Eustachian Tube Function, Anatomy & Diagram | Body Maps Your message has been sent. OK We're sorry, an error occurred. We are unable to collect your feedback at this time. However, your feedback is important to us. Please try again later. Close Pharyngotympanic tube The eustachian tube is a canal that connects the middle ear to the nasopharynx, which consists of the upper throat and the back of the nasal cavity. It controls the pressure within the middle ear, making it equal with the air pressure outside the body. Most of the time the eustachian tube is closed, opening only during activities such as yawning, swallowing, and chewing, to allow air through the passage between the middle ear and nasopharynx. When atmospheric pressure changes rapidly, causing a sudden feeling of blockage in the ear (such as during airplane travel), these activities can be done on purpose to open the tube and equalize the pressure within the middle ear. When the eustachian tube will not open enough to equalize pressure, symptoms such as discomfort, dizziness, or ringing in the ear may result.

Visual examination of the eardrum with a lighted scope helps to determine if the cause is inflammation, swelling, or fluid in the ear. Conditions such as nasal congestion, infection of the ear or sinus, or allergies may cause these symptoms and lead to eustachian tube problems. These causes can often be treated with decongestant medication or antibiotics, but in severe cases, surgery may be necessary. Ear Anatomy | Inside the ear | 3D Human Ear animation video | Biology | Elearnin - YouTube Ear Anatomy | Inside the ear | 3D Human Ear animation video | Biology | Elearnin Want to watch this again later? Sign in to add this video to a playlist. Need to report the video? Sign in to report inappropriate content. The interactive transcript could not be loaded. Loading... Rating is available when the video has been rented. This feature is not available right now. Please try again later. Published on Jun 4, 2013 Ear Anatomy | Inside the ear | 3D Human Ear animation video | Biology | Elearnin Ear is that part of the human body that detects sound from the environment and delivers it to the brain.

With the help of a ear, humans have the ability to locate the sources of sound. Apart from just being a receiver of sound, it also plays a major role in maintaining a proper balance and position of the body. So as per the laws of science, sound is actually caused when the air molecules are set into vibration and one can hear the sound when the ear picks up or feels these vibrations or sound waves. There are nine main parts of the ear that include the pinna, the ear canal, the ear drum, the hammer, anvil, stirrup, cochlea , Eustachian tube and the auditory nerve. The pinna, also known as the auricle, is the visible portion of the ear that is externally seen. This helps in locating sound sources and directs the sound into it. This does not play any role in maintaining the balance of sound that is heard. The ear canal is a tube like pipeline, that connects the outside of the ear to the ear drum. The ear drum is in the middle ear, which vibrates on receiving sound waves. The hammer on receiving the vibrations from the eardrum, sends them to the anvil that inturn passes them to the stirrup and these are then passed to the inner ear.

The inner ear consists of the cochlea and a liquid. The cochlea is a shell-like structure. The Eustachian tube controls the amount of pressure in the ear. The auditory nerve carries the sound to the brain and it is the brain that interprets the sound. The ear together with the brain , controls the balance of the body. All the movements are controlled by this balance and also with the help of muscles. The liquid in the inner ear that we mentioned earlier, is actually responsible for the balance. The liquid in the ear moves along in sync with the physical movement of the body and thus, sending information to the brain on how the body is actually moving at any given instance. The earlobe is the soft lower part of the external ear and this does not have any firmness nor any elasticity. It contains a cartilage and has a large amount of blood supply that provides warmth to the ears and hence aids in the overall balance process.

Category Eustachian Tube Function: Overview, Embryology of the Eustachian Tube, Anatomy of the Eustachian Tube Embryology of the Eustachian Tube Overview Overview The eustachian tube (pharyngotympanic tube) connects the middle ear cavity with the nasopharynx. It aerates the middle ear system and clears mucus from the middle ear into the nasopharynx. Opening and closing functions of the eustachian tube are physiologically and pathologically important. Normal opening of the eustachian tube equalizes atmospheric pressure in the middle ear; closing of the eustachian tube protects the middle ear from unwanted pressure fluctuations and loud sounds. Mucociliary clearance drains mucus away from the middle ear into the nasopharynx, thus preventing infection from ascending to the middle ear. Anatomy of the ear. Abnormal or impaired eustachian tube functions (ie, impaired opening or closing, defective mucociliary clearance) may cause pathological changes in the middle ear. This in turn can lead to hearing loss and other complications of otitis media . These pathological changes include recurrent acute otitis media and otitis media with effusion.

