Anatomy, Physiology of ENT for Paramedics - Dr. Fuad Ridha

8/6/2019 Anatomy, Physiology of ENT for Paramedics - Dr. Fuad Ridha

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Fuad Ridha Mahabot

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Anatomy of the EarEar - organ of

hearing andmaintainingequilibrium

3 parts:

external earmiddle ear

inner ear

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external ear pinna/auricle

external auditory canal tympanic membrane

middle ear Eustachian tube

tympanic cavity

mastoid air cells

inner ear

cochlea vestibular apparatus

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External Ear

Pinnaframework of a single

piece of cartilage

covered with skin(except for the lobule)

has lateral and medialsurfaces

also has ridges anddepressions

perichondritis infectionof the perichondrium ofpinna extremely painful

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External AuditoryCanalextends from the

concha to the tympanic

membrane24mm long

not a straight tube

2 partsouter 1/3 cartilaginous

(8mm)

inner 2/3 bony (16mm)

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cartilaginous partcontinuation of cartilage

from the pinna

skin coverings - thick,contain ceruminous and

pilosebaceous glands wax

bony part

no hair/glandprox aspect - isthmus -

narrowing part

FB/wax may getimpacted in the isthmus

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Tympanic membrane(drumhead)

forms partitionbetween EAC and

middle earoblique in shape

divided into pars tensa - forms most

of the tympanicmembrane

pars flaccida - situatedabove the lateralprocess of malleus

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Middle Ear

also called as tympanic cavity

between external and middle ear

functions

transmits sound wave from external ear to the innerear through the chain of ear ossicles

transforms air borne vibration liquid bornevibration

increases intensity of sound by 10x withoutchanging the frequency

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contents of middle ear

three ossicles (malleus,incus, stapes)

ligaments of ear ossicles

two muscles (tensortympani and stapedius)

vessels

nerve - chorda tympani andtympanic plexus

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Eustachian Tubeconnects nasopharynx to

the tympanic cavity

adult - runs in a oblique line

child - straight line

closed at rest

2 parts

posterolateral 1/3 - bony

anteromedial 2/3 -

fibrocartilaginous

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functionsregulation of middle ear

pressure

protection against refluxof nasopharyngeal

secretionsmiddle ear clearence of

secretions

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Inner Ear

(Labyrinth)

important organ ofhearing andbalance

consists ofbony labyrinth

membranouslabyrinth

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Bony Labyrinth

complex spaces insidethe petrous part of thetemporal bone filledwith perilymph

consists of

vestibule

semicircular canal

cochlea

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Membranous labyrinth

delicate complexstructures seen insidethe bony labyrinth

contains endolymph

consists of

cochlear duct

utricle/saccule

semicircular ductendolymphatic duct

and sac

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Physiology of Hearing and

EquilibriumDivided into

mechanicalconduction of sound

(conductiveapparatus)

transduction ofmechanical energy to

electrical impulsesconduction of

electrical impulses tothe brain

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sound signal collected by pinna passes throughEAC strikes the tympanic membrane

vibration of tympanic membrane transmitted tostapes footplate through the chain of ossicles

movement of stapes footplate causes pressurechanges in labyrinthine fluid which moves basilarmembrane

thus it stimulates hair cells of organ of Corti acts

as transducer

conduct mechanical energy intoelectrical impulses travel along auditory nerve tothe brain

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Physiology of Equilibrium

Balance of the various parts of the body duringstatic or dynamic positions are maintained by 4organs

Vestibular apparatus (inner ear)Eye

Posterior column of the spinal cord

Cerebellum

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Vestibular Apparatus

Vestibular apparatus of the 2sides act as one unit

Vestibular fluids move withhead movements

Detects head position andmovements needed forpostural adjustments

Head movements can be

Angular acceleration Semicircular canals: Cristae

Linear acceleration

Utricle and saccule: Maculae

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Anatomy of the NoseNoserespiratory passage

organ of smell

External nosepyramidal in shape

osteocartilagenous

framework covered bymuscles and skin

upper 1/3 - bony (nasalbone)

lower 2/3 - cartilaginous

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Nasal Septum

3 parts:Membranous: Medial

crura of alar cartilage

Cartilagenous:

Quadrilateral cartilageBony: Perpendicular plate of

ethmoid

Perpendicular plate of thevomer

Nasal crest of maxilla

Nasal crest of palatine

Rostrum of sphenoid

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Littles area Caudal part of the nasal

septum which has a richsubmucosal arterialnetwork - septal

branches of Anterior ethmoidal

Sphenopalatine Greater palatine Superior labial

Prone for drying effect ofinspired air and tomicrotrauma due to

picking of the nose Commonest cause and site

of epistaxis in children

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Lateral Wall of Nasal

Cavity

marked by threeprojections calledturbinates or conchae.

