Ear anatomy& Physiology Ear anatomy& Physiology and Embryology of the ear and Embryology of the ear

+congenital anomalies +congenital anomalies

Dr. Manal BukhariDr. Manal Bukhari

King Saud University King Saud University OtolaryngologyOtolaryngology

Assistant professorAssistant professor consultant Phonosurgeon consultant Phonosurgeon King Abdulaziz University King Abdulaziz University

Embryology Embryology

Six visceral arches Six visceral arches AuricleAuricle : :first and second first and second

branchial archbranchial arch EACEAC: : first phayrngeal groovefirst phayrngeal groove OssiclesOssicles : :first branchial arch (meckel’s first branchial arch (meckel’s

cartilage)cartilage) malleus head and neck malleus head and neck incus body and short process .incus body and short process .

Second branchial arch(reichert;s Second branchial arch(reichert;s cartilage)cartilage) manubrium of manubrium of malleus ,long and lenticular malleus ,long and lenticular process of incus ,stapesprocess of incus ,stapes

Anatomy of the earAnatomy of the ear

External ear:External ear:

1.1. Auricle :Auricle : Arise from the first and second Arise from the first and second

branchial cleft.branchial cleft. Cartilage +perichondrium +skin Cartilage +perichondrium +skin

(close adherent together) except (close adherent together) except the lobule. the lobule.

2-External auditory canal:2-External auditory canal:First pharyngeal cleft First pharyngeal cleft Length:2.5 cmLength:2.5 cm

Cartilaginous EAC:Cartilaginous EAC:lateral 1/3 fibrocartilage contains lateral 1/3 fibrocartilage contains

apopilosebaceous unitsapopilosebaceous unitsOsseous EAC:Osseous EAC:

• medial 2/3periosteummedial 2/3periosteum• Post sup squamaPost sup squama• The remainder tympanic The remainder tympanic

plateplate• Squmotympanic Squmotympanic

&tympanomastoid sutures&tympanomastoid sutures

• Two constrictionTwo constriction : :• At the medial end of the At the medial end of the

cartilaginous portion and 5 cartilaginous portion and 5 mm from the TMmm from the TM

Relations of external auditory meatusRelations of external auditory meatus

FrontFront: TMJ : TMJ BehindBehind :Mastoid air cell :Mastoid air cell AboveAbove :middle cranial fossa :middle cranial fossa Front and belowFront and below parotid gland parotid gland

Sensory nerve supply:Sensory nerve supply: Greater auricular -(C2,C3)Greater auricular -(C2,C3) Auricular –vagus XAuricular –vagus X Auriculotemporal -Vc mandibularAuriculotemporal -Vc mandibular

Vascular supply:Vascular supply: Auriculotemporal branch of superficial temporal artery ,anteriorlyAuriculotemporal branch of superficial temporal artery ,anteriorly Branches of postauricular division of external carotid artery postriorly.Branches of postauricular division of external carotid artery postriorly.

Lymphatic drainage:Lymphatic drainage: PreauricularPreauricular PostauricularPostauricular Ext jugular lymph nodeExt jugular lymph node

Middle ear cleftMiddle ear cleft

Tympanic membrane:Tympanic membrane:

Outer epithelial layer Outer epithelial layer Middle fibrous layer Middle fibrous layer Inner mucosal layerInner mucosal layer

Parsa Flaccida Parsa Flaccida Parsa Tensa Parsa Tensa Annulus Fibrosus Annulus Fibrosus Notch of RivinusNotch of Rivinus

Tympanic cavity:Tympanic cavity: Bioconcave disc shaped cavity 13mm Bioconcave disc shaped cavity 13mm

ant post ,15 mm in height .ant post ,15 mm in height .

Eustachain tube:Eustachain tube: Post 1/3 osseous portion open in the Post 1/3 osseous portion open in the

ant wall of the tympanic cavity ant wall of the tympanic cavity

Ant membranous cartilaginous portion Ant membranous cartilaginous portion 2/3 end in the nasopharynx 2/3 end in the nasopharynx

LengthLength :3.7 cm ------45 degree from :3.7 cm ------45 degree from horizontalhorizontal

Closed at rest but opened on yawing Closed at rest but opened on yawing and swallowing (and swallowing (tensor paltai muscletensor paltai muscle))

Ossicles:Ossicles: Transmit sound energy Transmit sound energy

from the TM to the oval from the TM to the oval

windowwindow MalleusMalleus ::

head,neck ant and lat processes head,neck ant and lat processes and the handle and the handle ((tensor tympani tensor tympani muscles).muscles).

