ANATOMY OF LARYNX

MODERATOR: Dr.MANAS

PRESENTER:RAVINDRA.D

INTRODUCTION

The LARYNX is an apparatus made up of cartilage, ligaments, muscles, and mucous membrane, which guards the entrance to the lower respiratory passages (trachea, bronchi, and lungs) and houses the vocal cords.

DEVELOPMENT OF LARYNX

Development of larynx occur during the 4th week of intra uterine life

The respiratory primordium appears in the floor of the foregut in the 4th week of gestational life.

The larynx 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

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

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.

Laryngeal cartilages develop from the mesenchyme of the branchial arches.

Thyroid cartilage-- from the 4th arch mesenchyme as two lateral plates meet in the midline.

Arytenoids , Corniculate , Cricoid & Tracheal cartilages-- 6th branchial arch

Epiglottis — develops from Hypobranchial eminence Intrinsic laryngeal muscles develop from the mesoderm of the 4th and

6th arches

EXTERNAL FEATURES OF LARYNX Larynx is located anterior to

the 3rd, 4th, 5th, and 6th cervical vertebrae.

Extends from the base of the tongue to the proximal portion of the trachea.

Laryngeal skeleton is suspended from the hyoid bone by the medial and lateral thyrohyoid membrane.

The lateral lobes of the thyroid gland lie anterolateral to the thyroid and cricoid cartilage.

Isthmus of the thyroid gland lies just below the cricoid cartilage and often covers the first 1 or 2 tracheal rings.

The carotid sheath and its contents lie just posterolateral to the larynx.

The recurrent laryngeal nerve ascends in the tracheoesophageal groove and enters the larynx just posterior to the cricothyroid articulation

The 3rd to 6th cervical vertebrae, prevertebral muscles, and fascia lie posterior to the larynx.

PRINCIPAL INTERNAL FEATURES OF THE LARYNX

The cavity of the larynx extends

above – from the area of the tip of the epiglottis,aryepiglottic folds, and interarytenoid folds

below — to the 1st tracheal ring

INTERNAL CAVITY OF THE LARYNX

divided into 3 spaces:

Supraglottic,

Glottic, And

Subglottic spaces

DIFFERENCES BETWEEN ADULT & INFANT LARYNX7 S1. Size- smaller in infants

2. Shape- funnel shaped in infants , cylindrical in adults

3 . Softness-laryngeal cartilages are softer in infants

4. Superiorly placed in infants

5 . Straighter and less oblique than in adults

6 . Sensitivity is greater in infants more prone to spasm

7 . Sub glottis is very narrow ,even a small swelling can lead to airway obstruction in infants

Differences between adult & infant Larynx

Average measurements of larynx

SKELITAL ANATOMY

Laryngeal frame work consists of :

Cartilages Joints Ligaments Membranes Muscles Mucous membrane + Hyoid Bone

HYOID BONE Described with the larynx

because of its anatomic association with the laryngeal apparatus.

located in front of the 3rd cervical vertebra.

serves as an attachment for the larynx via the thyrohyoid membrane and the extrinsic muscles of the larynx.

The hyoid bone is suspended from the skull base (temporal bone) via the stylohyoid ligaments

It is an U-shaped bone with Body 2 lesser horns (cornua) 2 greater horns (cornua)

ATTACHMENTS TO THE HYOID BONE 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.

Each muscle acts to depress the hyoid bone.

SURGICAL CONSIDERATIONS In tracheal resection and anastomosis, a tension-free

closure of the distal airway is essential. The larynx can be released and "dropped" from the

hyoid bone to reduce tension on the distal suture line. This is accomplished by detaching the infrahyoid

muscles from the inferior surface of the hyoid bone body and cutting the hyoid bone just lateral to the lesser cornua

This releases the central body of the hyoid and larynx. Additional relaxation can be achieved by cutting the

suspensory ligament of the superior cornu of the thyroid cartilage

This can lower the larynx to a maximum of 4.5 cm. The hyoid bone serves as a site of access to the

supraglottic larynx and pharynx.

During the excision of a thyroglossal duct cyst,

excising the entire tract along with the central body of the hyoid bone (Sistrunk procedure) reduces the recurrence rate.

