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Anatomy & 
Physiology of 
Eustachian Tube 
Seema S 
1
History 
• Bartolomeus Eustachius first described it 
as pharyngo-tympanic tube in 1562. 
• Antonio Valsalva named it Eust...
Embryology 
3
Embryology 
• Develops from tubo-tympanic recess, derived 
from endoderm of 1st pharyngeal pouch. 
4
5
Anatomy 
6
Anatomy 
• 36 mm long in adults. 
• Directed anteriorly, inferiorly & medially from anterior 
wall of M.E., forming angle ...
Angulation 
8
Pharyngeal opening 
9
Parts 
• Lateral 1/3 is bony 
• Medial 2/3 is fibro-cartilaginous. 
• Junction b/w 2 parts is 
isthmus, narrowest part 
of...
Anatomy of medial 2/3rd 
Cartilage plate lies postero-medially 
& consists of medial 
+ lateral laminae separated 
by elas...
Anatomy 
• Lining epithelium: pseudo stratified ciliated columnar 
• Arterial supply: ascending pharyngeal & 
middle menin...
Anatomy 
Muscle attachments: 
1. tensor veli palatini or dilator tubae 
2. levator veli palatini 
3. salpingopharyngeus 
1...
Nerve supply 
• Tubal mucosa – tympanic branch of cranial 
nerve IX 
• Tensor veli palatini - Mandibular branch of 
trigem...
Endoscopic Anatomy 
• Medial end forms tubal 
elevation / torus tubarius 
• Lymphoid collection over 
torus is called Gerl...
Adult vs. Child (< 7 yr) 
16
Adult vs INFANT 
ADULT INFANT 
Length 36 mm 18 mm 
Angle with horizontal 45 0 10 0 
Lumen Narrower Wider 
Angulation at is...
Infant E. tube 
• wider shorter and more horizontal 
So secretions even milk can regurgitate from 
nasopharynx to middle e...
Physiology 
• Bony part is always open. 
• Fibro-cartilaginous part is closed at rest. 
• Opens on: 
1. swallowing 
2. yaw...
Physiology 
• Opens actively by contraction of tensor veli palatini & 
passively by contraction of levator veli palatini (...
E.T. opening 
21
Functions 
1. Ventilation & maintenance of atmospheric 
pressure in middle ear for normal hearing 
2. Drainage of middle e...
Functions 
3. Protection of middle ear from: 
– Ascending nasopharyngeal secretions due to 
narrow isthmus & angulation be...
Functions 
24
Conditions of Dysfunction 
25
Tests for E.T. function 
26
ET Function Tests 
• VALSALVA TEST 
– Principle: positive pressure in the nasopharynx causes air 
to enter the Eustachian ...
– Tympanic membrane perforation- a hissing sound 
– Discharge in the middle ear- cracking sound 
– Only 65% of persons can...
• Politzer test 
– Done in children who are unable to perform valsalva 
test. 
– Olive shaped tip of the politzer’s bag is...
– By means of an auscultation tube a hissing sound 
is heard. 
– Compressed air can also be used instead of 
politzer’s ba...
• Catheterisation 
31
• Procedure for Catheterisation 
32 
•Nose is anaesthetised 
•E Tube catheter passed along the floor of nose till it 
reac...
6. E.T. catheterization 
Air pushed into E.T. catheter by squeezing Politzer bag. 
Examiner hears by Toynbee auscultation ...
– Complications: 
• Injury to Eustachian tube opening 
• Bleeding from nose 
• Transmission of nasal & nasopharyngeal infe...
• Toynbee’s test 
– Uses negative pressure 
– Ask the patient to swallow while nose is pinched 
– Draws air from middle ea...
• Tympanometry (inflation-deflation test) 
– +Ve & -ve pressures are created in the external ear 
and the patient swallows...
Disorders of ET 
37
Tubal Blockage 
ACUTE TUBAL BLOCKAGE 
ABSORPTION OF ME GASES 
-VE PRESSURE IN ME 
RETRACTION OF TM 
TRANSUDATE IN ME/HAEMO...
• intrinsic 
• Extrinsic 
mechanical 
functional •Collapse 
both 
Block 
39
• Symptoms of tubal occlusion 
– Otalgia 
– Hearing loss 
– Popping sensation 
– Tinnitus 
– Disturbances of equilibrium 
...
• Clinical causes of ET obstruction 
– Upper respiratory tract infection 
– Allergy 
– Sinusitis 
– Nasal polypi 
– DNS 
–...
Adenoids 
• Adenoids cause tubal dysfunction by: 
– Mechanical obstruction of the tubal opening 
– Acting as reservoir for...
43
large adenoid blocking left et 
44
Cleft palate 
• Tubal dysfunction due to: 
– Abnormalities of torus tubaris 
– Tensor veli palatini doe not insert into th...
Down’s syndrome 
• Dysfunction due to: 
– Poor tone of tensor veli palatini 
– Abnormal shape of nasopharynx 
46
Barotrauma 
• Non suppurative condition resulting from failure 
of E Tube to maintain M Ear pressure at ambient 
atmospher...
Retraction Pockets & ET 
48
• Any obstruction in the ventilation pathway 
retraction pockets or atelectasis of tympanic 
membrane 
– Obstruction of Eu...
• Other changes 
– Thin atrophic TM 
– Cholesteatoma 
– Ossicular necrosis 
– Tympanosclerotic changes 
• Management 
– Re...
Patulous Eustachian Tube 
• ET is abnormally patent 
• Causes: 
– Idiopathic, rapid weight loss, pregnancy (esp 3rd 
trim)...
• Management 
– Acute cases Usually self-limiting 
– Weight gain & oral administration of KI 
– Long standing cases = caut...
EXAMINATION OF EUSTACHIAN TUBE 
Pharyngeal end of eustachian tube :posterior 
rhinoscopy, rigid nasal endoscope or flexib...
• Aetiologic causes of eustachian tube 
dysfunction assessed through: 
– Nasal examination 
– Endoscopy 
– Tests of allerg...
55
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Anatomy and physiology of eustachian tube