IncusIncus : :

body ,short processes ,long body ,short processes ,long processprocess

StapesStapes ::

head ,neck ,ant and post crura head ,neck ,ant and post crura and foot plate (and foot plate (stapediusstapedius))

Medial wall:Medial wall:

The promontoryThe promontory : : bony projection covering the bony projection covering the

basal turn of the cochlea.basal turn of the cochlea. Oval windowOval window : :

occupied by the footplate of occupied by the footplate of the stapes ,closes the middle the stapes ,closes the middle ear from the scala vestibuliear from the scala vestibuli

Round windowRound window : : separates the middle ear from separates the middle ear from

scala tympaniscala tympani Facial nerveFacial nerve : :

the horizontal portion lies the horizontal portion lies above the oval windowabove the oval window . .

The horizontal The horizontal semicircular canalsemicircular canal : :

above the second genu of the above the second genu of the facial nerve.facial nerve.

Roof (tegmen tympani)Roof (tegmen tympani)Separate the cavity from middle Separate the cavity from middle

cranial fossacranial fossa

Anterior wall:Anterior wall:

Canal Huguier ,chorda tympani Canal Huguier ,chorda tympani Canal of tensor tympani msCanal of tensor tympani ms Tympanic orifice of ETTympanic orifice of ET Canal of carotid artery Canal of carotid artery

Posterior wallPosterior wall

AditusAditus :which lead backwards :which lead backwards from the epitympanum into from the epitympanum into mastoid antrum mastoid antrum

PyramidPyramid (stapedius tendon) (stapedius tendon)

vertical portion of vertical portion of facial nerve facial nerve

FloorFloor

jugular bulb jugular bulb

Mastoid antrumMastoid antrum::

Situated in the post portion of Situated in the post portion of petrous temporal bone petrous temporal bone

AntAnt :opening of the aditus :opening of the aditus Medial Medial :post and horizontal :post and horizontal

semicircular mcanalssemicircular mcanals RoofRoof (tegmen antri) (tegmen antri) LatLat :squama and macewen’s :squama and macewen’s

triangletriangle

Nerve supply of middle ear :Nerve supply of middle ear : SensorySensory : :

• IX (tympanic plexus) +VIIIX (tympanic plexus) +VII MotorMotor : :

• V3 to tensor tympani msV3 to tensor tympani ms

• VII to stapedial ms VII to stapedial ms

Vascular supply :Vascular supply : Branches of both internal and Branches of both internal and

external carotid arteryexternal carotid artery

Inner earInner ear

Inner ear (labyrinth)Inner ear (labyrinth)

Osseous labyrinthOsseous labyrinth

vestibulevestibule::• lie between the medial wall of lie between the medial wall of

the middle ear and lateral end the middle ear and lateral end of internal auditory canal .of internal auditory canal .

• Oval window in the lateral Oval window in the lateral wallwall

Bony semicircular canalBony semicircular canal• Sup ,post, horizontalSup ,post, horizontal

Bony cochlea;Bony cochlea; • in front the vestibule ,snail in front the vestibule ,snail

shell in shape ,2 1/2 turns, shell in shape ,2 1/2 turns, central axis (central axis (mediolusmediolus )inner )inner wall of the canalwall of the canal

Contain perilymph Contain perilymph =extracellular fluids =extracellular fluids

Membranous labyrinthMembranous labyrinth communicating sacs and communicating sacs and

ducts within the bony cavities ducts within the bony cavities

Saccule &utricleSaccule &utricle (vestibule) (vestibule)

Membranous semicircular Membranous semicircular ductsducts

Cochlear ductCochlear duct (scala media) (scala media)

Membranous labyrinth contain Membranous labyrinth contain endolymph =intracelluar fluids endolymph =intracelluar fluids ↑K,↓Na↑K,↓Na

Organ of corti;Organ of corti;

Scala vestibuliScala vestibuli --oval window --oval window Scala tympaniScala tympani -–round window -–round window

Both contain perilymph Both contain perilymph Scala mediaScala media --endolymph --endolymph

Physiology of hearing Physiology of hearing

Sound energy →air → Sound energy →air → external canal → TM → external canal → TM → Ossicles → cochlear fluid Ossicles → cochlear fluid wave → stimulation of wave → stimulation of basal membrane → basal membrane → shearing of hair cell with shearing of hair cell with tectorial membrane → tectorial membrane → rapid depolarization → rapid depolarization → impulse carried along the impulse carried along the auditory nerve .auditory nerve .