CARTILAGES OF LARYNX :

3 paired 3 unpaired

Paired : Arytenoid Corniculate cunieform

Unpaired: Thyroid Cricoid Epiglottic

THYROID CARTILAGE located anterior to the 4th

and 5th cervical vertebrae.

formed by 2 laminae which fuse ventrally in the midline of the neck, forming a protuberance, the laryngeal prominence or "Adam's apple,“

The 2 laminae meet at an angle of 90° in the male and 120° in the female.

The upper limit of fusion of the two laminae forms the superior thyroid notch

Posterior border of each lamina extends upward and downward as hornlike projections,the superior and inferior cornua

The cornua are characterized further at their origins from the thyroid laminae by superior and inferior tubercles.

Both of the superior horns are anchored to the tips of the greater horns of the hyoid bone;

both inferior horns articulate with the cricoid cartilage.

On the lateral, external surface of each thyroid lamina is—ridge ,called the oblique line,

attaches to 3 muscle1. Sternothyroid,2. Thyrohyoid,and3. Thyropharyngeus (a portion of

the inferior pharyngeal constrictor).

o The thyrohyoid membrane and median thyrohyoid ligament are attached to the upper border of the thyroid cartilage.

The lateral thyrohyoid ligaments attach to the greater cornua of the thyroid cartilage.

The cricothyroid ligaments (cricothyroid membrane) attach to the inferior border of the thyroid cartilage

5 ligaments attach as one to the posterior surfaces of the thyroid laminae near the union of the laminae (angle):

The median thyroepiglottic ligament,

The 2 vestibular ligaments,And

The 2 vocal ligaments.

SURGICAL CONSIDERATIONS The thyroid cartilage is divided in the midline

to expose the endolarynx for various procedures (for example, partial laryngectomy, laryngotracheoplasty, and arytenoidectomy).

The vocalis muscle and vocal ligaments attach to the inner surface of the thyroid cartilage at the anterior commissure

On the external laryngeal surface in adult males this point is halfway between the thyroid notch and the inferior border of the thyroid cartilage. It is slightly higher in adult females.

In many laryngofissure approaches, it may be beneficial to stay below the midpoint in order to avoid dividing the anterior commissure.

CRICOID CARTILAGE Shaped like a signet ring. signet-shaped portion of the

cricoid faces posteriorly the arch is located anteriorly, The cricoid cartilage is situated at

vertebral level C6 (occasionally reaching the middle of C6), just below the thyroid cartilage

The cricoid lamina has 2 superior facets– articulate

with the arytenoid cartilages and attach to them by the posterior cricoarytenoid ligaments

2 lower lateral facets of the lamina articulate with the inferior horns of the thyroid cartilage.

The lower border of the cricoid cartilage is joined to the first tracheal ring by means of the thick cricotracheal ligament.

Arising from the arch of the cricoid cartilage anteriorly and externally are the cricothyroid muscles.

The lamina has a midline ridge for the tendinous attachment of longitudinal fibers of the esophagus.

Lateral to this ridge are the sites of origin for the bilateral posterior cricoarytenoid muscles.

SURGICAL CONSIDERATIONS

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.

Tracheotomies are usually performed at least one tracheal ring below the cricoid cartilage (2nd or 3rd tracheal ring) to avoid subglottic stenosis.

During an emergency cricothyroidotomy, the tracheostomy tube is inserted through the median cricothyroid ligament — the quickest and easiest access to the airway.

To avoid permanent laryngeal stenosis — cricothyroidotomy must be converted to a standard tracheotomy within days.

ARYTENOID CARTILAGES Almost pyramidal in shape, with 3 surfaces, a base, and an apex. Each triangle-shaped base

articulates with the cricoid cartilage by way of a diarthrodial joint.

Base has 2 processes: Anteromedially directed

vocal process – vocal ligament is attached

Short, broad, laterally projecting Muscular process – lateral and posterior cricoarytenoid muscles are attached

Arytenoid has 3 surfaces

1. Posterior surface —Transverse and oblique arytenoid muscles attach

2. Medial surface – covered with mucous-secreting laryngeal mucosa.

3. Anterolateral surface –insertion of

thyroarytenoid muscle, part of the vocalis

muscle,and the vestibular ligament. The apex of the arytenoid

cartilage supports the corniculate cartilage

SURGICAL CONSIDERATIONS

Cricoarytenoid fixation may occur from arthritis or perichondritis (intubation injury) and limit vocal fold mobility.

Cricoarytenoid subluxation during blind intubation with a lighted stylet.