Chronic retraction of the tympanic membrane may also lead to middle ear atelectasis and subsequent adhesive otitis media. A retraction pocket of the tympanic membrane secondary to chronic eustachian tube dysfunction may eventually evolve into cholesteatoma and potentially serious complications. Next: Embryology of the Eustachian Tube The eustachian tube lumen develops in the embryo by the lateral extension of the endoderm of the first pharyngeal pouch as it touches the inner surface of the ectoderm of the first branchial cleft. During this process, the distal portion of the pouch expands, forming the tubotympanic recess, which will later evolve into the middle ear cavity. The proximal portion narrows to form the eustachian tube. This process takes place during the first 10 weeks of gestation. The cartilage and muscles of the eustachian tube develop from the surrounding mesoderm during the ensuing weeks. The levator veli palatini and the tensor veli palatini muscles seem to develop earlier than the cartilage and glandular tissue.

The cartilaginous portion of the tube elongates during the middle and third trimester until it reaches approximately 13 mm in length at term. Other morphologic changes also occur during that time with further development of the glandular structures and folding of the epithelium. As the skull base grows down, the angle of the eustachian tube changes gradually from horizontal to oblique. This process continues after birth and well into adulthood. Previous Anatomy of the Eustachian Tube Cartilaginous and bony framework The eustachian tube in the adult is approximately 36 mm long and is directed downward, forward, and medially from the middle ear. It consists of 2 portions, a lateral third (12 mm), which is a bony portion arising from the anterior wall of the tympanic cavity, and a medial two thirds (24 mm), which is a fibrocartilaginous portion entering the nasopharynx. The tube opens about 1.25 cm behind and slightly below the posterior end of the inferior turbinate. The bony portion is widest at its tympanic end.

It passes through the squamous and petrous portions of the temporal bone but narrows gradually to the isthmus, which is the narrowest part of the eustachian tube. The cartilaginous portion consists of a plate of cartilage posteromedially. The cartilage bends forward to form a short flange. The rest of the anterolateral wall is formed by fibrous tissue. The apex or lateral end of the cartilaginous part joins the bony portion at the isthmus; the wider medial end lies under the mucosa of the nasopharynx and raises the mucosa to form the tubal elevation (torus tubarius). Just behind this elevation is a recess called the fossa of Rosenmüller, which is a common site of origin for nasopharyngeal carcinoma and occult primary tumors. The cartilaginous eustachian tube is attached to the skull base in a groove between the petrous part of the temporal bone and the greater wing of the sphenoid. The lumen of the eustachian tube is roughly triangular, measuring 2-3 mm vertically and 3-4 mm horizontally.

The bony portion is always open; the fibrocartilaginous portion is closed at rest and opens only on swallowing, yawning, or forceful inflation. The eustachian tube in infants measures approximately 18 mm in length. It is about half the size of the adult eustachian tube and is generally more horizontal and less angulated. The bony portion is relatively longer and wider in diameter, the nasopharyngeal end of the cartilaginous portion lies more inferiorly. At its nasopharyngeal opening, the eustachian tube is lined by respiratory epithelium that includes columnar ciliated cells, goblet cells, and mucous glands. The respiratory epithelium blends with the middle ear mucosa in the bony portion of the tube. A recent study Ozturk et al, [ 1 ] found that the length of the mucosal surface of the posterior wall of the eustachian tube was longer than the anterior wall and, in pediatric specimens, that the posterior wall had more mucosal folds (microturbinates) than adult specimens.

