1. The Eustachian tube connects the middle ear cavity to the nasopharynx and equalizes pressure on either side of the eardrum. It has bony, cartilaginous, and muscular components. 2. The Eustachian tube opens during swallowing, yawning, and sneezing due to the contraction of muscles like the tensor veli palatini. This allows ventilation and drainage of the middle ear. 3. Disorders of the Eustachian tube include blockage, which can cause otitis media, as well as barotrauma from pressure changes like scuba diving. Evaluation involves tests like Valsalva maneuver and tympanometry

1. EUSTACHIAN TUBE
ANATOMY AND
PHYSIOLOGY
-BY DR SANGLAGNA JANA

2. • BARTOLOMEUS EUSTACHIUS first
described it as pharyngotympanic tube in
1562
• ANTONIO VALSALVA later named it
Eustachian tube

3. EMBRYOLOGY
• The Eustachian tube develops from
the TUBOTYMPANIC RECESS
• Derived from endoderm of 1st
pharyngeal pouch
• Distal portion- forms middle ear
cavity
• Proximal portion-forms the
eustachian tube

4. ANATOMY
• 36 mm in adults
• Directed downwards from middle ear
• Angulation from horizontal – 45 degree
• Turns forwards and medially
• Has bony and cartilaginous parts

5. • Enters the
nasopharynx
• 1-1.25 cm behind
and little below the
posterior end of
inferior turbinate

6. • Lateral 1/3rd –bony
• 12mm , widest at oval shaped orifice
• Goes – squamous and petrous part of
temporal bone
• Tapers at isthmus – diameter of 0.5mm or less

7. RELATIONS OF BONY PART OF EUSTACHIAN
TUBE AND CLINICAL IMPORTANCE
• Roof- a thin plate of bone, separating tube from the tensor tympani
muscle above
• Medially – carotid canal , which can impinge on the tube
• Due to anatomical variation , sometimes dehiscence of the right internal
carotid artery at the level of the eustachian tube can cause PULSATILE
TINNITUS

9. • Medial 2/3rd –cartilaginous
• 24mm long
• Sits in groove – petrous part of temporal
bone and greater wing of sphenoid
• Apex –attached with isthmus of bony portion
• Medial end- wider ,protruding towards
nasopharynx
• Lying directly under mucosa to form TORUS
TUBARIUS

10. • Upper border- cartilage resembles inverted j shape
• Forms longer – medial cartilaginous lamina
(posteromedial wall) at the back
• Forms shorter- lateral cartilaginous lamina
(anterolateral wall) at the front , comprising
cartilaginous and fibrous tissue
• Medial and lateral lamina is separated by elastin
hinge
• OSTMANN’S FAT PAD lies anterolaterally

11. • Opening – triangular
• Surrounded above and behind
by TORUS TUBARIUS
• Behind TORUS is the
PHARYNGEAL RECESS or
FOSSA OF ROSENMULLER

12. HISTOLOGY
• Tube lined by-respiratory mucosa –
pseudo stratified ciliated epithellium
• Contains- Goblet and Mucous cells
• Nasopharyngeal end- mucosa truly
respiratory
• Tympanic end- Goblet cells and glands
decreases, ciliary epithelium less
profuse

13. MUSCLES ATTACHED TO EUSTACHIAN TUBE
1. Tensor veli palatini –
Arises from – bony wall of scaphoid fossa ,
along whole length of lateral cartilaginous
lamina
Muscle descends , converges to short
tendon
Turns medially around pterygoid Hamulus
Spreads out to meet fibres of other side in
midline raphe(palantine aponeurosis)

14. • Function of tensor veli palatini-
Tenses palatine aponeurosis; Opens
pharyngeal opening of auditory tube
(during swallowing)
• Innervation-
Nerve to medial pterygoid (of mandibular
nerve (CN V3))
• Blood supply-
Greater palatine artery (maxillary artery),
ascending palatine artery (facial artery)

15. 2. Levator veli palatini-
Arises from - lower surface of cartilaginous
tube and apex of petrous bone, fascia of
upper carotid sheath
Lies inferior to tube, then
Crosses to medial side , spreads into soft
palate

16. • Function of levator veli palatini-
elevates the soft palate during swallowing, preventing food to enter nasopharynx
• Innervation-
pharyngeal plexus which is supplied by the vagus nerve (CN X).