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Anatomy and physiology of the Eustation tube with mention on its disfunction

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Anatomy and physiology of eustachian tube

  1. 1. Anatomy & Physiology of Eustachian Tube Seema S 1
  2. 2. History • Bartolomeus Eustachius first described it as pharyngo-tympanic tube in 1562. • Antonio Valsalva named it Eustachian tube. 2
  3. 3. Embryology 3
  4. 4. Embryology • Develops from tubo-tympanic recess, derived from endoderm of 1st pharyngeal pouch. 4
  5. 5. 5
  6. 6. Anatomy 6
  7. 7. 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. 7
  8. 8. Angulation 8
  9. 9. Pharyngeal opening 9
  10. 10. Parts • Lateral 1/3 is bony • Medial 2/3 is fibro-cartilaginous. • Junction b/w 2 parts is isthmus, narrowest part of Eustachian Tube. 10
  11. 11. 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. 11
  12. 12. Anatomy • Lining epithelium: pseudo stratified ciliated columnar • Arterial supply: ascending pharyngeal & middle meningeal arteries • Venous drainage: pharyngeal & pterygoid venous plexus • Lymphatic drainage: retropharyngeal node 12
  13. 13. Anatomy Muscle attachments: 1. tensor veli palatini or dilator tubae 2. levator veli palatini 3. salpingopharyngeus 13
  14. 14. Nerve supply • Tubal mucosa – tympanic branch of cranial nerve IX • Tensor veli palatini - Mandibular branch of trigeminal 14 • Levator veli palatini Pharyngeal plexus • Salpingo pharygeus
  15. 15. 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. 15
  16. 16. Adult vs. Child (< 7 yr) 16
  17. 17. 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 17
  18. 18. 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 18
  19. 19. Physiology • Bony part is always open. • Fibro-cartilaginous part is closed at rest. • Opens on: 1. swallowing 2. yawning 3. sneezing 4. forceful inflation 19
  20. 20. 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. 20
  21. 21. E.T. opening 21
  22. 22. 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 22
  23. 23. 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 23
  24. 24. Functions 24
  25. 25. Conditions of Dysfunction 25
  26. 26. Tests for E.T. function 26
  27. 27. ET Function Tests • VALSALVA TEST – Principle: positive pressure in the nasopharynx causes air to enter the Eustachian tube 27
  28. 28. – 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 28
  29. 29. • 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” 29
  30. 30. – 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. 30
  31. 31. • Catheterisation 31
  32. 32. • Procedure for Catheterisation 32 •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)
  33. 33. 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. 33
  34. 34. – Complications: • Injury to Eustachian tube opening • Bleeding from nose • Transmission of nasal & nasopharyngeal infection into middle ear • Rupture of atrophic area of tympanic membrane 34
  35. 35. • 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. 35
  36. 36. • 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 36
  37. 37. Disorders of ET 37
  38. 38. Tubal Blockage ACUTE TUBAL BLOCKAGE ABSORPTION OF ME GASES -VE PRESSURE IN ME RETRACTION OF TM TRANSUDATE IN ME/HAEMORRHAGE PROLONGED TUBAL BLOCKAGE/DYSFUNCTION OME(THIN WATERY OR MUCOID DISCHARGE) ATELECTATIC EAR/PERFORATION RETRACTION POCKET/CHOLESTEATOMA EROSION OF INCUDOSTAPEDIAL JOINT 38
  39. 39. • intrinsic • Extrinsic mechanical functional •Collapse both Block 39
  40. 40. • 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 40
  41. 41. • 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 41
  42. 42. 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 42
  43. 43. 43
  44. 44. large adenoid blocking left et 44
  45. 45. 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 45
  46. 46. Down’s syndrome • Dysfunction due to: – Poor tone of tensor veli palatini – Abnormal shape of nasopharynx 46
  47. 47. 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 47
  48. 48. Retraction Pockets & ET 48
  49. 49. • 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 49
  50. 50. • Other changes – Thin atrophic TM – Cholesteatoma – Ossicular necrosis – Tympanosclerotic changes • Management – Repair of irreversible pathologic processes – Establishment of ventilation 50
  51. 51. 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 51
  52. 52. • Management – Acute cases Usually self-limiting – Weight gain & oral administration of KI – Long standing cases = cauterisation/ insertion of grommet 52
  53. 53. 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 53
  54. 54. • Aetiologic causes of eustachian tube dysfunction assessed through: – Nasal examination – Endoscopy – Tests of allergy – CT scan of temporal bones – MRI to exclude multiple sclerosis 54
  55. 55. 55

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