They concluded that these microturbinates may provide important protection and clearance functions for children and play a role in the pathogenesis of eustachian tube dysfunction (see Eustachian Tube Dysfunction). Ostmann fat pad This fat pad is located in the inferolateral aspect of the eustachian tube and is thought to be an important contributing factor in closing the tube. It is also quite likely to contribute in the protection of the eustachian tube and the middle ear from retrograde flow of nasopharyngeal secretions. Previous Relations of the Eustachian Tube Muscles The muscles of the eustachian tube system help open and close the tube, thus allowing it to perform its function. These muscles are the (1) tensor veli palatini, (2) levator veli palatini, (3) salpingopharyngeus, and (4) tensor tympani. The tensor veli palatini muscle originates from the bony wall of the scaphoid fossa and from the whole length of the short cartilaginous flange that forms the upper portion of the front wall of the cartilaginous tube.

The muscle runs downward, converging into a short tendon that turns medially around the pterygoid hamulus. It then fans out within the soft palate and mingles with the fibers from the opposite side in the midline raphe. The tensor veli palatini separates the eustachian tube from the otic ganglion, the mandibular nerve and its branches, the chorda tympani, and the middle meningeal artery. The salpingopharyngeus is a delicate muscle that is attached to the pharyngeal end of the eustachian tube and blends with the palatopharyngeus muscle downward. The levator veli palatini has 2 origins: the lower surface of the cartilaginous tube and the lower surface of the petrous bone. At first, the levator is inferior to the tube; it then crosses to the medial side and merges into the soft palate. Blood vessels The arterial supply of the eustachian tube is derived from the ascending pharyngeal and middle meningeal arteries. The venous drainage is carried to the pharyngeal and pterygoid plexus of veins.

The lymphatics drain into the retropharyngeal lymph nodes. Ozturk et al (2012) studied the anatomical relation between the eustachian tube and petrous portion of the internal carotid artery (ICA). [ 2 ] They found that the junctional part of the eustachian tube may be a safe landmark to identify and protect the ICA. Knowledge of the anatomical relationships of the eustachian tube with other surgical and radiological landmarks is definitely useful during endoscopic endonasal procedures and cranial base surgery. Nerves The pharyngeal branch of the sphenopalatine ganglion derived from the maxillary nerve (V2) supplies the ostium. The nervus spinosus derived from the mandibular nerve (V3) supplies the cartilaginous part, and the tympanic plexus derived from the glossopharyngeal nerve supplies the bony portion of the eustachian tube.

Previous Three Physiologic Functions of the Eustachian Tube The physiologic functions of the eustachian are as follows: Ventilation or pressure regulation of the middle ear Protection of the middle ear from nasopharyngeal secretions and sound pressures Clearance or drainage of middle ear secretions into the nasopharynx Ventilation or pressure regulation The normal eustachian tube at rest is collapsed, with perhaps slight negative middle ear pressure. Repeated opening of the eustachian tube actively maintains normal atmospheric pressure. The eustachian tube opens upon swallowing or yawning by contraction of the tensor veli palatini muscle. Defective tensor veli palatini muscle function in cleft palate results in eustachian tube dysfunction. The role of the levator veli palatini muscle is unclear. Its contribution in opening the eustachian tube has been questioned. Eustachian tube ventilatory function is less efficient in children than in adults. In addition, repeated upper respiratory tract infections and enlarged adenoids in children further contribute to the increased incidence of middle ear disease in children. However, as children grow, eustachian tube function improves as evidenced by the reduced frequency of otitis media from infancy to maturity.

Normally, the eustachian tube opens frequently, stably maintaining the middle ear pressure between +50 mm and -50 mm H2 O. However, pressures above and below this range do not necessarily indicate middle ear disease. About 1 mL of air or gas may be absorbed from the middle ear in 24 hours. The mastoid cell system is thought to function as a gas reservoir for the middle ear. Protection The eustachian tube is closed at rest. Sudden loud sounds are thus dampened before reaching the middle ear through the nasopharynx. Patulous eustachian tube is an abnormal but not uncommon condition in which the tube is abnormally patent. The patient often complains about echoing when he or she talks (autophony), as well as ear fullness. Rapid weight loss may lead to decreased size of the Ostmann fat pad, which is thought to contribute to this condition. The eustachian tube drains normal secretions of the middle ear by the mucociliary transport system and by repeated active tubal opening and closing, which allows secretions to drain into the nasopharynx.

