Eustachian tube
Anatomy, physiology and functional assessment
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
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
anatomy
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
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
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
anatomy
Endoscopic view of ET opening
anatomy
Ostmann fat pad contributing factor in closing the tube in the inferolateral aspect of the Eustachian
tube
physiology
functions Pressure regulation
Clearance of middle ear space
Protection of middle ear space from nasopharyngeal pathogens and foreign bodies
physiology
Eustachian tube dysfunction
Etiology upper respiratory infections Allergic rhinitis Chronic sinusitis Adenoid hypertrophy Tobacco smoke Reflux Cleft palate Radiation Nitrous oxide
ETD
Pathological events Mucosal edema
Reduced lateral wall motion
Obstructive lesion
ETD
Evaluation of ET
History Fullness of ears
Pain and discomfort
Hearing loss
Tinnitus
Dizziness
Evaluation of ET
Physical examination Retracted TM Middle ear effusion Pneumatic otoscopy Postnasal examination Endoscopic examination
Evaluaton of ET
Valsalva maneuver Tonybee test Politzer test Sonotubometry
Thank u
Top Related