Anatomy of the larynxLarynx is situated in the

midline of the neck.From 3rd to 6th cervical

vertebrae.Consists of a framework of

cartilages, connected by ligaments and membranes,lined by a mucous membrane and moved by muscles.

Laryngeal cartilages Unpaired

1. Thyroid 2. Cricoid3. epiglottis

Paired

1. Arytenoid2. Corniculate3. Cuneiform

Thyroid cartilageThe largest, each half consists of Ala (lamina)

A square plate;Begin to ossify at

25;May be

completely converted to bone at 65.

Thyroid cartilageThe 2 ala meet in the

midline;Forming an angle of - 90 in men; -120 in women.Forming V shape notch

called a thyroid notch or Adam’s apple.

Thyroid cartilageAn oblique line is running downward and

foreward on the surface of each lamina,It is the site of muscular attachment.

Cricoid cartilageResembles a

signet ring, narrow in front and broad behind.

Ossification begins at 30 and may be complete by 65.

Consists of lamina and arch.

Cartilage of epiglottisRises up behind

the tongue. It is a thin leaf-

like sheet of elastic fibrocartilage.

The stem is long and thin and attached to the posterior surface of thyroid alae at their junction.

The free upper border is broad and rounded.

Cartilage of epiglottisAnterior

surface: Free in upper

part. In its lower part

is separated from hyoid bone and thyrohyoid membrane by fatty tissue

(pre-epiglottic space)

Cartilage of epiglottisPosterior surface:Is indented by several small

pits, in which mucous glands are embeded.

The tubercle of The tubercle of epiglottis projects epiglottis projects backwards in its backwards in its lower part.lower part.

Arytenoid cartilagesPyramidal in

shape;

Posterior surface is triangular and concave, it extend laterally into a muscular process.

Arytenoid cartilagesAnterolateral surf. is convex, it extends

foreward into a vocal process.

Corniculate cartilages(The cartilages of Santorini)They articulate with the apices of the

arytenoid cartilages and prolong them backwards and medially.

They give attachments to the upper fibers of the oesophagus.

Cuneiform cartilages(The cartilages of Wrisberg)

Are small bars of yellow elastic cartilage.

There is one in each ary-epiglottic fold, where it acts as a passive prop.

They do not articulate with any other cartilage.

Laryngeal joints1. Crico-thyroid joint.2. Crico-arytenoid joint.

Laryngeal ligaments and membranesIntrinsic :Uniting the cartilages of the larynx to one

another.

Extrinsic :Uniting the cartilages of the larynx to the

skeletal structures outside the larynx.

Intrinsic laryngeal ligaments and membranes

1. The elastic membrane of the larynx.

2. Thyroepiglottic ligament.

The elastic membrane of the larynx.

It is the fibrous framework of the larynx.It lies beneath the laryngeal mucosa.It is divided into upper & lower part by the

ventricle of the larynx

The elastic membrane of the larynx.

- Contribute to the support of the

aryepiglottic and ventricular folds.

-The ventricular ligament is a thickening of the free border.

The upper part(Quadrangular mem.)The upper part(Quadrangular mem.)

The elastic membrane of the larynx.

The lower part (conus elasticus or cricovocal mem.)

Inferiorly Inferiorly it is attached to the it is attached to the superior border of superior border of the cricoid cartilage.the cricoid cartilage.

Conus elasticusSuperiorly it is

attached:Infront to the

deep surface of the angle of the thyroid cartilage. The median cricothyroid ligament is formed by the thickened anterior part of the conus.

Conus elasticus

Behind attached to the vocal process of the arytenoid cartilage.

Conus elasticusThe vocal ligament is the free upper edge of

the conus between these points of attachments.

Intrinsic laryngeal ligaments and membranes2. Thyroepiglottic lig.

.

Attaches the Attaches the epiglottis to the epiglottis to the thyroid cartilagethyroid cartilage

Extrinsic laryngeal ligaments and membranesThyrohoid membrane

It is a broad sheet of fibro-elastic tissue attaches the upper border of thyroid cartilage and hyoid bone.

Thyrohoid membraneThe subhyoid bursa separates the

membrane from the posterior surface of the body of hyoid bone.

Upward movement of the larynx during deglutition is facilitated by the bursa.

The membrane is pierced on each side by: - superior laryngeal vessels. - internal branch of superior laryngeal

nerve.