A derangement in the closed middle ear system, such as tympanic membrane perforation or after mastoid surgery, sometimes results in reflux of nasopharyngeal secretions into the tube and can cause otorrhea. Similarly, forceful nose blowing creates high nasopharyngeal pressure and may force nasopharyngeal secretions into the middle ear. Laryngopharyngeal reflux (LPR) was recently implicated in the etiology of otitis media with effusion (OME). Al-Saab et al (2008) demonstrated the presence of pepsinogen in 84% of middle ear effusions (MEEs) at concentrations 1.86 to 12.5 times higher than that of serum. [ 3 ] Conversely, a relative negative middle ear pressure, as occurs in aircraft or scuba diving descent, may lock the eustachian tube. This leads to stagnation of secretions, and effusion collects in the middle ear as otitic barotrauma evolves. Inflation of the eustachian tube by the Valsalva maneuver or by politzerization can break the negative pressure in the middle ear and clears the effusion.

The middle ear is also protected by the local immunologic defense of the respiratory epithelium of the eustachian tube, as well as its mucociliary defense (clearance). A pulmonary immunoreactive surfactant protein has been isolated from the middle ears of animals and humans. It is thought to have the same protective function in the middle ear. Clearance or drainage Drainage of secretions and occasional foreign material from the middle ear is achieved by the mucociliary system of the eustachian tube and the middle-ear mucosa and muscular clearance of the eustachian tube, as well as surface tension within the tube lumen. The flask model proposed by Bluestone and his colleagues helps to better explain the role of the anatomic configuration of the eustachian tube in the protection and drainage of the middle ear. [ 4 ] In this model, the eustachian tube and middle ear system is likened to a flask with a long narrow neck. The mouth of the flask represents the nasopharyngeal end, the narrow neck represents the isthmus, and the middle ear and mastoid gas cell system represents the body of the flask.

Fluid flow through the neck depends on the pressure at either end, the radius and length of the neck, and the viscosity of the liquid. When a small amount of liquid is instilled into the mouth of the flask, the liquid flow stops somewhere in the narrow neck due to the narrow diameter of the neck and the relative positive air pressure in the chamber of the flask. However, this does not take into consideration the dynamic role of the tensor veli palatini muscle in actively opening the nasopharyngeal orifice of the eustachian tube. Previous Next: Eustachian Tube Function Tests A functional and patent eustachian tube is necessary for ideal middle ear sound mechanics. A fully patent eustachian tube may not necessarily have perfect functioning, as is the case with the patulous eustachian tube or with mucociliary abnormalities. Testing of both eustachian tube patency and function are therefore important. Pneumatic otoscopy Permeatal examination of the tympanic membrane assesses the patency and perhaps the function of the tube. A normal appearing tympanic membrane usually indicates a normally functioning eustachian tube, although this does not preclude the possibility of a patulous tube.

Otoscopic evidence of tympanic membrane retraction or fluid in the middle ear indicates eustachian tube dysfunction but cannot be used to differentiate between functional impairment and mechanical obstruction of the tube. Normal tympanic membrane mobility on pneumatic otoscopy (siegalization) indicates good patency of the eustachian tube. Nasopharyngoscopy Nasopharyngoscopy by posterior rhinoscopic mirror examination or more accurately by fiberoptic endoscope helps visualization of any mass (eg, adenoids, soft tissue growth in the nasopharynx) that may be obstructing the pharyngeal end of the eustachian tube. Attempts have been made to assess eustachian tube function with the help of nasopharyngoscopy. Yagi and colleagues evaluated the patency of the eustachian tube using a fiberoptic endoscope and a photoelectric device (phototubometry). [ 5 ] Using videoendoscopy of the ear, Poe and colleagues assessed tubal function in adults and observed various disease processes such as inflammation of the tube and patulous dysfunction. This method has been gaining popularity in the assessment of patients suspected to have eustachian tube dysfunction.