Area advantage :TM 55 Area advantage :TM 55 mm the stapes 3.2mm mm the stapes 3.2mm =17:1=17:1

Lever effect : 1.3:1Lever effect : 1.3:1 Transformer ratio 22:1 Transformer ratio 22:1

25-30 dB gain25-30 dB gain

Central connection of cochlear Central connection of cochlear nerve nerve

The vestibular labyrinth The vestibular labyrinth

Semicircular canalsSemicircular canals =hair cell ►gelatinous =hair cell ►gelatinous cupula ► sheared (angular movements ) cupula ► sheared (angular movements ) ►vestibular nerve .►vestibular nerve .

Utricle and sacculeUtricle and saccule= hair cell ► otoconial = hair cell ► otoconial membrane ► (linear acceleration&pull of the membrane ► (linear acceleration&pull of the gravity) ► vestibular nerve gravity) ► vestibular nerve

The major connection of the vestibular system The major connection of the vestibular system are:are: spinal cord ,cerebellum, external ocular muscle spinal cord ,cerebellum, external ocular muscle

Disease of external ear and Disease of external ear and acute otitis media acute otitis media

Congenital anomalies of external Congenital anomalies of external ear ear

Protruding ear (bat Protruding ear (bat ear): ear): otoplasty otoplasty

PreauricularPreauricular sinussinus: : surgical excision surgical excision

Microtia :Microtia : Atrasia Atrasia Accessory auriclesAccessory auricles RX: RX:

plastic reconstruction plastic reconstruction Bone anchored Bone anchored

hearing aidhearing aid

Perichondritis of pinna:Perichondritis of pinna:

infection of the auricular infection of the auricular cartilage-----necrosis ----cartilage-----necrosis ----deformity.deformity.

it may follow:it may follow: HaematomaHaematoma Surgery Surgery

RX:RX: ABXABX Incision & drainage Incision & drainage Removal of necrotic tissue Removal of necrotic tissue

Otitis externaOtitis externa Acute otitis externa:Acute otitis externa:

Bacterial infection involving the skin of the external Bacterial infection involving the skin of the external canalcanal

Pathophysiology:Pathophysiology: aggressive washing the wax or retention water aggressive washing the wax or retention water Microtruma (cotton swabs,fingernails )Microtruma (cotton swabs,fingernails )

PathogensPathogens; ; pseudomonas aeruginosa, staphlococcus (furuncle)pseudomonas aeruginosa, staphlococcus (furuncle)

SSxSSx: : pain ,tragal tendreness otalgia ,pruritus, edematous pain ,tragal tendreness otalgia ,pruritus, edematous

erythematous EAC, conductive hearing loss.erythematous EAC, conductive hearing loss. RX:RX:

suction cleaning suction cleaning Ear drop Ear drop Analgesia Analgesia Antibiotic Antibiotic

Eczematous otitis externa:Eczematous otitis externa:

Allergic dermatitis Allergic dermatitis

SSx;SSx; pruritis ,redness oedema , pruritis ,redness oedema ,

mild pain,dry scaly skinmild pain,dry scaly skin

RX:RX: recognize the allergenrecognize the allergen Hydrocortisone cream Hydrocortisone cream Antihistamin Antihistamin Coal tar ointment ,silver nitrate Coal tar ointment ,silver nitrate

,canalplasty ( ,canalplasty (chronic stagechronic stage))

Seborrhoeic otitis Seborrhoeic otitis externa :externa :