Arytenoidectomy through an external or endoscopic approach may alleviate arytenoid fixation or paralysis.

submucosal arytenoidectomy which preserves an intact laryngeal mucosa

CORNICULATE CARTILAGES ( OF SANTORINI ) small fibroelastic

nodules that sit on the apices of the arytenoid cartilages.

It has little functional importance in humans

CUNEIFORM CARTILAGES (OF WRISBERG)

rod-shaped (like ancient cuneiform script).

situated in the aryepiglottic folds anterior to the corniculate cartilages, may be entirely absent.

TRITIATE CARTILAGE an occasional, minute nodule. located in the

posterior margin of the thyrohyoid membrane

EPIGLOTTIS Oblong leaf shaped Located behind the root of the

tongue and the body of the hyoid bone and in front of the laryngeal entrance (laryngeal aditus or vestibule).

It has: 2 ends— upper & Lower 2 surfaces— Anterior & Posterior 2 Lateral borders Upper end:broad lower end: narrow –“ petiolus /

stalk ” attaches to inner surface of thyroid cartilage below thyroid notch by the thyroepiglottic ligament

It attaches to the posterior body of the hyoid bone via the hyoepiglottic ligament

it lies dorsal to the thyroid cartilage and thyrohyoid membrane, guarding the laryngeal entrance.

The space between the anterior surface of the epiglottis and the thyrohyoid membrane and thyroid cartilage is called the preglottic space

The epiglottis is attached to the thyroid cartilage by the thyroepiglottic ligament.

The aryepiglottic folds and the quadrangular membranes attach to the lower part of the lateral margins of the epiglottis.

SURGICAL CONSIDERATIONS

Acute epiglottiditis, may cause airway obstruction in children.

To rule out foreign bodies, a lateral x-ray may be ordered if the general condition of the child permits.

Laryngeal visualization must be done in the operating room to avoid airway occlusion, aspiration, and cardiac arrest.

Intubation and tracheostomy are the procedures of choice

LARYNGEAL LIGAMENTS AND MEMBRANES

Membranes — Extrinsic – Thyrohyoid membrane

Crico tracheal membrane Intrinsic — Quadrangular membrane Conus elasticus Ligaments & Folds Epiglottic ligaments Aryepiglottic fold Vestibular ligament (vestibular folds or false

vocal cords) Vocal ligaments

LARYNGEAL MEMBRANES

THYROHYOID MEMBRANE provides an extensive

connection between the thyroid cartilage and the hyoid bone bilaterally and anteriorly.

Extending from the upper border and the greater horns of the hyoid bone to the superior horns of the thyroid cartilage and its laminae

Thickens anteriorly, forming the median thyrohyoid ligament

Thickened posterior margin on each side is called the lateral thyrohyoid ligament.

SURGICAL CONSIDERATIONS

The superior laryngeal neurovascular bundle may be injured by surgical approaches to the pharynx.

One must observe great care when dissecting the greater cornu of the hyoid bone and the superior horn of the thyroid cartilage during various pharyngotomy approaches

THE CRICOTRACHEAL MEMBRANE

connects the most superior tracheal cartilage with the inferior border of the cricoid cartilage

INTRINSIC MEMBRANES connect the

laryngeal cartilages with each other to regulate movement.

There are 2 intrinsic membranes :

1. Conus Elasticus and

2. Quadrangular membranes.

CONUS ELASTICUS Conus Elasticus connects the

cricoid cartilage with the thyroid and arytenoid cartilages.

composed of dense fibroconnective tissue with abundant elastic fibers.

Having 2 parts 1 .Medial cricothyroid ligament —connects the anterior part of the arch of the cricoid cartilage with the inferior border of the thyroid membrane. 2. Lateral cricothyroid membranes originate on the superior surface of the cricoid arch and rise superiorly and medially to insert on the vocal process of the arytenoid cartilages posteriorly, and to the interior median part of the thyroid cartilage anteriorly. Its free borders form the VOCAL

LIGAMENTS

QUADRANGULAR MEMBRANE Extends from the sides

of the epiglottic cartilage anteriorly to the anterolateral surface of the arytenoid cartilage and posteroinferiorly to the corniculate cartilage.

With its covering of mucous membrane forms the aryepiglottic fold superiorly and vestibular ligament inferiorly.

it forms the medial wall of the piriform recess

The paired Quadrangular Membranes connect the epiglottis with the arytenoid and thyroid cartilages.

Course posteriorly downward and attach to the corniculate cartilages and the lateral surfaces of the arytenoids.

