1. Anatomy , test and disorders
of Eustachian Tube
BY
DR.VIJAYASUNDARAM
ASSOCIATE PROFESSOR1

2. History
• Bartolomeus Eustachius first described it
as pharyngo-tympanic tube in 1562.
• Antonio Valsalva named it Eustachian
tube.
2

3. Embryology
• Develops from tubo-tympanic recess, derived from
endoderm of 1st pharyngeal pouch.
• the distal portion of the pouch expands and forms
middle ear cavity
• Proximal portion forms the Eustachian tube
• cartilage and muscles develop from surrounding
mesoderm
3

4. 4

5. Anatomy
5

6. Anatomy
• 36 mm long in adults.
• Directed anteriorly, inferiorly & medially from anterior wall of
M.E., forming angle of 450 with horizontal
• Enters naso-pharynx 1.25 cm behind posterior end of inferior
turbinate.
• Channel connecting tympanic cavity and nasopharynx
• lumen of the Eustachian tube is roughly triangular, measuring
2-3 mm vertically and 3-4 mm horizontally.
6

7. Angulation
7

8. Pharyngeal opening
8

9. Parts
• Lateral 1/3 is bony
• Medial 2/3 is fibro-
cartilaginous.
• Junction b/w 2 parts is
isthmus, narrowest part
of Eustachian Tube.
9

10. Anatomy of medial 2/3rd
Cartilage plate lies postero-
medially & consists of medial
+ lateral laminae separated
by elastin hinge. Fibrous
tissue + Ostmann’s fat pad lie
antero-laterally.
10

11. • Bony part :
• 12mm long
• widest at tympanic end
• gradually narrows towards isthmus (2mm)
• Thin plate of separating from tensor
tympani superiorly
• Plate of bone separating from internal
carotid medially
11

12. • Cartilaginous part
• 24mm long
• Cartilage forms posteromedial wall and a small
portion anterolaterally
• sits in a groove between petrous temporal bone
and greater wing of sphenoid
• nasopharyngeal opening surrounded by tubal
elevation above and behind
• Fossa of Rosen Muller lying behind this tubal
elevation
12

13. Anatomy
• Lining epithelium: pseudo stratified ciliated columnar
• Arterial supply: ascending pharyngeal &
middle meningeal arteries
• Venous drainage: pharyngeal & pterygoid
venous plexus
• Lymphatic drainage: retropharyngeal node
13

14. Anatomy
Muscle attachments:
Muscles attached to ET
Levaor palati – lower surface of petrous bone and cartilage and
fascia of upper carotid sheath
Tensor palati- bony wall of scaphoid and whole length of short
cartilaginous flange
Salphingo pharyngeus – inferior part of cartilage near its
pharyngeal end
Tensor tympani – cartilage of ET, surrounding bony canal and
greater wing of sphenoid
14

15. Nerve supply
• Tubal mucosa – tympanic branch of cranial
nerve IX
• Tensor veli palatini - Mandibular branch of
trigeminal
15
• Levator veli palatini
Pharyngeal plexus
• Salpingo pharygeus

16. Endoscopic Anatomy
• Medial end forms tubal
elevation / torus tubarius
• Lymphoid collection over
torus is called Gerlach’s tubal
tonsil.
• Postero-superior to torus is
fossa of Rosenmüller.
16

17. Adult vs. Child (< 7 yr)
17

18. Adult vs INFANT
ADULT INFANT
Length 36 mm 18 mm
Angle with horizontal 45 0 10 0
Lumen Narrower Wider
Angulation at isthmus Present Absent
Cartilage Rigid Flaccid
Elastic recoil Effective Ineffective
Ostmann’s fat More Less
18

19. Infant E. tube
• wider shorter and more horizontal
So secretions even milk can regurgitate from
nasopharynx to middle ear if infant not fed in head
up position
19

20. Physiology
• Bony part is always open.
• Fibro-cartilaginous part is closed at rest.
• Opens on:
1. swallowing
2. yawning
3. sneezing
4. forceful inflation
20

21. Physiology
• Opens actively by contraction of tensor veli palatini &
passively by contraction of levator veli palatini (it
releases the tension on tubal cartilage).
• Closes by elastic recoil of elastin hinge + deforming
force of Ostmann’s fat pad.
21

22. E.T. opening
22

23. Functions
1. Ventilation & maintenance of atmospheric
pressure in middle ear for normal hearing
2. Drainage of middle ear secretions into
nasopharynx by muco-ciliary clearance,
pumping action of Eustachian tube &
presence of intra-luminal surface tension
23

24. Functions
3. Protection of middle ear from:
– Ascending nasopharyngeal secretions due to
narrow isthmus & angulation between 2 parts of
E.T. at isthmus
– Pressure fluctuations
– Loud sound coming through pharynx
24

25. Functions
25

26. Conditions of Dysfunction
26

27. EVALUATION OF ET
• History
• Fullness of ears
• Pain and discomfort
• Hearing loss
• Tinnitus
• Dizziness
27

28. EVALUATION OF ET
Physical examination
• Retracted TM
• Middle ear effusion
• Pneumatic otoscopy
• Postnasal examination
• Endoscopic examination
• Valsalva maneuver
• Tonybee test
• Politzer test
• Sonotubometry
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29. Tests for E.T. function
29

30. ET Function Tests
• VALSALVA TEST
– Principle: positive pressure in the nasopharynx causes air
to enter the Eustachian tube
30

31. – Tympanic membrane perforation- a hissing sound
– Discharge in the middle ear- cracking sound
– Only 65% of persons can do this test.
– Contraindications:
• Atrophic scar of tympanic membrane which can rupture
• Infection of nose & nasopharynx
31

