Typanic membrane and blood supply nerve supplyb

1. TYMPANIC MEMBRANE AND
BLOOD AND NERVE SUPPLY
OF MIDDLE EAR
BY MJ JOHN PAUL

2. TYMPANIC
MEMBRANE

3. TYMPANIC MEMBRANE
• It forms the partition between external acoustic canal and middle ear.
• It is obliquely set and posterosuperior part is more lateral than anteroinferior part
• 9MMTALL ,8-9MMWIDE,0.1MMTHICK
• Divided into
1 pars tensa
2pars flaccida{SHRAPNELLS MEMBRANE}

4. PARSTENSA
Forms most of tympanic membrane
Its periphery is thickened to form fibrocartilaginous ring called annulus tympanicus and it fits
in tympanic sulcus.
Central part of pars tensa is tented inwards at level of tip of malleus and is called umbo.
bright cone of light can be seen radiating from tip of malleus to periphery in anteroinferior
quadrant.

5. PARS FLACCIDA
• SITUATEDABOVE LATERAL PROCESS OF MALLEUS BETWEEN NOTCH OF
RIVINUSANDANTERIORAND POSTERIOR MALLEAL FOLDS.
• IT IS NOT SOTAUT AND MAYAPPEAR SLIGHTLY PINKISH
• VARIOUS LANDMARKSARE SHOWN ON LATERAL SURFACE OFTYMPANIC
MEMBRANE.

6. LAYERS OF TYMPANIC MEMBRANE
• CONSIST OF THREE LAYERS
• 1 OUTER EPITHELIAL LAYERWHICH IS CONTINOUSWITH SKIN LINING MEATUS
• 2 INNER MUCOSAL LAYERWHICH IS CONTINOUSWITH MUCOSA OF MIDDLE
EAR.
• 3 MIDDLE FIBROUS LAYER ENCLOSES HANDLE OF MALLEUSAND HASTHREE
TYPES OF FIBRES RADIAL ,CIRCULARAND PARABOLIC.

8. BLOOD SUPPLY OF MIDDLE EAR
• MIDDLE EAR IS SUPPLIED BY SIXARTERIES OUT OFWHICHTWOARE MAIN.
1. ANTERIORTYMPANIC BRANCH OF MAXILLARY ARTERYWHICH SUPPLIES
TYMPANIC MEMBRANE.
2. STYLOMASTOID BRANCH OF POSTERIORAURICULARARTERYWHICH SUPPLIES
MIDDLE EARAND MASTOID AIR CELLS

9. FOUR MINORVESSELS
1. PETROSAL BRANCH OF MIDDLE MENINGEALARTERY.
2. SUPERIORTYMPANIC BRANCH OF MIDDLE MENINGEALARTERYTRAVERSING
ALONG CANAL FORTENSORTYMPANI MUSCLE.
3. BRANCH OF ARTERY OF PTERYGOID CANAL.
4.TYMPANIC BRANCH OF INTERNAL CAROTID
VEINS DRAIN INTO PTERYGOIDVENOUS PLEXUSAND SUPERIOR PETROSAL SINUS.

10. NERVE SUPPLY OF MIDDLE EAR
TYMPANIC PLEXUS
It is a plexus of nerves on promontory in medial half of middle ear.it is formed by
1. tympanic branch of glossopharyngeal nerve
2. superior and inferior corticotympanic nerve
3. branch from facial ganglion
Tympanic plexus supplies mucous membrane of middle ear, mastoid air cells and bony eustachian
tube.The lesser petrosal nerve derived from it contains secretomotor fibres of glossopharyngeal
nerve to supply parotid gland via otic ganglion.

11. THANKYOU