Greasy, scaling and Greasy, scaling and crusting condition crusting condition

Cause:Cause: abn sebum and waxabn sebum and wax

SSx:SSx: Greasy yellow scales Greasy yellow scales itching itching

RX:RX: Shampoo selenium Shampoo selenium

sulphide and ketoconazole sulphide and ketoconazole Ointment; salicylic acid and Ointment; salicylic acid and

sulpher 2%sulpher 2%

Herpetic lesionsHerpetic lesions:: Herpes simplex (acyclovir in severe Herpes simplex (acyclovir in severe

casescases ) ) herpes zoster oticus herpes zoster oticus

• Sever pain Sever pain • Vesication Vesication • Cranial nerve lesion deafness SNHLCranial nerve lesion deafness SNHL• VertigoVertigo• Facial nerve palsies Facial nerve palsies

Ramsay hunt syndrom Ramsay hunt syndrom RX:RX:

• oral and topical acyclovir earlyoral and topical acyclovir early

Otomycosis :Otomycosis : Aspergillus ,candidaAspergillus ,candida

SSX:SSX: moist tissue –paper dotted moist tissue –paper dotted

gray membran, prurtic gray membran, prurtic RXRX

: suction cleaning: suction cleaning Fungicides :Fungicides :

• nystatin ,econazolnystatin ,econazol

Otitis externa malignans (osteomyelitis Otitis externa malignans (osteomyelitis of skull base):of skull base):

Pseudomonas infection occurring in elderly Pseudomonas infection occurring in elderly diabetic patients .diabetic patients .

SSX:SSX: Granulation tissue in EAC at the bony Granulation tissue in EAC at the bony

cartilagenous junction cartilagenous junction Persist otalgia, otorrhea Persist otalgia, otorrhea Crainal nerve involvement Crainal nerve involvement VII, IX ,X XI ,XII,V,VIVII, IX ,X XI ,XII,V,VI

DX ;DX ; CT scan, bone scan ,culture CT scan, bone scan ,culture

RXRX: : diabetic controldiabetic control Prolonged parentral anti- pseudomonus abxProlonged parentral anti- pseudomonus abx Ear drop Ear drop Debridement Debridement Hyperbaric oxygen Hyperbaric oxygen

Acute otitis mediaAcute otitis media Inflammation of the middle ear cavity (<3 Inflammation of the middle ear cavity (<3

weeks)weeks)

Pathophysiology :Pathophysiology : ET dysfunction ,spread of the infection via ET dysfunction ,spread of the infection via

submucosal lymphatic or direct spreadsubmucosal lymphatic or direct spread Pathogens;Pathogens;

S,pneumonia, H, influnza.Moraxella S,pneumonia, H, influnza.Moraxella Risks:Risks:

Craniofacial abnCraniofacial abn Rec URTIRec URTI Day care Day care Bottle feeding Bottle feeding smoking smoking immunological disorders IgA ,IgG deficienciesimmunological disorders IgA ,IgG deficiencies Ciliary dysfunction Ciliary dysfunction Adenoid hypertrophy Adenoid hypertrophy GERDGERD NGT NGT

SSX:SSX: Otalgia,aural fullness, hearing loss, Otalgia,aural fullness, hearing loss,

tinnitus ,fevertinnitus ,fever Hyperemic TM ,non mobile bulgingTM ,air Hyperemic TM ,non mobile bulgingTM ,air

fluid level fluid level RXRX;;

oral ABX for 10 days oral ABX for 10 days Antipyretics , analgsia oral and nasal Antipyretics , analgsia oral and nasal

decongestantsdecongestants Myringotomy ►sever otalgia Myringotomy ►sever otalgia

Acute mastoditis Acute mastoditis

Management of recurrent Management of recurrent acute otitis media :acute otitis media :

Myringotomy with pressure Myringotomy with pressure equalization tube;equalization tube;

Secretory otitis media (otitis media Secretory otitis media (otitis media with effusion)with effusion)

Persistence of fluid in the middle ear Persistence of fluid in the middle ear space without evidence of infection.space without evidence of infection.

SSX:SSX: nonmobile TM, airfluid levels, aural nonmobile TM, airfluid levels, aural

fullness, hearing loss,fullness, hearing loss, DX:DX:

tympanometrytympanometry RX:RX:

ABx,ABx, Myringotomy with pressure Myringotomy with pressure

equalization tube.equalization tube.