Tympanometry Measuring middle ear pressure with an electroacoustic impedance meter helps to assess eustachian tube function. High negative middle ear pressure (>-100 daPa) indicates eustachian tube dysfunction. High negative pressures may be seen in individuals with normal hearing; however, a nearly normal middle ear pressure may be associated with hearing loss. In the presence of tympanic membrane perforation, the air passes into the middle ear resulting in a large canal volume on tympanometry. Imaging With the recent development of advanced imaging technology, studies have been used to better define the anatomy and pathology of the eustachian tube. MRI has been used to visualize the eustachian tube and to assess its anatomy and pathology in patients with nasopharyngeal carcinoma. Moreover, MRI has been used in experimental animal models to evaluate middle ear inflammation. It has more accurately been also used to assess the effect of experimentally induced functional obstruction of the eustachian tube by botulinum toxin A on the middle ear. CT has also been used to assess the tube in normal individuals, in patients with patulous eustachian tube, and in otitis media. It has also been used in studying eustachian tube clearance.

Fluoroscopy with contrast provides dynamic evaluation of mucociliary clearance. Yoshioka et al (2013) studied the movement of the eustachian tube during sniffing in patients with patulous tube using a 320-Row Area Detector CT scanner. [ 6 ] They demonstrated various patterns of eustachian tube closure during sniffing in these patients. This method may be useful for evaluating different types of eustachian tube dysfunction. A prospective study by Tarabichi and Najmi indicated that in most persons with healthy ears, temporal bone CT scans performed during the Valsalva maneuver can visualize the distal third of the eustachian tube lumen, suggesting that this imaging strategy could help to localize disorders in patients with symptoms of eustachian tube obstruction. The study was performed on 38 patients (76 ears), with the distal third of the lumen visualized in 71 ears (93%) and the entire lumen visualized in 27 ears (36%).

[ 7 ] Eustachian tube catheterization Catheterization of the eustachian tube with a curved metal cannula via the transnasal approach has been used to assess tubal function for more than 100 years. It can be done blindly, with the help of a nasopharyngoscope, or transorally with a 90° telescope. The catheter is passed along the floor of the nose until it touches the posterior wall of the nasopharynx. The catheter is then rotated 90° medially and pulled forward until it impinges on the posterior free part of the nasal septum. The catheter is then rotated 180° laterally, so that its tip lies at the nasopharyngeal opening of the eustachian tube. A Politzer bag is attached to the outer end of the catheter, and an auscultation tube with 2 ear tips is used with one tip in the patient's ear and the other in the examiner's ear. Air is pushed into the catheter by means of the Politzer bag.

The examiner hears the rush of air as it passes through the catheter into the eustachian tube and then into the middle ear. Successful transferring of applied positive pressure from the proximal end of the cannula into the middle ear suggests tubal patency. Normal blowing sounds mean a patent eustachian tube and bubbling indicates middle ear fluid. Whistling suggests partial eustachian tube obstruction while absence of sounds indicates complete obstruction or failed catheterization. Valsalva and Politzer tests In the Valsalva test, the eustachian tube and middle ear are inflated by a forced expiration with the mouth closed and the nose pinched by the thumb and forefinger. The effect of high positive nasopharyngeal pressures at the proximal end of the eustachian tube system can be evaluated qualitatively. When the tympanic membrane is intact, the overpressure in the middle ear can be observed by otoscopy as a bulging tympanic membrane. When the tympanic membrane is perforated, the sound of the air escaping from the middle ear can be heard with a stethoscope or with the Toynbee tube.

