)Thyroid notch (shorten and adduct)

Internal Thyroarytenoids – inserts inserts

into the vocal process on the Arytenoids and the Thyroid Notch into the vocal process on the Arytenoids and the Thyroid Notch (shortens and stiffens), act antagonistically to the Cricothyroids(shortens and stiffens), act antagonistically to the Cricothyroids

Membrane

False Vocal Folds – Ventricular folds Laryngeal Ventricle Lamina propria (mucosal cover of the

vocalis muscle) – can vibrate independently of the

vocalis muscle

MOTORAll muscles of the larynx are supplied by the recurrent laryngeal nerve EXCEPT

Cricothyroid - supplied by external laryngeal branch of superior laryngeal nerve.

SENSORY & SECRETOMOTOR

Above Vocal Cords: Internal laryngeal Below Vocal Cords: Recurrent laryngeal

Superior Laryngeal Nerve -It leaves the vagus nerve high in the neck Internal -It provides sensation of

the glottis and supraglottis, which includes the pharynx, underside of the epiglottis and the larynx above the cords.

External -It supplies motor function to the cricothyroid muscle which tenses the vocal cords and could cause laryngopasm.

Recurrent Laryngeal Nerve -It provides sensation to the subglottic area which includes the larynx below the vocal cords and upper esophagus. It provides motor function to the intrinsic muscles of the larynx.

It branches from the vagus in the mediastinum and turns back up into the neck. On the right, it travels inferior to the subclavian and loops up, and on the left it travel inferior to the aorta and loops up.

The interior of the larynx It is divided into 3 parts: 1- vestibule: between

laryngeal inlet & vestibular fold.

2- Ventricle: a depression extending laterally between vestibular & vocal folds.

3- Infraglottic cavity: lies between the vocal fold & lower border of cricoid cartilage.

It is continuous with the trachea inferiorly.

Superior laryngeal artery – branch of superior thyroid artery

Inferior laryngeal artery – branch of inferior thyroid artery

Veins accompany the arteries

1) Pre-epiglottic space 2) Paraglottic space 3) Reinke’s space 4) Anterior subglottic wedge

Wedge shape space Boundaries:-

Superiorly: hyo-epiglottic ligament

Anteriorly: thyrohyoid memb & thyroid cartilage

Posteriorly: Infrahyoid Epiglottis

Inferiorly: Thyroepiglottic ligament Filled with fat and areolar tissue Continuous with para-glottic

space Carcinoma of laryngeal surface of

epiglottis readily spread to Pre Epiglottic Space.

Boundaries :-Laterally- thyroid cartilageMedially- conus elasticus - quadrangular membranePosteriorly- pyriform fossa

Space under epithelium of vocal cords

Mucosa over the vocal ligament loosely attached to ligaments

Thus there is a submucosal space along most of the length of true VC

Boundaries :-Above and below-arcuate linesAnteriorly– ant. Commissure Posteriorly- vocal process of

arytenoid

1)EXTRINSIC LIGAMENT:- # Thyrohyoid membrane & ligament. # Cricothyroid membrane & ligament. # Cricotracheal ligament 2)INTRINSIC LIGAMENT:- # Elastic membrane # Quadrangular membrane # Conus elasticus (cricovocal membrane+cricothyroid

membrane+vocal ligament) # Median cricothyroid ligament # Vocal Ligament # Thyroepiglottic ligament

THYROHYOID MEMBRANEpierced on each side by:1. Superior laryngeal vessels

2. Internal branch of superior laryngeal nerve

Median thyrohyoid ligament– thickened median portion

Lateral thyrohyoid ligament – thickened posterior border

- where cartilago triticea is often found

CRICOTHYROID MEMBRANE & LIGAMENTSMay be pierced for emergency tracheostomy (cricothyrotomy)

CRICOTRACHEAL LIGAMENTAttaches the cricoid cartilage to the first attached ring

ELASTIC MEMBRANE Divided into upper and lower parts by the ventricle of

the larynx lies beneath the laryngeal mucosa, Fibrous

framework of the larynx

QUADRANGULAR MEMBRANE Upper part of the elastic membrane Boundaries:- Epiglottis , arytenoid, corniculate cartilage, false cord

Forms part of wall between upper pyriform sinus and laryngeal vestibule

CONUS ELASTICUS (CRICOVOCAL MEMBRANE) Lower part of elastic membrane Composed mainly of yellow elastic tissue

BoundariesInferior: superior border of cricoid cartilage

Superoanterior: deep surface of angle thyroid cartilage

Superoposterior: vocal process of arytenoid cartilage

MEDIAN CRICOTHYROID LIGAMENT Thickened anteior partVOCAL LIGAMENT free upper edge the thread like collagenous fibers of the deep layer

of the lamina propria Interconnects the thyroid, cricoid and arytenoids

cartilagesTHYROEPIGLOTTIC LIGAMENT

Divided into 3 parts:1) Vestibule 2) Ventricle3) Subglottic spaceVESTIBULE:- Extends from laryngeal inlet to vestibular folds Boundaries:- Anterior: posterior surface of epiglottis Posterior: interval between arytenoid cartilages Lateral: inner surface of aryepiglottic folds and

upper surfaces of the false cord

VENTRICLE:- Deep eliptical space between vocal cords and

vestibular fold. Saccule – conical pouch at anterior partRima glottidis:- Elongated space between vocal cords anteriorly and

vocal processes and base of arytenoid posteriorly

CRICOTHYROID JOINT Between inferior cornu of the thyroid cartilage

and facet on the cricoid cartilage at the junction of the arch and lamina

Two movements:1) Rotation

2) Gliding

CRICOARYTENOID JOINT Base of the arytenoid cartilage and the facet on the

upper border of the lamina of the cricoid cartilage Two movements:

1) Rotation

2) Gliding

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