Download eustachian tube

ANATOMY OF MIDDLE EAR
MIDDLE EAR CLEFT

EUSTACHIAN TUBE,MIDDLE EAR
CAVITY, ADITUS, ANTRUM, MASTOID
AIR CELLS.
EUSTACHIAN TUBE
AUDITORY OR PHARYNGO TYMPANIC
TUBE CONNECTS NASOPHARYNX WITH
TYMPANIC CAVITY
 ADULT- 36mm LONG AND RUNS
DOWNWARDS, FORWARDS AND
MEDIALLY FROM ITS TYMPANIC END,
FORMING AN ANGLE OF 45* WITH THE
HORIZONTAL

2 PARTS- BONY AND
FIBROCARTILAGINOUS
 BONY PART- POSTERO LATERAL,
1/3RD
 FIBROCARTILAGINOUS PARTANTERO MEDIAL 2/3RD
 2 PARTS MEET AT ISTHMUSNARROWEST PART OF THE TUBE

TYMPANIC END- 5X2cm; situated in anterior
wall of middle ear, a little above the level of
floor.
 PHARYNGEAL END- slit like, vertically.
 Cartilage at this end raises an elevation
called torus tubarius situated in lateral wall of
of nasopharynx, 1-1.25cm behind posterior
end of inferior turbinate.

MUSCLES RELATED TO EUSTACHIAN
TUBE
TENSOR VELI PALATINI- DILATOR
TUBAE
 LEVATOR VELI PALATINI
 SALPINGO PHARYNGEUS

ELASTIN HINGE
 OSTMANN’S PAD OF FAT

LINING OF THE EUSTACHIAN
TUBE
PSEUDO STRATIFIED CILIATED
COLUMNAR EPITHELIUM
INTERSPERSED WITH MUCOUS
SECRETING GOBLET CELLS.
 SUBMUCOSA- RICH IN
SEROMUCINOUS GLANDS
 CILA BEAT IN DIRECTION OF
NASOPHARYNX

DIFFERENCES BETWEEN INFANT
AND ADULT EUSTACHIAN TUBE
LENGTH
 DIRECTION
 ANGULATION AT ISTHMUS
 BONY VERSUS CARTILAGINOUS
PART
 TUBAL CARTILAGE
 DENSITY OF ELASTIN AT THE HINGE
 OSTMANN’S PAD OF FAT

BLOOD SUPPLY
RAMUS MENINGEUS ACCESSORIUS
 ARTERY OF PTERYGOID CANAL
 ASCENDING PHARYNGEAL ARTERY


VENOUS DRAINAGE- PTERYGOID
PLEXUS

NERVE SUPPLY- TYMPANIC PLEXUS
AND SPHENOPALTINE GANGLION
FUNCTIONS
VENTILATION AND REGULATION OF
MIDDLE EAR PRESSURE
 PREVENTS REFLUX OF
NASOPHARYNGEAL SECRETIONS
 CLEARANCE OF MIDDLE EAR
SECRETIONS

TYMPANIC CAVITY
BICONCAVE DISC
 VERTICAL -15mm
 ANTERO-POSTERIOR -13mm
 TRANSVERSE – 6mm at upper
part,2mm at the centre, 4mm at the
lower part

Epitympanu
m (attic)
Mesotympanu
m
Hypotympanu
m
TYMPANIC CAVITY
ROOF- TEGMEN TYMPANI
 FLOOR ANTERIOR WALL
CANAL OF HUGUIER
(CHORDA TYMPANI)
CANAL FOR TENSOR TYMPANI
TYMPANIC ORIFICE FOR ET
THE GLASERIAN FISSURE
(TYMPANIC ARTERY AND ANTERIOR
LIGAMENT OF MALLEUS)

POSTERIOR WALL –
 PYRAMID- TENDON OF STAPEDIUS
 ADITUS FACIAL RECESS/ POSTERIOR SINUSMEDIALLY VIIth NERVE, LATERALLY
CHORDA TYMPANI NERVE, ABOVE
FOSSA INCUDIS
 SINUS TYMPANI- SUBICULUM
BELOW AND PONTICULUS ABOVE

