The document summarizes the anatomy, physiology, and functional assessment of the Eustachian tube. It describes the embryological development of the Eustachian tube from the first pharyngeal pouch. Anatomically, it is a channel connecting the tympanic cavity to the nasopharynx that is composed of a bony portion, a cartilaginous portion, and muscles. Physiologically, its main functions are pressure regulation and clearance of the middle ear space. Eustachian tube dysfunction can result from various etiologies and is characterized by mucosal edema, reduced lateral wall motion, or obstructive lesions. Evaluation of Eustachian tube function involves history, physical exam including pneum

1. Eustachian tube
Anatomy, physiology and functional
assessment

2. embryology
 Develops from endoderm of first 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. anatomy
 Channel connecting tympanic cavity and
nasopharynx
 36mm in length ( 31- 38 mm)
 lumen of the Eustachian tube is roughly
triangular, measuring 2-3 mm vertically and 3-
4 mm horizontally.
 Lined by respiratory epithelium with goblet
cells and mucous glands
 Opens at about 1- 1.25 cm behind and a little
below posterior end of inferior turbinate

4. anatomy

5. anatomy
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

6. anatomy
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

7. Anatomy
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

8. anatomy

9. Endoscopic view of ET opening

10. anatomy
Ostmann fat pad
 contributing factor in closing the tube
 in the inferolateral aspect of the Eustachian
tube

11. physiology

12. functions
 Pressure regulation
 Clearance of middle ear space
 Protection of middle ear space from
nasopharyngeal pathogens and foreign
bodies

13. physiology

14. Eustachian tube dysfunction
Etiology
 upper respiratory infections
 Allergic rhinitis
 Chronic sinusitis
 Adenoid hypertrophy
 Tobacco smoke
 Reflux
 Cleft palate
 Radiation
 Nitrous oxide

15. ETD
Pathological events
 Mucosal edema
 Reduced lateral wall motion
 Obstructive lesion

16. ETD

17. Evaluation of ET
History
 Fullness of ears
 Pain and discomfort
 Hearing loss
 Tinnitus
 Dizziness

18. Evaluation of ET
Physical examination
 Retracted TM
 Middle ear effusion
 Pneumatic otoscopy
 Postnasal examination
 Endoscopic examination

19. Evaluaton of ET
 Valsalva maneuver
 Tonybee test
 Politzer test
 Sonotubometry

20. Thank u