Mar 15, 2023
Eustachian tube (ET) is also called auditory tube or pharyngo tympanic tube. This tube connects the lateral part of nasopharynx to the anterior wall of the tympanic cavity (middle ear). ET is approximately 36mm in length. The lateral 1/3 of ET is bony. The medial 2/3 is cartilaginous. The narrowest part of ET is known as Isthmus. Isthmus is located on bony cartilaginous junction. The cartilaginous end of eustachian tube protrudes in nasopharynx called Torus Tubarius. ET is an angle of 45 degrees to the horizontal plane. Incase of neonates, this ET is always horizontal and tube length is always half of it. It is almost 16-18mm. Since the ET is shorter and horizontal in children, so the children are more prone to middle ear infection. ET has middle ear opening (5mmX2mm), has broader opening in the pharynx (8mmX3mm). The narrowest part (junction of bone and cartlage)is approximately 3mm
Keeps the eustachian tube in a closed position. The eustachian tube is closed at rest and that is because of Ostmanns Pad of Fat. The median fibres of tensor veli palatini is the main opener or dilator of the eustachain tube. Also known as dilator tubee. When tensor vili palatini contract, pulls the cartilage of eustchian tube anteriorly, that leads to opening of the eustachian tube. Secondary function of the levator vili palatini is opening of the eustachian tube.
Eustachian tube opens in the lateral wall of the nasopharynx, just behind the nasal cavity. Levator pili palatini and tensor vili palatini attached to the anterior surface. Tensor vili palatini contracts and open the eustachian tube. Tensor vili palatini goes down , takes a turn in pterygoid hamulus and attached in the centre (soft palate). Patients of cleft palate has ET dysfunction that lead to middle ear disorders because in cleft palate the muscles wont able to meet in the centre.
Also read: Anatomy of Middle Ear - NEET PG ENT
This catheter has soft rounded ending with a bulge. On the other side the ring is present . The ring helps to identify the side of the turn. Insert the ET cathether straight into the nasal cavity, pass it along into the nasopharynx and than rotate it medially and pull it back. The turn will engage behind the nasal septum. Rotate it by 180 degrees and enter into the eustachian tube. Attach the politizer bag and blow open the ET.
In perforated tympanic membrane instead of dye can also instill saccharine . Saccharine has sweet taste, it will come in the throat. Can also use dye ( methylene blue)
When the eustachian tube is open at rest. The patulous eustachian tube will lead to autophony. The patient hear his only voice very loud. Patulous eustachian tube can happen incase of rapid weight loss or in pregnancy. Treatment- Scar the eustachian tube or inject fat in the eustachian tube.
Sono means sound, tubometry is to check the eustachian tube function. This is the latest investigation. Sound is given in the nose, which reach in the middle ear and sound source can be picked up by a probe in the EAC.
The most disorders of the eustachian tube are because of the obstruction of the eustachian tube. Obstruction can be due to mass, polyp, malignancy. In these condtions, treat the cause. However sometimes, because of the repeated infections, euctachian tube may undergo scarring, fibrosis. Because of that eustachian tube may undergo stenosis. In these chronic eustachian tube disoredrs, now a days eustachian tube balloon dialation is done.
For more interesting and informative articles like this, download the PrepLadder app now.
Get access to all the essential resources required to ace your medical exam Preparation. Stay updated with the latest news and developments in the medical exam, improve your Medical Exam preparation, and turn your dreams into a reality!
The most popular search terms used by aspirants