The Politzer test is similar to the Valsalva test, but instead of positive nasopharyngeal pressure being generated by the patient, the nasopharynx is passively inflated. This is achieved by compressing one nostril into which the end of a rubber tube attached to an air bag has been inserted while compressing the opposite nostril by finger pressure. The subject is asked to swallow or to elevate the soft palate by repeating the letter "k." Both the Valsalva and Politzer tests are outdated and rarely used clinically for assessment of eustachian tube function. These maneuvers may be more beneficial in the management of some patients. Nevertheless, the efficacy of these procedures for treatment of middle ear effusion is controversial, and they are not without potential risks. The author has encountered a case of meningitis following Politzerization for the treatment of otitis media with effusion in an otherwise healthy elderly man. Toynbee test This test is considered more reliable than the previous 2 in the assessment of eustachian tube function. On closed nose swallowing, negative middle ear pressure develops in healthy persons. In an intact tympanic membrane, pneumatic otoscopy or tympanography can be used to measure changes in middle ear compliance.

In a perforated tympanic membrane, the manometer of the impedance bridge can be used to measure middle ear pressure changes. Previous Next: Other Tests of Eustachian Tube Function Other tests have been developed for assessment of eustachian tube function. A 9-step inflation-deflation tympanometric test is used to assess changes in resting middle ear pressure after applying positive and negative ear canal pressures while the patient is swallowing. Other methods include microflow technique, impedance method, sonometry, forced response test, and videoendoscopy of the nasopharyngeal end of the eustachian tube. A self-described method by patients with perforated tympanic membranes is the bitter taste of ear drops in the mouth when used topically. This indicates a patent eustachian tube. A final testing mechanism is sonotubometery. The advantage of this diagnostic test is the ability to evaluate the eustachian tube function with or without an intact tympanic membrane under physiologic conditions.

Previous Contributor Information and Disclosures Author Ted L Tewfik, MD Professor of Otolaryngology-Head and Neck Surgery, Professor of Pediatric Surgery, McGill University Faculty of Medicine; Senior Staff, Montreal Children's Hospital, Montreal General Hospital, and Royal Victoria Hospital Ted L Tewfik, MD is a member of the following medical societies: American Society of Pediatric Otolaryngology , Canadian Society of Otolaryngology-Head & Neck Surgery Disclosure: Nothing to disclose. Harpreet Singh, MBBS, MS FRACGP, General Physician (ENT), Head and Neck Surgeon, Australia Disclosure: Nothing to disclose. Specialty Editor Board Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Received salary from Medscape for employment. for: Medscape. Gerard J Gianoli, MD Clinical Associate Professor, Departments of Otolaryngology-Head and Neck Surgery and Pediatrics, Tulane University School of Medicine; President, The Ear and Balance Institute; Board of Directors, Ponchartrain Surgery Center Disclosure: Nothing to disclose.

Chief Editor Arlen D Meyers, MD, MBA Professor of Otolaryngology, Dentistry, and Engineering, University of Colorado School of Medicine Arlen D Meyers, MD, MBA is a member of the following medical societies: American Academy of Facial Plastic and Reconstructive Surgery , American Academy of Otolaryngology-Head and Neck Surgery , American Head and Neck Society Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Cerescan;RxRevu;SymbiaAllergySolutions<br/>Received income in an amount equal to or greater than $250 from: Symbia<br/>Received from Allergy Solutions, Inc for board membership; Received honoraria from RxRevu for chief medical editor; Received salary from Medvoy for founder and president; Received consulting fee from Corvectra for senior medical advisor; Received ownership interest from Cerescan for consulting; Received consulting fee from Essiahealth for advisor; Received consulting fee from Carespan for advisor; Received consulting fee from Covidien for consulting.

Additional Contributors B Viswanatha, DO, MBBS, PhD, MS, FACS Professor of Otolaryngology (ENT), Sri Venkateshwara ENT Institute, Victoria Hospital, Bangalore Medical College and Research Institute, India B Viswanatha, DO, MBBS, PhD, MS, FACS is a member of the following medical societies: Indian Medical Association , Indian Society of Otology , Association of Otolaryngologists of India Disclosure: Nothing to disclose. Acknowledgements Emad Massoud, MB, BCh, MSc, FRCS(C) Associate Professor, Program Director, Department of Surgery, Division of Otolaryngology-Head & Neck Surgery, Dalhousie University, Canada What is the function of the Eustachian tube? | Reference.com What is the function of the Eustachian tube? A: Quick Answer The Eustachian tube is used to equalize air pressure between the middle ear and the surrounding area, but it is also used to drain mucus from the middle ear. Keeping the pressure in a person's head equalized helps with balance and preventing dizziness. The removal of mucus keeps infection from spreading to the middle ear.