The cuneiform cartilages are embedded within the aryepiglottic folds.

The free inferior borders of the quadrangular membranes form the ventricular ligaments, also known as the false vocal folds.

LIGAMENTS & FOLDS OF LARYNX

Epiglottic ligaments

Aryepiglottic fold

Vestibular ligament (vestibular folds or false vocal cords)

Vocal ligaments

1 . EPIGLOTTIC LIGAMENTS AND FOLDS

  Hyoepiglottic ligament

Thyroepiglottic ligament

Median glossoepiglottic ligament

Lateral glossoepiglottic or

pharyngoepiglottic fold, attached between the base

of the epiglottic cartilage and the pharyngeal wall at the root of the tongue

2 . ARYEPIGLOTTIC FOLDS

one on each side, contain the aryepiglottic

muscles. associated with the

superior border of the quadrangular membrane.

Both aryepiglottic folds constrict the entrance to the larynx and protect the respiratory pathway by not permitting food, liquids, and foreign bodies to enter the larynx and trachea.

3 . VESTIBULAR FOLDS (FALSE VOCAL CORDS)

formed by the inferior edge of the quadrangular membrane.

Attached in front to the thyroid cartilage just below the attachment of the epiglottic cartilage

Connected behind to the anterolateral surfaces of the arytenoid cartilages.

The vestibular ligaments are located just above the vocal ligaments, separated from them by bilateral ellipsoid spaces called the laryngeal ventricles.

Overlap the true vocal folds just prior to a cough or sneeze — reinforcing the resistance offered by the true vocal folds against the internal expiratory pressures.

4.VOCAL LIGAMENTS, VOCAL CORDS, AND VOCAL FOLDS

The thickened, ligamentous, upper edges of the elastic tissue of the conus are the vocal ligaments or vocal cords.

Extend from the medial extremities of the laminae of the thyroid cartilage in the midline anteriorly (forming the anterior commissure) to the apices of the vocal processes of the arytenoid cartilages on each side posteriorly.

STRUCTURE OF VOCALCORD

Histologically 5 layers: LAYER 1: is the squamous epithelial lining. It is very thin and helps to hold

the shape of the vocal fold. This layer doesnot contain any mucous glands. LAYER 2: superfical layer of the lamina propria. It is composed of loose fibers

and matrix . This layer contains only minimal elastic and collagenous fibers and offers

least resistance to vibration. The integrity of this layer is vital for proper phonatory function.

LAYER 3: intermediate layer of lamina propria. It contains a higher concentration of elastic and collagenous fibers when

compared to layer 2. This layer is thickened at the anterior and posterior ends of the vocal folds. These thickened regions are known as anterior and posterior macula flava. These structures provide protection to the vocal folds from mechanical damage.

LAYER 4 : deep layer of lamina propria. It contains a dense collection of elastic and collagenous fibers. This layer

along with the intermediate layer constitute the vocal ligament. Some of the collagenous fibers present here gets inserted into the vocalis muscle. LAYER 5: formed by the vocalis muscle. The fibers of this muscle run parallel to the direction of the vocal fold.

Vocalis muscle is infact a portion of thyro arytenoid muscle.

At the anterior most portion of the vocal fold a mass of collagenous tissue is present--known as the anterior commissure tendon

or Broyle's ligament.

This ligament gets attached to the inner area of thyroid cartilage which is devoid of perichondrium.

Lacking a submucosa and blood vessels, the vocal ligaments appear to be pearly white and shiny.

The space between the true vocal cords (the intermembranous space) is known as the rima glottidis

RIMA GLOTTIDIS

Subdivided into 2 parts,

2/5 – intercartilaginous part (respiratory glottis,or interarytenoid space), between the arytenoid cartilages and

3/5 — the intermembranous part or glottis vocalis.

SURGICAL CONSIDERATIONS

The epithelium of the true vocal cords does not have lymphatics. Therefore, metastatic disease is a rare phenomenon.

The vocal folds are devoid of lymphatics, and it infact clearly forms the watershed zone between the upper and the lower group of lymphatics.

The pathway of metastasis of glottic cancer is via the Delphian node or paratracheal nodes and finally nodes of the superior mediastinum.

LARYNGEAL MUCOSA

Is mostly of the respiratory type called ciliated columnar epithelium,

certain areas of the larynx covered with stratified squamous epithelium are-

upper area of the anterior , dorsal epiglottic surfaces, the ventral half of the aryepiglottic folds, and the vocal cords. Mucous membrane of the supraglottic larynx is a

downward continuation of the oropharyngeal mucosa.