Extrinsic laryngeal ligaments and membranes

Median thyrohyoid ligament.

Lateral thyrohyoid ligament.

Cricotracheal membrane.

Hyo-epiglottic ligament.

Intrinsic laryngeal muscles

1. Abductors of the vocal cords.2. Adductors of the vocal cords.3. Tensors of the vocal cords.4. Openers of laryngeal inlets.

Abductors of the vocal cordsPosterior crico-arytenoid musclePosterior crico-arytenoid muscle

Posterior crico-arytenoid musclePosterior crico-arytenoid muscle

Adductors of the vocal cords Are 3 on each side:1. Lateral crico-arytenoid muscle.2. Transverse portion of interarytenoid muscle.3. External portion of thyro-arytenoid muscle.

Lateral crico-arytenoid muscle

Lateral crico-arytenoid muscleLateral crico-arytenoid muscle

Transverse portion of interarytenoid muscle

Action of transverse portion of interarytenoid muscleAction of transverse portion of interarytenoid muscle

External portion of thyro-arytenoid muscle

Thyro-arytenoid muscleThyro-arytenoid muscle

Tensors of the vocal cords1. Cricothyroid muscle ( external tensor).2. Internal portion of thyro-arytenoid (vocalis

muscle).

Cricothyroid muscle (external tensor)

Action of cricothyroid muscle

Internal portion of thyro-arytenoid (vocalis muscle)

Openers of the laryngeal inlet

Thyro-epiglottic muscle

Closers of the laryngeal inletOblique portion of interarytenoid

muscle.

Closers of the laryngeal inletAryepiglottic muscle

Extrinsic muscles of the larynx Between the larynx and neighbouring

structures; are 2 main groups:

1. Strap muscles. (sternothyroid & thyrohyoid).2. Pharyngeal muscles.

Strap muscles

Cavity of the larynx

2 folds

1. False vocal cord.2. True vocal cord.

3 parts

1. Vestibule.2. Ventricle.3. Subglottic space

Extends from the inlet of the larynx to the lower border of the cricoid cartilage, it is divided into 3 parts by 2 folds of mucous membrane:

Vestibule.Vestibule.

Ventricle.Ventricle.

Subglottic spaceSubglottic space

False vocal cordThese are the ventricular bands which are

formed by the mucous membrane covering the ventricular ligament and the upper part of the external portion of the thyroarytenoid muscle.

True vocal cords Project further into than the false cords, and

lie at a lower level. The covering epithelium is closely bound

down to the underlying vocal ligament.The blood supply is poor, hence the pearly

white appearance of the vocal cords.

Vestibule

Bounderies:Posterior surface of epiglottis in front.Interval between the arytenoid cartilages

behind.Inner surface of the aryepiglottic folds

and upper surfaces of the false cords on each side.

Lies between the laryngeal inlet and the edges of the false Lies between the laryngeal inlet and the edges of the false cords.cords.

Ventricle of the larynx A recess between the true and false cords. It is lines by mucous membrane which is

covered externally by the thyroarytenoid muscle.

Compsed of 2 parts1. Saccule.2. Rimaglottidis.

SacculeThe saccule is a conical pouch which ascends

from the anterior part of the ventricleIt lies between the inner surface of thyroid

cartilage and the false cords.Numerous mucous glands open onto the

surface of its lining mucosa.

Vestibule.Vestibule.

Ventricle.Ventricle.

Subglottic spaceSubglottic space

Large laryngeal saccule

Rima glottidis The glottis (rima glottidis) is the interval

between:1. The true vocal cord in its anterior 3/5.2. The vocal processes of the arytenoid

cartilages in its posterior 2/5. Its average length: In the adult male is about 2.5 cm. In the adult female is about 1.6 cm.

Subglottic space

Lies between the true vocal cord and the lower border of the cricoid cartilage.

Blood supply of the larynx1. Laryngeal branches of the superior thyroid

artery.2. Laryngeal branches of the inferior thyroid

artery. 3. Cricothryoid branches of superior thyroid

artery (cross the midline at the upper part of the cricothyroid membrane).

Blood supply of the larynx

Inferior thyroid artery

superior thyroid artery

Nerve supply of the larynx

supplied by branches of vagus

Superior laryngeal nerve, has 2 branches:

1. Internal.2. External.

Recurrent (Inferior) laryngeal nerve :

1. Anterolateral (motor)2. Posteromedial(sensory

)

Superior laryngeal nerveExternal branch

Travel down on the inferior constrictor muscle of the pharynx.