Full Answer The Eustachian tube connects the middle ear cavity with the part of the body called the nasopharynx. The opening and closing function of the middle ear not only regulates the pressure in the ear, but it helps protect the eardrum from loud noises. When the Eustachian tube is not working properly, there are numerous symptoms that can appear. There can be pain in the area due to the unequal pressure between the middle ear and the rest of the area. Dizziness can occur from the incorrect pressure in the head. The tube not working properly can be one of the main causes of ringing in the ears. Sometimes the issues with the Eustachian tube can be alleviated or corrected by swallowing, yawning or chewing. These motions cause the pressure to fluctuate in the tube and can sometimes even the pressure back out. Issues with the Eustachian tube not functioning properly can be caused by sinus infections, colds or other upper respiratory infections. Fun Ear Facts for Kids - Interesting Information about Human Ears & Hearing Fun Ear Facts for Kids Check out our fun ear facts for kids and enjoy a wide range of interesting information about human ears.

Learn about the different parts that make up your ears, how they communicate with your brain, what Eustachian tubes are, how hearing works, why we produce ear wax and much more. Read on and have fun learning about ears! Our ears help us detect sound. Ears convert sound waves into nerve impulses that are sent to the brain. While your ears pick up the sound, it is your brain that does the hard work of making sense of it all. There is much more to the ear than the part you can see on the outside of your head. The middle part of the ear (behind the ear drum) amplifies sound pressure. The middle ear also contains the Eustachian tube which helps equalize pressure and drain mucus. Ear infections are more common in children because of their developing immune systems and differences between their Eustachian tubes and those of adults. The inner ear is found inside the temporal bone, the hardest bone in the human body. The inner ear contains the spiral shaped hearing organ called the cochlea as well as the vestibule and semicircular canals which help with balance. Sounds waves are passed from air to liquid in the inner air.

The inner air also contains tiny hair cells which react to sound waves, triggering chemicals that are sent to the brain as nerve impulses. Abnormalities in the inner ear of humans can cause deafness. Skin glands in the ear canal produce ear wax which helps protect the ear by lubricating it and cleaning it of dirt and dust. Excessive ear wax can impair hearing, especially if it is pressed hard against the eardrum. Ear wax normally comes out of your ear naturally so it’s not a good idea to try and remove it yourself unless it is causing health problems (best to see your doctor first). Piercing earlobes and ornamenting them with jewellery has been common practice around the world for thousands of years for both for cultural and cosmetic reasons. eustachian tube | anatomy | Britannica.com Eustachian tube tympanic membrane Eustachian tube, also called Auditory Tube, tube that extends from the middle ear to the pharynx (throat).

About 3 to 4 centimetres (1.2–1.6 inches) long in humans and lined with mucous membrane , it is directed downward and inward from the tympanic cavity, or middle ear, to that portion of the pharynx called the nasopharynx, the space above the soft palate and behind and continuous with the nasal passages. The upper end of the eustachian tube is narrow and surrounded by bone . As it nears the pharynx, the tube becomes wider and cartilaginous. The mucous lining is continuous with that of the middle ear. Small cilia (hairlike projections) cover it to aid the drainage of mucous secretions from the middle ear to the pharynx. The main function of the auditory tube is ventilation of the middle ear and maintenance of equalized pressure on both sides of the tympanic (drum) membrane. Closed at most times, the tube opens during swallowing. This permits equalization of the pressure without conscious effort. During an underwater dive or rapid descent in a plane the eustachian tube may remain closed in the face of rapidly increasing surrounding pressure.