17. 3. Tensor tympani-
Arises from- cartilaginous part of Eustachian
tube and the adjacent great wing of sphenoid
Passes through its own canal, and ends in
the tympanic cavity as a slim tendon , connects
to the handle of the malleus.
The tendon makes a sharp bend around
the PROCESSUS COCHLEARIFORMIS, part
of the wall of its cavity, before it joins with the
handle of malleus

18. • Function of tensor tympani-
Dampens noise produced by chewing.
When tensed, pulls the malleus medially, tenses TM and dampens vibration in
ear ossicles, reducing the perceived amplitude of sounds.
• Innervation –
tensor tympani nerve, a branch of the mandibular branch of the trigeminal nerve
• Blood supply-
Middle meningeal artery via the superior tympanic branch

19. CLINICAL IMPORTANCE OF TENSOR TYMPANI
• In HYPERACUSIS, increased activity develops in tensor tympani muscle as part of
the startle response to some sounds.
• This lowered reflex threshold for tensor tympani contraction is activated by the
perception/anticipation of loud sound, and is called tonic tensor tympanic
syndrome (TTTS).
• In some people with HYPERACUSIS, the tensor tympani muscle can contract just by
thinking about a loud sound.
• Following exposure to intolerable sounds, this contraction of the tensor tympani
muscle tightens the ear drum, which can lead to the symptoms of ear pain/a fluttering
sensation/a sensation of fullness in the ear (in the absence of any middle or inner
ear pathology)

20. 4. Salpingopharyngeus-
• Arises from – inferior part of the
cartilaginous tube
Near the pharyngeal opening
Descends to blend with the
palatopharyngeus

21. • Function of salpingopharyngeus-
Elevates pharynx and larynx at swallowing
Opens or pulls on TORUS TUBARIUS for equalization of pressure
• Innervation –
Vagus nerve via the pharyngeal plexus
• Blood supply-
Supplied by ascending pharyngeal artery

22. • Salpinopharyngeal fold-
The paired slender muscles
creates vertical ridges of mucous
membrane in the posterior
pharyngeal wall
Descending from the medial ends of
the Eustachian tubes (torus)
Containing the salpingopharyngeus
muscle

23. CLINICAL IMPORTANCE OF SALPINGOPHARYNGEAL FOLD
• Presence of SPF hypertrophy independently added to severity of obstruction, attributing to
lateral collapse at upper retropalatal level and significantly increasing AHI.
• Grade 0 being normal anatomy,
• Grade 1 being hypertrophy causing partial obstruction and
• Grade 2 being hypertrophy causing complete obstruction of lateral pharyngeal wall
It is thus advised to consider the grade of SPF hypertrophy while surgically planning the
management of patients with OSA
ORIGINAL ARTICLEA Novel Grading System for Salpingopharyngeal FoldHypertrophy in Obstructive Sleep ApnoeaVikas K. Agrawal1Swati Kodur1Raghav Hira Jha https://doi.org/10.1007/s12070-018-1513-2

24. ENDOSCOPIC ANATOMY
• Medial end forms tubal elevation
called torus tubarius
• Lymphoid collection over torus is
called GERLACH’S TUBAL TONSIL
• Postero superior to torus is FOSSA
OF ROSENMULLER

25. ADULT VS INFANT EUSTACHIAN TUBE

26. PHYSIOLOGY
• Bony part is always open
• Fibrocartilaginous part is closed at rest and only opens at
1. Swallowing
2. Yawning
3. Sneezing
4. Forceful inflation

27. • Opens actively by contraction of
TENSOR VELI PALATINI
• Opens passively by contraction of
LEVATOR VELI PALATINI
• Closes by elastic recoil of ELASTIN
HINGE with the deforming force of
OSTMANN’S FAT PAD

28. FUNCTIONS OF EUSTACHIAN TUBE
• Ventilation
• Maintenance of atmospheric pressure in middle ear for normal hearing
• Drainage of middle ear secretions into nasopharynx
by muco-ciliary clearance
pumping action of ET
presence of intraluminal surface tension

29. FUNCTIONS OF EUSTACHIAN TUBE
• Protection of middle ear from-
Ascending nasopharyngeal secretions
Pressure fluctuations
Loud sound coming through pharynx

30. EVALUATION OF EUSTACHIAN TUBE
Through history-
Fullness of ears
Pain and discomfort
Hearing loss
Tinnitus
Dizziness
Through physical examination-
Retraction of TM
Middle ear effusion
Pneumatic otoscopy
Postnasal examination
Endoscopic examination
Valsalva maneuver
Toynbee test
Catherisation
Politzer test
Sonotubometry
Frenzels maneuver

31. EXAMINATION OF EUSTACHIAN TUBE
• Endoscopic examination-
Pharyngeal end is examined
• Otoscopic examination-
Tympanic end is examined

32. TESTS FOR E.T.FUNCTION
• Valsalva test
Principle: positive pressure in the nasopharynx causes air to enter the tube

33. • Tympanic membrane perforation –
produces hissing sound
• Discharge in middle ear – cracking sound
Contraindications-
Atrophic scar of tympanic membrane
Infection of nose and nasopharynx

34. • Frenzels maneuver-
Patient is asked to close nose and mouth ,and move tongue up against palate
against a closed glottis
Clicking sounds can be heard, while noting the movement of TM
TESTS FOR E.T.FUNCTION

