HISTORY OF EUSTACHEAN TUBE Anatomy / Physiology Dr T Balasubramanian drtbalu's otolaryngology online 1

Anatomy Eustachius first described the eustachean tube during the 16 th century Duverney (French Anatomist) was the first to realize the important role played by eustachean tube in middle ear ventilation Valsalva described the histology of eustachean tube and identified its bony and cartilagenous components drtbalu's otolaryngology online 2

Eber’s papyrus Eber’s papyrus is the oldest and most important medical manuscripts of ancient Egypt Breath of life passes through the right ear This papyrus contains detailed description of middle ear anatomy with reference to eustachean tube as a tube drtbalu's otolaryngology online 3

Alcmaeon of Croton Alcmaeon’s description was dated to about 500 BC He described that goats breath through their ears Singer noted that Alcmaeon recognized the existence of eustachean tube and auditory nerves Aristotle quotes Alcmaeon’s statement that goats breathe through their ears and also goes on to explain that he disagrees with it drtbalu's otolaryngology online 4

Quotes “From the cavity of stone like bone in which the auditory passage called concion ends a way perforates into the nasal cavity.” Eustachius Bartolommeo. “The passage which passes from the ear to the palate is called the aqueduct. This aqueduct is not only a canal it also makes room for passage of filth and humor.” “As in effect, the eustachean tube is divided by a muscle thanks to which whenever need arises this tube is able to enlarge” Valsalva drtbalu's otolaryngology online 5

Von Troltsch Von Troltsch was the first to identify that eustachean tube is not a complete cartilaginous structure. He suggested that the eustachean tube is closed externally by the presence of a membrane He also described the microscopic anatomy of the eustachean tube in great detail. He along with Salomon Moose took pains to study the physiological function of the eustachean tube drtbalu's otolaryngology online 6

Rich / Arnold Rice They were the first to dissect and expose the tensor and levator veli palatini They also identified the nerve supply to these muscles by dissecting in a live animal Rich also suggested that the 5 th cranial nerve supplied the tensor veli palatini muscle. He also observed that involvement of 5 th nerve is difficult to identify by observing palatal movements because this muscle exerts very little effect on the palate. drtbalu's otolaryngology online 7

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Functions of ET as per Toyenbee Mechanical protection against reflux of infected material from nasopharynx Prevention of retrograde propagation of vocalized sounds Mucociliary clearance of secretions from the middle ear cavity into the nasopharynx drtbalu's otolaryngology online 9

Politzer Was the first to identify that sound from a vibrating tuning fork when held in front of the nose found its way to the ear and the patient is able to perceive the sound This intensity of sound perception got increased during acts of swallowing as the patent eustachean tube conducts sound more efficiently. Politzer was able to demonstrate that the eustachean tube opened its pharyngeal end during the act of swallowing. Politzer was the first person to document the importance of ET in the middle ear physiology drtbalu's otolaryngology online 10

Toyenbee Suggested that the eustachean tube pharyngeal orifice nearly always remain open so that air inside the middle ear cavity is continuous with that of the nasopharynx He also suggested that it transported mucous secretions from the middle ear cavity into the nasopharynx on a continuing basis drtbalu's otolaryngology online 11

Jean Pierre Was the first to offer proof about the similarity of composition of mucous secretions from the lining membrane of eustachean tube and that of the mucosal lining of the middle ear cavity. He suggested that mucous secretion from the lining epithelium of eustachean tube played an important role in moderating the impact of foreign bodies that continuously pass from the oropharynx to the nasopharynx. drtbalu's otolaryngology online 12

Bonnafont’s theory Bonnafont theorized that gravity played a vital role in propelling fluid from the middle ear cavity via the eustachean tube into the nasopharynx. This concept was believed to be true for nearly two decades till Politzer described the now famous mucociliary clearance mechanism. It was Rich who described the role played by the ET muscles in its excretory function. drtbalu's otolaryngology online 13

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