Infraglottic region of the larynx is made of normal respiratory mucosa

Mucous glands are found at the posterior surface of the epiglottis, aryepiglottic fold, and laryngeal appendices.

LARYNGEAL SPACES

Internal laryngeal spaces :

vestibule, ventricles, o subglottic or

infraglottic spaceso External

laryngeal spaces Paraglottic space pre-epiglottic. Space

INTERNAL SPACES (LARYNGEAL CAVITY)

VESTIBULE pyramid -shaped space

extends from the laryngeal inlet or aditus to the vestibular folds (false vocal cords).

Bounded ventrally by the posteroinferior surface of the epiglottis, dorsally by the corniculate cartilages and apices of the arytenoids, and laterally by the aryepiglottic folds and the piriform recesses.

LARYNGEAL VENTRICLES sinuses (of Morgagni), are

diverticula of the interval between the false and true vocal cords.

It is lined internally by mucosa and covered externally by a very thin layer of elastic tissue and the thin thyroarytenoid muscle.

The anterior end of the ventricle may possess an additional external expansion, the laryngeal saccule,

This extends upward deep to the internal face of the thyroid cartilage.

SURGICAL CONSIDERATIONS. Enlargement of the laryngeal

saccule is often referred to as a laryngocele.

Any obstruction of the laryngeal ventricle, such as a ventricular carcinoma, may lead to the formation of a laryngocele.

A laryngocele may bulge through the aryepiglottic fold and obstruct the endolarynx

( internal laryngocele ). It may be present outside of

the thyrohyoid membrane ( external laryngocele ).

The enlargement may even be a combined internal and external laryngocele

SUBGLOTTIC (INFRAGLOTTIC) SPACE the distal part of the

laryngeal cavity. extends from the glottis

to the inferior border of the cricoid cartilage.

The subglottic space begins below the curve formed by the vocal fold to the lower end of cricoid cartilage

SURGICAL IMPORTANCE : Narrowest area in

infants , so edema obstruction & respiratory distress occur early

EXTERNAL SPACES

Supraglottic laryngeal area is subdivided into 3 laryngeal spaces

  Paired Lateral Paraglottic Spaces

One midline Pre-Epiglottic Space

PARAGLOTTIC SPACES ( TUCKER’S SPACE)

Bounded laterally by the thyroid cartilage,

inferomedially by the conus elasticus,

medially by the ventricle and the quadrangular membrane

PRE-EPIGLOTTIC SPACE ( BOAYER’S SPACE )

Bounded superiorly by the hyoepiglottic ligament, anteriorly by the thyrohyoid membrane and ligament, and Posteroinferiorly by the 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.

SURGICAL CONSIDERATIONS

Epiglottic (supraglottic) carcinoma may spread through perforations in the epiglottis into the pre-epiglottic space.

Since the pre-epiglottic space communicates laterally with the paraglottic spaces, a carcinoma is free to spread beyond the internal boundaries of the larynx.

Therefore, supraglottic laryngectomy may be contraindicated

LARYNGEAL JOINTS

2 pairs of synovial joints

Between the major cartilages of the larynx: the cricothyroid and the cricoarytenoid.

1.CRICOTHYROID JOINT

The joints between the inferior cornua of the thyroid cartilage and the sides of the cricoid cartilage are synovial

The primary movement at the joint is rotation around a transverse axis which passes transversely through both cricothyroid joints

The effect of these movements is to lengthen the vocal folds, provided the arytenoid cartilages are stabilized at the cricoarytenoid joint.

This may also increase vocal fold tension

2.CRICOARYTENOID JOINT The crico-arytenoid joints

between articular facets on the superolateral surfaces of the cricoid cartilage and the bases of the arytenoid cartilages enable the arytenoid cartilages to slide away or towards each other and to rotate so that the vocal processes pivot either towards or away from the midline. These movements abduct and adduct the vocal ligaments

3.ARYTINOCORNICULATE JOINT Synovial or cartilaginous

joints link the arytenoid and corniculate cartilages

LARYNGEAL MUSCLES

Extrinsic muscles — which move the entire larynx,

Intrinsic muscles — which move the vocal cords.