32. • Politzer test
– Done in children who are unable to perform valsalva
test.
– Olive shaped tip of the politzer’s bag is introduced
into the patient’s nostril on the side of which the tubal
function is desired to be tested
– Other nostril closed & the bag compressed while at
the same time the patient swallows or says “ik,ik,ik”
32

33. – By means of an auscultation tube a hissing sound
is heard.
– Compressed air can also be used instead of
politzer’s bag
– Test is also therapeutically used to ventilate the
middle ear.
33

34. • Catheterisation
34

35. • Procedure for Catheterisation
35
•Nose is anaesthetised
•E Tube catheter passed along the floor of nose till it
reaches naso pharynx
•Rotated 90deg medially
•Pulled back till posterior border of nasal septum
engaged
•Rotated 180 deg laterally – tip lies against tubular
opening
• Politzer’s bag connected
• Air insufflated
• Entry of air to middle ear verified (lateral bulging of
t.m)

36. 6. E.T. catheterization
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
Whistling sound = partial E.T. obstruction
No sound = complete obstruction of E.T.
36

37. – Complications:
• Injury to Eustachian tube opening
• Bleeding from nose
• Transmission of nasal & nasopharyngeal infection into
middle ear
• Rupture of atrophic area of tympanic membrane
37

38. • Toynbee’s test
– Uses negative pressure
– Ask the patient to swallow while nose is pinched
– Draws air from middle ear to nasopharynx – inward
movement of t.m.
38

39. • Tympanometry (inflation-deflation test)
– +Ve & -ve pressures are created in the external ear
and the patient swallows repeatedly
– in patients with perforated or intact tympanic
membrane
• Radiological Test
• Saccharine/ Methylene blue Test
– Saccharine solution
– Methylene blue dye
– Ear drops into ear with TM perforation
• Sonotubometry
39

40. Disorders of ET
40

41. Tubal Blockage
EROSION OF INCUDOSTAPEDIAL JOINT
RETRACTION POCKET/CHOLESTEATOMA
ATELECTATIC EAR/PERFORATION
OME(THIN WATERY OR MUCOID DISCHARGE)
TRANSUDATE IN ME/HAEMORRHAGE PROLONGED TUBAL BLOCKAGE/DYSFUNCTION
RETRACTION OF TM
-VE PRESSURE IN ME
ABSORPTION OF ME GASES
ACUTE TUBAL BLOCKAGE
41

42. mechanical
• intrinsic
• Extrinsic
functional •Collapse
both
Block
42

43. • Symptoms of tubal occlusion
– Otalgia
– Hearing loss
– Popping sensation
– Tinnitus
– Disturbances of equilibrium
• Signs of tubal occlusion
– Retracted TM
– Congestion along the handle
of malleus and pars tensa
– Transudate behind TM
43

44. • Clinical causes of ET obstruction
– Upper respiratory tract infection
– Allergy
– Sinusitis
– Nasal polypi
– DNS
– Hypertrophic adenoids
– Nasopharyngeal tumour/ mass
– Cleft palate
– Submucous cleft palate
– Down’s syndrome
44

45. Adenoids
• Adenoids cause tubal dysfunction by:
– Mechanical obstruction of the tubal opening
– Acting as reservoir for pathogenic organisms
– Inflammatory mediators in allergy cause tubal
blockage
• Adenoids can cause otitis media with effusion or
recurrent acute otitis media
• Adenoidectomy
45

46. 46

47. large adenoid blocking left et
47

48. Cleft palate
• Tubal dysfunction due to:
– Abnormalities of torus tubaris
– Tensor veli palatini doe not insert into the torus
tubaris
• Otitis media with effusion is common in these
patients
48

49. Down’s syndrome
• Dysfunction due to:
– Poor tone of tensor veli palatini
– Abnormal shape of nasopharynx
49

50. Barotrauma
• Non suppurative condition resulting from failure
of E Tube to maintain M Ear pressure at ambient
atmospheric level
• Cause:
– Rapid descent during air flight
– Under water diving
– Compression in pressure chamber
• When atm pressure > M E pressure by critical
pressure of 90mm Hg E T gets locked – Negative
pressure in ME
• T M retraction - transudation/ h’ge
50

51. Retraction Pockets & ET
51

52. • Any obstruction in the ventilation pathway
retraction pockets or atelectasis of tympanic
membrane
– Obstruction of Eustachian tube  total atelectasis of tm
– Obstruction at additus  cholesterol granuloma &
collection of mucoid discharge in mastoid air cells
52

53. • Other changes
– Thin atrophic TM
– Cholesteatoma
– Ossicular necrosis
– Tympanosclerotic changes
• Management
– Repair of irreversible pathologic processes
– Establishment of ventilation
53

54. Patulous Eustachian Tube
• ET is abnormally patent
• Causes:
– Idiopathic, rapid weight loss, pregnancy (esp 3rd
trim) & multiple sclerosis
• Chief complaints
– Autophony, hearing his own breath sounds
• Pressure changes in the nasopharynx are easily
transmitted to the ME
• Movements of the TM can be seen with
inspiration & expiration
54

55. • Management
– Acute cases Usually self-limiting
– Weight gain & oral administration of KI
– Long standing cases = cauterisation/ insertion of grommet
55

56. EXAMINATION OF EUSTACHIAN TUBE
Pharyngeal end of eustachian tube :posterior
rhinoscopy, rigid nasal endoscope or flexible
nasopharyngoscope
Tympanic end :microscope or endoscope
Simple examination of TM may reveal retraction
pockets or fluid in the me
Movements of TM with respiration point to
patulous eustachian tube 56

57. • Aetiologic causes of eustachian tube
dysfunction assessed through:
– Nasal examination
– Endoscopy
– Tests of allergy
– CT scan of temporal bones
– MRI to exclude multiple sclerosis
57

58. 58