Supplies the cricothyroid muscle and part of the anterior subglottis.

Suprior laryngeal nerve Internal branch -Entirely sensoy. - Pierces the

thyrohyoid membrane with the superior laryngeal artery and vein.

-Supplies the cavity of the larynx as far down as the level of the vocal cords.

Recurrent (Inferior) laryngeal nerve

longer coarse on the left.

In the left it turns round the arch of the aorta.

On the right it turns round the subclavian artery.

In the neck it lies between the trachea and the oesophagus

Recurrent (Inferior) laryngeal nerve

Its terminal part passes upward, under cover of the ala of the thyroid cartilage immediately behind the inferior cricothyroid joint, it then divided into:

1. Anterolateral (motor) branch which supplies all the intrisic muscles of the larynx except cricothyroid muscle.

2. Postromedial (sensory) branch which supplies the cavity of the larynx below the level of the vocal cords.

Lymphatic drainage of the larynx Vocal cord has no lymphatic vessels. The edges of the vocal cord divide the lymphatic

of the larynx into 2 parts:

1. Supraglottic drain into:

2. Subglottic drain into:

Pre-epiglottic nodes. Upper deep cervical nodes.

•Prelaryngeal and pretracheal nodes.

•Lower deep cervical.

Lymphatic drainage of the larynxLymphatic drainage of the larynx

Physiology of the larynx

1. Protection of the lower air passages: This is the most important function of the larynx and the earliest one to develop phylogenetically, several mechaniusms involved including closure of the laryngeal inlets of epiglottic sphincters, aryepiglottic and glottic sphincter during the act of swallowing to protect the lower air passages and direct the food smoothly into the pyriform fossa. Automatic cessation of the respiration by the efferent pathway of the CN IX is another mechanism of protection in addition to cough reflex. This is also initiated in the trachea and bronchi.

2. Respiration: Larynx is part of the upper airway passages where it plays a role in adjustment of glottic aperture by inspiratory abduction expiratory adduction contributing to the regulation of the acid-base balance in the blood by influencing CO2 tension.

3. Phonation: This is the last to develop phylogenetically, voice produced by the vibration of the vocal cord changed into meaningful speech and amplified selectively by resonating chamber of the mouth, pharynx, nose, and chest. The voice has the character of:

a)volume (intensity) which depends on the air pressure generated in the lungs by the contraction of the abdominal and thoracic muscles.

b)Pitch which determines the timper (quality of the voice) by cutting the air column generated in the lungs into puffs by vibration of the fully adducted vocal cords and the frequency of these puffs determines the pitch.

4. Fixation of the chest: When the larynx is closed voluntarily the thoracic cage becomes fixed permitting climbing, digging, and during the acts of defecation and parturition by pushing the diaphragm downward and increasing the intra abdominal pressure.

5. Sphencteric action: Occurs at three levels, aryepiglottic, false vocal cord, true vocal cord, in a sequence from below upward during the act of swallowing to protect the air passage.

Symptoms of laryngeal diseaseGenerally the laryngeal diseases are characterized by:1. Hoarseness of the voice which means rough voice, maybe a

manifestation of any laryngeal disease whether congenital, traumatic, inflammatory, or neoplastic, or as a systemic disease as hypothyroidism , lung cancer.

2. Stridor: this is produced by the turbulence of diminished air flow at the nearly completely or partially obstructed larynx in the form of musical sounds, it’s usually inspiratory at the supraglottic and glottic and by phasic in the subglottic down to the carrina, expiratory stridor (wheez) at the lower air passages.

3. Aspiration: inhalation of the food or saliva due to failure of the protective sphencteric function of the larynx manifested as chocking or coughing during swallowing or chest infection due to saliva soiling in the lungs.

4. Pain: it maybe felt in the larynx or referred to the ear (otalgia) through IX & X CN.

Signs of laryngeal disease1) Voice abnormality (dysphonia): abnormal

voice ranging from aphonia to hoarseness of voice.

2) Stridor.3) Mobility: laryngeal mobility due to swallowing

and phonation (which is normally palpable) may be impalpable in laryngeal disease.

4) Neck lump: this is maybe due to lartngeal disease itself or metastasis to the neck lymphnodes.