35. TESTS FOR E.T.FUNCTION
• Politzer test
Olive shaped tip of the politzer’s bag
is introduced in patient’s nostril
Other nostril closed
Bag compressed while the patient
swallows or says “ik,ik,ik”
Hissing sound heard on auscultation
Therapeutic use- to ventilate middle
ear

36. TESTS FOR E.T.FUNCTION
• Catherisation
Nose anesthesized
Catheter passed along floor of nose till it reaches naso
pharynx
Rotated 90 degrees medially
Pulled back till posterior border of nasal septum is
engaged
Rotated 180 degrees laterally- tip lies against tubular
opening
Politzer bag connected, air insufflated, entry of air in
middle ear verified(lateral bulging of TM)

37. • Catheterization contd:
Examiner hears by Toynbee auscultation tube
Blowing sound- normal patency
Bubbling sound- middle ear fluid
Whistling sound- partial E.T.obstruction
No sound- complete obstruction

38. • Catheterization complications-
Injury to Eustachian tube opening
Bleeding from nose
Transmission of nose and nasopharyngeal infections to middle ear
Rupture of atrophic area of TM

39. • Toynbee’s test-
Principle: uses negative pressure
Patient is asked to pinch nose and swallow
Air is drawn out of middle ear to
nasopharynx causing inward movement of
tympanic membrane
• Tympanometry (inflation-deflation test)-
-ve and +ve pressures created in external
ear while patient swallows repeatedly

40. • Tympanometry contd:
Principle: Introduces a pure tone into
ear canal through 3 probes
Manometre pump which varies the
pressure gradient against TM
Speaker introduces 220 Hz probe
tone
Microphone measures loudness in ear
canal

42. • Radiological test-
Plain CT scan and MRI or modified with contrast enhanced radiographs and
scintigraphy

43. • Saccharin or methylene blue test-

44. • Sonotubometry –
Tells the duration for which the tube remains open
Tone is heard louder if tube is patent

45. DISORDERS OF EUSTACHIAN TUBE
A. Tubal blockage / occlusion:
Symptoms –
1. Otalgia
2. Hearing loss
3. Popping sensation
4. Tinnitus
5. Disturbances in equilibrium
Signs–
1. Retracted TM
2. Congestion along handle of
malleus and pars tensa
3. Transudate behind TM

47. • Causes of Eustachian tube
obstruction-
1. Upper respiratory tract infection
2. Allergy
3. Sinusitis
4. Nasal polyp
5. Deviated nasal septum
6. Hypertrophic adenoids
7. Nasopharyngeal mass/tumor
8. Cleft palate
9. Submucous cleft palate
10. Down’s syndrome

48. Adenoids:
cause tubal dysfunction by-
• Mechanical obstruction of tubal opening
• Acting as reservoir of pathogens
• Inflammtory mediators in allergy cause tubal block
Adenoid can cause otitis media with effusion or
recurrent acute otitis media
Adenoidectomy is mainstay
DISORDERS OF EUSTACHIAN TUBE

49. DISORDERS OF EUSTACHIAN TUBE
Cleft palate:
Tubal dysfunction due to-
Abnormalities of torus tubarius
 Tensor veli palatini does not insert into the
torus tubarius
Otitis media with effusion is common in these
cases

50. DISORDERS OF EUSTACHIAN TUBE
Down’s syndrome:
Dysfunction due to-
 poor tone of tensor veli palatini
Abnormal shape of nasopharynx

51. DISORDERS OF EUSTACHIAN TUBE
B. Barotrauma:
Non suppurative condition resulting from failure of Eustachian tube to maintain
middle ear pressure at ambient atmospheric level
Cause –
• Rapid descent of flight
• Underwater diving
• Compression in pressure chamber

52. When atmospheric pressure >> middle ear pressure
By critical pressure of 90 mmHg (13 kPa) and equivalent depth of
approximately 1.3m (3.9 ft)
Eustachian tube gets locked in
Causing a negative pressure in middle ear
Results in – retraction of tympanic membrane ,
transudation / hemorrhage

53. DISORDERS OF EUSTACHIAN TUBE
F. Retraction pockets:
• Obstruction in ventilation pathway
Atelectasis of TM
• Obstruction in aditus
Cholesterol granuloma
Mucoid discharge in MAC

54. • Other changes-
Thin atrophic TM
Cholesteatoma
Ossicular necrosis
Tympanosclerotic changes

55. DISORDERS OF EUSTACHIAN TUBE
• Patulous Eustachian
tube
Causes-
i. Idiopathic
ii. Rapid Weight loss
iii. Pregnancy
iv. Multiple sclerosis
Complaint - Autophony

56. THANK YOU
Referance – Scott Brown
Dhingra
Hazarika