ELEVATORS OF THE PHARYNX The Suprahyoid Muscles

Digastric Stylohyoid Mylohyoid Geniohyoid

The Longitudinal Muscles of the Pharynx Stylopharyngeus Salpingopharyngeus Palatopharyngeus

DEPRESSORS OF THE PHARYNX:

The Infrahyoid Muscles Sternohyoid Sternothyroid Omohyoid

EXTRINSIC MUSCLES

INTRINSIC MUSCLES

The intrinsic muscles are: 

Cricothyroid Posterior cricoarytenoid Lateral cricoarytenoid Arytenoid with its

transverse and oblique fibers

Thyroarytenoid and its thyroepiglottic and components

MUSCLES CONTROLLING THE LARYNGEAL INLET

Oblique arytenoid Aryepiglottic muscle

MOVEMENTS OF THE VOCAL CORDS

AdductionAbduction

Folds closed (adducted) Folds open (abducted) (View from above)

Glottis (space between folds)

ADDUCTORS OF THE VOCAL CORDS

Lateral cricoarytenoid

Transverse arytenoid

ABDUCTOR OF THE VOCAL CORDS

Posterior cricoarytenoid

MUSCLE INCREASING THE LENGTH & TENSION OF THE VOCAL CORDS Cricothyroid: increases the

distance between the angle of the thyroid cartilage & the vocal processes of the arytenoid cartilages, and results in increase in the length & tension of the vocal cords

MUSCLE DECREASING THE LENGTH & TENSION OF VOCAL CORDS

Thyroarytenoid (vocalis): pulls the arytenoid cartilage forward toward the thyroid cartilage and thus shortens and relaxes the vocal cords

SPHINCTERIC FUNCTION OF THE LARYNX

There are two sphincters: At the inlet: used only

during swallowing At the rima glottis: used

in coughing and sneezing

SHAPE OF GLOTTIS

Quiet Respiration Forced Inspiration

INSPIRATION

SHAPE OF GLOTTISNormal voice

Whisper

NORMAL PHONATION

WHISPER

BLOOD SUPPLY OF LARYNX :

ARTERIAL SUPPLY Upper Larynx External carotid artery Superior thyroid artery Superior laryngeal artery

Lower Larynx Subclavian artery Thyrocervical artery Inferior thyroid artery Inferior laryngeal artery

VENOUS DRAINAGE

Upper Larynx Superior laryngeal

vein Superior thyroid vein Internal jugular vein

Lower Larynx Inferior laryngeal

vein Inferior thyroid vein subclavian vein

LYMPHATIC DRIANAGE SUPRA GLOTTIC AREA superior lymphatics drain to the upper deep cervical nodes, located at the level of the carotid bifurcation. Some drainage passes

to prelaryngeal nodes. INFRA GLOTTIC AREA drain to the pretracheal lymph nodes of the proximal trachea anteriorly paratracheal nodes laterally and then to the deep cervical and superior mediastinal nodes.

GLOTIC AREA ( VOCAL FOLDS) is relatively devoid of lymphatics.

The space deep to the thin mucosa of the true vocal cords, which is called Reanke's space, has no direct lymphatic drainage.

The spread of carcinoma is, likewise and fortunately, retarded until an invasive process involves tissue peripheral to the true vocal cord.

DELPHIAN NODE : a midline prelaryngeal lymph node, adjacent to the

thyroid gland, enlargement of which is indicative of metastasis from thyroid or laryngeal carcinoma.

SURGICAL IMPORTANCE Elective dissection of node

levels II to IV for N-0 laryngeal and hypopharyngeal carcinoma,

Bilateral selective dissection

is justified by the prevalence of bilateral metastases in midline and bilateral tumors.

The superior neurovascular bundle may be injured during anterior and lateral pharyngotomy approaches to the larynx.

Branches of the cricothyroid artery may be accidentally injured during emergency cricothyroidotomy.

Supplied by Vagus nerve: Superior laryngeal nerve1. Internal branch (sensory) –

areas above the glottis2. External branch (motor and

sensory) Motor – Cricothyroid muscle Sensory – Anterior

infraglottic larynx at level of cricothyroid membrane

Inferior (recurrent) laryngeal n.

Motor – all intrinsic laryngeal muscles of SAME side (except cricothyroid) and interarytenoid muscle of BOTH sides

Sensory – areas below the glottis

NERVE SUPPLY

BIBLIOGRAPHY

SCOTT&BROWN 6TH EDITION GRAY’S ANATOMY 40TH EDITION THE LARYNX -HUGH D. CURTIN

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