MEDIAL WALL PROMONTARY- BASAL COIL OF
COCHLEA
 OVAL WINDOW
 ROUND WINDOW
 CANAL FOR FACIAL NERVE
 PROMINENCE OF LATERAL
SEMICIRCULAR CANAL
 PROCESSUS COCHLEARIFORMISLEVEL OF GENU OF FACIALNERVE

LATERAL WALL
 TYMPANIC MEMBRANE AND BONY
OUTER ATTIC WAL CALLED SCUTUM

CONTENTS OF MIDDLE EAR
CAVITY
OSSICLES
 MALLEUSHEAD,NECK,HANDLE,LATERAL AND
ANTERIOR PROCESS
 INCUS- BODY, SHORT PROCESS, LONG
PROCESS
 STAPES- HEAD,NECK,ANTERIOR AND
POSTERIOR CRURA AND FOOT PLATE

Malleus
Incus
Stapes
INTRA TYMPANIC MUSCLES
 TENSOR TYMPANI-ATTACHES TO
NECK OF MALLEUS AND TENSES TM


STAPEDIUS- ATTACHES TO NECK OF
STAPES AND HELPS TO DAMPEN
VERY LOUD SOUNDS
TYMPANIC PLEXUS
LIES ON PROMONTARY
 TYMPANIC BRANCH OF
GLOSSOPHARYNGEAL NERVE AND
SYMPATHETIC FIBRES FROM PLEXUS
AROUND INTERNAL CAROTID ARTERY


CHORDA TYMPANI NERVE
MUCOUS MEMBRANE

CILIATED COLUMNAR IN ANTERIOR AND
INFERIOR PART, CUBOIDAL IN
POSTERIOR PART. EPITYMPANUM AND
MASTOID AIR CELLS LINED BY FLAT
NONCILIATED EPITHELIUM
BLOOD SUPPLY
SUPERIOR- SUPERFICIAL PETROSAL,
SUPERIOR TYMPANIC,RAMUS NUTRICIA
INCUDOMALLEI
 INFERIOR- INFERIOR TYMPANIC BRANCH
OF ASCENDING PHARYNGEAL ARTERY
 ANTERIOR- ANTERIOR TYMPANIC
BRANCH OF INTERNAL MAXILLARY
ARTERY;RAMUS TYMPANICI BRANCH OF
INTRNAL CAROTID ARTERY
 POSTERIOR-POSTERIOR TYMPANIC
BRANCH OF STYLOMASTOID ARTERY


VEINS DRAIN INTO ;PTERYGOID
VENOUS PLEXUS

LYMPHATICS DRAIN INTO
RETROPHARYNGEAL AND PAROTID
NODES

NERVE SUPPLY- TYMPANIC BRANCH
OF IXTH CRANIAL
NERVE(JACOBSON’S NERVE)
MASTOID

ADITUS AD ANTRUM- BONY
PROMINENCE OF HORIZONTAL
CANAL LIES ON ITS MEDIAL SIDE
WHILE FOSSA INCUDIS LIES
LATERALLY. FACIAL NERVE
COURSES JUST BELOW THE ADITUS
MASTOD ANTRUM





AIR CHAMBER IN TEMPORAL BONE, LINED
BY FLATTENED SQUAMOUS CELLS
ROOF- TEGMEN ANTRI
ANTERIOR- OPENING OF ADITUS AD
ANTRUM
MEDIAL- POSTERIOR AND HORIZONTAL
SEMICIRCULAR CANALS
LATERAL- SUPRA MEATAL(MACEWEN’S)
TRIANGLE [1.5cm DEEP]
MAST0ID PROCESS
LIES BEHIND TYMPANIC PORTION OF
TEMPORAL BONE
 BONE CORTEX WITH HONEYCOMB OF
AIRCELLS UNDERNEATH
 1. WELL PNEUMATISED OR CELLULAR
 2. DIPLOETIC
 3. SCLEROTC OR ACELLULAR


ARTERIAL SUPPLY- POSTERIOR
TYMPANIC ARTERY FROM
STYLOMASTOID BRANCH OF
POSTERIOR AURICULAR ARTERY

VEINS-MASTOID EMISSARY VEIN,
POSTERIOR AURICULAR VEIN AND
SIGMOID SINUS
THANK YOU