Eustachian tube

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

2. • Links the pharynx to the middle ear
• Eustachius (1562) : Pharyngotympanic tube
• Antonio Valsalva : Eustachian tube
• Develops from tubotympanic recess which is derived from
endoderm of 1st pharyngeal pouch
• 36 mm long in adults
• Directed anteriorly, inferiorly and medially from anterior wall of
middle ear forming angle of 450 with horizontal and sagittal
planes
• Enters the nasopharynx 1.25 cm behind posterior end of
inferior turbinate

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
• Cartilage plate
– Lies postero-medially
– Consists of medial and
lateral laminae separated
by elastin hinge
• 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 isthmus Present Absent
Cartilage Rigid Flaccid
Elastic recoil Effective Ineffective
Ostmann’s fat More Less

13. Physiology
• Bony part is always open
• Fibro-cartilaginous part closed at rest and opens on
swallowing , yawning, sneezing
• Active opening by contraction of tensor veli palatini
• Passive opening by contraction of levator veli
palatini ( ? releases the tension on tubal cartilage)
• Closure : Elastic recoil of elastin hinge and deforming
force of Ostmann’s fat pad

14. E.T. opening

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

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
• Forced expiration with
mouth & nose closed
• Otoscopy shows lateral
bulging of Tympanic
membrane

26. 2. Frenzel Maneuver
• Hands free Valsalva
• Compression of nasopharyngeal
air by muscles of tongue
• Otoscopy shows lateral bulging
of tympanic membrane

27. 3. Toynbee Maneuver
• More physiological
• Swallowing with mouth &
nose closed
• Otoscopy shows retraction
of tympanic membrane

28. • Air pressure is alternately increased & decreased
within external auditory canal
• Mobility of tympanic membrane is observed
• Normal mobility indicates good patency of
Eustachian tube
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
• Whistling sound  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 H2
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 H2
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 H2
O normal E.T. function
+ 51 to + 100 mm H2
O mild dysfunction
+ 101 to + 199 mm H2
O moderate dysfunction
+ 200 mm H2
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
• Saccharine crystal / antibiotic ear drop /
methylene blue placed in middle ear via ear drum
perforation
• Sweet taste / bitter taste / blue staining of
secretions indicates patent Eustachian tube

49. Patulous Eustachian Tube
• Aural fullness, humming tinnitus, autophony, hearing own
breath sounds (tympanophonia)
• Symptoms resolve in supine position, in forward bending with
head between knees, in U.R.T.I. and aggravated by
mastication
• Otoscopy: T.M. moves during breathing
• Associated conditions: radiation therapy, hormonal therapy,
nasal decongestants, 3rd trimester pregnancy, stress, sudden
weight loss, multiple sclerosis
• Treatment: Reassurance, weight gain, oral potassium iodide

50. Patulous Eustachian Tube Contd…
• Surgical interventions
– Electro-cauterization of E.T. orifice
– Peri - tubal injection with Teflon paste
– Transposition of tensor veli palatini muscle medial
to pterygoid hamulus
– Plugging of E.T. orifice in Middle ear and
myringotomy & grommet insertion