types

inferior

middle

superior

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inferior meatus

lowermost turbinatescontains opening of

nasolacrimal duct

middle meatusrounded by bulge called

bullae ethmoidalisbelow the bullae - hiatus

semilunaris leads toethmoidal infundibulum

superior meatuspost 3rd of lateral wallcontains opening

through post ethmoidalsinus

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Anatomy of Paranasal

SinusesAir filled spaces in the

facial bones, lined bymucosa which drains into

the nasal cavity bymuco-ciliary function

Functionair-conditioning

resonance to voice

thermal insulators

lighten skull bone


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Two groups

Anterior group: Drainsinto middle meatusMaxillary, frontal and

anterior ethmoids

Posterior group: Drainsinto superior meatusPosterior ethmoids and

the sphenoid


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Physiology of NoseFunction of noserespiration

air conditioning ofinspired air

protection of lowerairway

vocal resonance

nasal reflex function

olfaction

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respiration

natural pathway of breathing

since newborn

air conditioning of inspired air

acts as an air-conditioner

filters and purifies air

adjusts its temperature andhumidity before it passesonto the lungs

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protection of lower

airwaymuco-ciliary

mechanism secretes mucous

secretion

inspired bacteria,viruses and dustyparticles entrappedinto viscous mucous carried out to thenasopharynxswallowed

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vocal resonance

phonating certain nasalconsonants (M/N/NG)

nasal reflexes

several reflexes whichis initiated in nasalmucosa

smell of food reflexsecretion of saliva and

gastric juiceirritation of nasal

mucosa sneezing

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olfaction (smell)

important forpleasure and forenjoying the tastesof food

when nose blocked,food tastes blandand unpalatable

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Anatomy of Larynxlarynx - organ ofproduction of voice

also an air passage

primary functionProtection of tracheo-

bronchial tree

secondary function

Phonation (generation ofsound)

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Framework of the

larynx

Hyoid bone

Unpaired cartilages

EpiglottisThyroid cartilage

Cricoid cartilage

Paired cartilagearytenoid cartilage

corniculate cartilage

cuneiform cartilage

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thyroid cartilage largest of all

vocal cord attached tomiddle of thyroid cartilage

cricoid cartilage

ring shape below thyroidcartilage

epiglottis located at the anterior wall

of laryngeal inletant surface connected to

the tongueand hyoid bone

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arytenoid cartilage

pyramidal in shapebase articulates with

cricoid cartilage

has vocal process togive attachment to vocal

cordcorniculate cartilagearticulates with apex of

arytenoid cartilage

cuneiform cartilagesituated infront ofcorniculate cartilage

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Vocal cords

two pearly white bands

extending from middle ofthyroid angle to vocalprocess of arytenoid

for phonationabductors - posterior

cricoarytenoid

adductors - lateralcricoarytenoid,interarytenoid,thyroarytenoid

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Laryngeal Joints

cricoarytenoid jointhelps by abducting and

adducting vocal cord

cricothyroid jointbetween inferior cornu

and thyroid cartilageand at side of cricoidcartilage

for rotatory and glindingmovement

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Muscles of the Larynx

Intrinsic

Extrinsic

Intrinsic - acts on vocalcord / laryngeal inlet

acting on vocal cords abductors - posterior

cricoarytenoid

adductors - lateralcricoarytenoid,interarytenoid,thyroarytenoid

Posterior cricoarytenoid

Lateralcricoarytenoid

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acting on laryngeal inlet thyroepiglottic

interarytenoid aryepiglottic

Extrinsic - attach larynx tosurrounding structures

elevators -stylopharyngeus,salphingopharyngeus,palatopharyngeus,thyrohyoid (primary);

mylohyoid, digastric,stylohyoid, geniohyoid(secondary)

depressors -sternohyoid,sternothyroid,

omohyoid47


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Physiology of LarynxFunction of larynxprotection of lower

airways

phonation

respiration

fixation of the chest

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protection of lower airways

when food is swallowed, air entry into airpassage is prevented by closure of laryngealopening

respiratory also ceased when food in contact

with post pharyngeal wallif foreign body came in contact with laryngeal

mucosa cough is commenced toexpel/dislodge foreign particle

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phonation

adduction of vocalcord

increase infraglotticair pressure from

lungsair force of open

vocal cord vibration of vocalcord producessound

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Sound ProductionA) Vocal cords closed immediately prior to phonation (voice production).B) Air Pressure develops below vocal cords due to air from lungs during exhalation.C) Vocal cords separate briefly with the release of air. (1) Arrow points to the upper edge ofthe vocal cord.D) Vocal cords re-approximate. (2) Arrow points to the lower edge of vocal cord.

E) Vocal cords together again.51


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Thank You

Anatomy, Physiology of ENT for Paramedics - Dr. Fuad Ridha

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