3. Eustachian tube

Eustachian tube

1. Anatomy and Physiology
of the Eustachian Tube
Dr. Krishna Koirala

2. •Linksthepharynxtothemiddleear
•Eustachius(1562) :Pharyngotympanictube
•AntonioValsalva :Eustachiantube
•Developsfromtubotympanicrecesswhichisderivedfrom
endodermof1
st
pharyngealpouch
•36mmlonginadults
•Directedanteriorly,inferiorlyandmediallyfromanteriorwallof
middleearformingangleof45
0
withhorizontalandsagittal
planes
•Entersthenasopharynx1.25cmbehindposteriorendof
inferiorturbinate

4. Parts
•Lateral 1/3-bony
•Medial 2/3-fibro-
cartilaginous
•Junction between 2
parts --isthmus,
narrowest part of
Eustachian tube

6. Anatomy of medial 2/3rd
•Cartilageplate
–Liespostero-medially
–Consistsofmedialand
laterallaminaeseparated
byelastinhinge
•Fibrous tissue and
Ostmann’s fat pad lie infero-
laterally

7. Muscles
1. Tensor veli palatini or dilator tubae
2. Levator veli palatini
3. Salpingopharyngeus
4. Tensor tympani
Nerve supply
1. Sphenopalatine ganglion
2. Mandibular nerve
3. Tympanic plexus

9. •Lining epithelium
−Respiratory epithelium
•Arterial supply
–Ascending pharyngeal & middle meningeal
arteries
•Venous drainage
−Pharyngeal & pterygoid venous plexus
•Lymphatic drainage
−Retropharyngeal node

10. Endoscopic Anatomy
•Medial end forms tubal
elevation / torus tubaris
•Lymphoid collection over
torus is called Gerlach’s tubal
tonsil
•Postero-superior to torus is
fossa of Rosenmüller

11. Adult vs. Child (< 7 yr)

12. Adult vs. Children (< 7 yrs)
ADULT INFANT
Length 36 mm 18 mm
Angle with horizontal 45
0
10
0
Lumen Narrower Wider
Angulation at isthmusPresent Absent
Cartilage Rigid Flaccid
Elastic recoil EffectiveIneffective
Ostmann’s fat More Less

13. Physiology
•Bonypartisalwaysopen
•Fibro-cartilaginouspartclosedatrestandopenson
swallowing,yawning,sneezing
•Activeopeningbycontractionoftensorvelipalatini
•Passiveopeningbycontractionoflevatorveli
palatini(?releasesthetensionontubalcartilage)
•Closure:Elasticrecoilofelastinhingeanddeforming
forceofOstmann’sfatpad

14. E.T. opening

15. Functions
1.Ventilation&maintenanceofatmospheric pressurein
middleearfornormalhearing
2.Drainageofmiddleearsecretionsintonasopharynxby
mucociliaryclearance,pumpingaction&presenceofintra-
luminalsurfacetension
3.Protectionofmiddleearfrom
•Ascendingnasopharyngealsecretions(duetonarrow
isthmus&angulationbetween2partsofE.T.atisthmus)
•Pressurefluctuations
•Loudsoundcomingthroughpharynx

16. Functions

17. Conditions of Dysfunction

18. Bluestone’s Flask
Model

19. Adult vs. Pediatric

20. TM perforation and nose blowing

21. O.M.E. & Barotrauma

22. Grommet insertion in O.M.E.

23. Tests for E.T. function

24. 1. Valsalva Maneuver
•Forcedexpirationwith
mouth&noseclosed
•Otoscopyshowslateral
bulgingofTympanic
membrane

26. 2. Frenzel Maneuver
•Hands free Valsalva
•Compression of nasopharyngeal
air by muscles of tongue
•Otoscopyshowslateralbulging
oftympanicmembrane

27. 3. Toynbee Maneuver
•Morephysiological
•Swallowingwithmouth&
noseclosed
•Otoscopyshowsretraction
oftympanicmembrane

28. •Airpressureisalternatelyincreased&decreased
withinexternalauditorycanal
•Mobilityoftympanicmembraneisobserved
•Normalmobilityindicatesgoodpatencyof
Eustachiantube
4. Pneumatic otoscopy & Siegelization

29. Siegelization

30. Pneumatic Otoscope

31. Normal Tympanic Membrane

32. Eustachian Tube dysfunction

33. Early otitis media with effusion

34. Late otitis media with effusion

35. Acute suppurative otitis media

36. Ear drum perforation

37. 5. Politzerization
•Rubber tube attached to a Politzer bag put into one
nostril and both nostrils are pinched
•Patient asked to swallow or repeat “k”
•Politzer bag is squeezed simultaneously
•Otoscopy shows lateral bulging of ear drum in patent
Eustachian tube

40. 6. E.T. catheterization
•E.T. catheter passed along nasal floor till it touches
posterior wall of nasopharynx
•Catheter rotated 90°medially & pulled forward till it
impinges on posterior nasal septum
•Catheter rotated 180°laterally, & its tip inserted into
opening of E.T.
•Politzer bag attached to outer end of catheter

41. •Air pushed into E.T. catheter by squeezing Politzer
bag
•Examiner hears by Toynbee auscultation tube put in
pt's ear
•Blowing sound normal E.T. patency
•Bubbling soundmiddle ear fluid
•Whistlingsoundpartial E.T. obstruction
•No sound complete obstruction of E.T.

42. Eustachian tube catheter

44. 7. Tymapanometry
•Type C= E.T. dysfunction
•Type B= fluid in middle ear

45. •200 mm H
2
O pressure is created in patient’s external
auditory canal
•Patient asked to swallow 10 times
•Residual pressure in patient’s external auditory canal
after 10th swallow is noted
•Test repeated with -ve 200 mm H
2
O pressure created
in patient’s external auditory canal
8. William’s pressure equalization test

46. William’s Test
Residual Pressure Result
Up to +50 mm H
2
O normal E.T. function
+51 to +100 mm H
2
O mild dysfunction
+101 to +199 mm H
2
O moderate dysfunction
+200 mm H
2
O severe dysfunction

47. 9. Sono-tubometry
•Sound made in pt’s nasal cavity & detected with
stethoscope in patient’s external auditory canal
•Loud sound = patent Eustachian tube
10. Eustachian tube Salpingogram
•Dye instilled through E.T. catheter & X-ray taken
11. C.T. scan & M.R.I. of skull

48. 12. Trans-nasal E.T. video-endoscopy
13. Test for E.T. patency in T.M. perforation
•Saccharinecrystal/antibioticeardrop/
methyleneblueplacedinmiddleearviaeardrum
perforation
•Sweettaste/bittertaste/bluestainingof
secretionsindicatespatentEustachiantube

49. Patulous Eustachian Tube
•Auralfullness,hummingtinnitus,autophony,hearingown
breathsounds(tympanophonia)
•Symptomsresolveinsupineposition,inforwardbendingwith
headbetweenknees,inU.R.T.I.andaggravatedby
mastication
•Otoscopy:T.M.movesduringbreathing
•Associatedconditions:radiationtherapy,hormonaltherapy,
nasaldecongestants,3
rd
trimesterpregnancy,stress,sudden
weightloss,multiplesclerosis
•Treatment:Reassurance,weightgain,oralpotassiumiodide

50. Patulous Eustachian Tube Contd…
•Surgicalinterventions
–Electro-cauterizationofE.T.orifice
–Peri-tubalinjectionwithTeflonpaste
–Transpositionoftensorvelipalatinimusclemedial
topterygoidhamulus
–PluggingofE.T.orificeinMiddleearand
myringotomy&grommetinsertion