The pressure on both sides of the eardrum membrane can usually be equalized by holding the nose and blowing, by swallowing, or by wiggling the jaws. Learn More in these related articles: e-Tutor - Anatomy Of A Frog Anatomy Of A Frog by e-Tutor Staff In this lesson module you will learn about the different parts of a frog. You will also virtually dissect a frog. Lesson Problem What is the anatomy of a frog? Vocabulary ventricle Study Guide Frogs are amphibians, living both on land and in water. Their anatomy is very unique. Their bodies are similar to humans in that they have skin, bones, muscles, and organs. The body of a frog can be divided into a head, a short neck, and a trunk. The head contains the brain, mouth, eyes, ears and nose. The frog's head movement is limited due to the short, almost rigid neck. The trunk of a frog forms walls for a single body cavity known as the coelom. The coelom holds all of the frog's internal organs. Frogs have the same kinds of organs as humans and the same organ systems. For example, frogs have a long, sticky tongue which they use to capture food.

They also have teeth, which unfortunately are very weak and rather useless. Humans have tongues and teeth as well (and a mouth of course). If you closely examine the head of a frog, you will find the following: eye sockets, eyes, mouth, tongue, vomerine teeth, maxillary teeth, gullet teeth, external nostrils, internal nostrils, the glottis opening, eustachian tube openings, the tympanic membranes and the esophagus. The eyes, the mouth and the nostrils are all examples of a frog's external structures. In addition, a frog's external structures also include the webbed feet and the cloaca opening. The tympanic membranes or eardrums are exposed, but a frog does not have external ears. The internal structures of a frog include: the heart, the lungs, the kidneys, the stomach, the liver, the small intestine, the large intestine, the spleen, the pancreas, the gall bladder, the urinary bladder, the cloaca, the ureter, the oviducts, the testes, the ovaries and fat bodies. Again, the frog has organs that are similar to those of humans.

For example, a frog has a brain, kidneys, lungs, eyes, a stomach, intestines and a heart. The one major difference between the anatomy of a frog and that of humans is that the is simpler than the anatomy of a man. Frogs don't have ribs or a diaphragm. Humans have both and a diaphragm (thoracic diaphragm) plays an important function in breathing and respiration. Breathing takes oxygen in and carbon dioxide out of the body. Respiration is the process by which our cells are provided with oxygen for metabolism and carbon dioxide, which is produced as a waste gas, is removed. A frog uses its tongue for grabbing prey. The vomarine and maxillary teeth are used for holding the prey. The internal nostrils are used by the frog for breathing. The tympanic membrane is the eardrum. It is located behind the frog's eyes. The eustachian tubes equalize the pressure in the frog's inner ear. The glottis is a tube, which leads to the lungs, while the esophagus is a tube which leads to the frog's stomach. The stomach helps the frog break down food and the liver also helps with digestion (it makes bile).

Bile (also known as gall) is a fluid secreted by hepatocytes from the liver of most vertebrates (humans and frogs are vertebrates). Hepatocytes are cells present in the liver, and they initiate the formation and secretion of bile. In many species, bile is stored in the gall bladder between meals. When eating, the bile is discharged into the duodenum. Bile, therefore helps with digestion. The duodenum, which is the first and shortest part of the small intestine, is responsible for the breakdown of food in the small intestine. Most chemical digestion takes place in the duodenum. The small intestine absorbs nutrients from food. The large intestine absorbs water. It also collects waste. You can also think of the cloaca as storing waste, as this part of the frog collects eggs, sperm, urine and feces. The cloaca (opening) is also where sperm, eggs, urine, and feces exit the frog's body. The spleen stores blood, while the kidneys filter the blood. The ureters carry urine from the kidneys to the bladder. The (urinary) bladder stores urine. The testes make sperm, while the ovaries makes eggs and the eggs travel through the oviducts.

A frog's skin is always moist. It is made up of two layers, an outer epidermis and an inner dermis. In addition to protecting the frog, the skin also helps the frog breathe. A frog will take in oxygen from the water through their skin. The oxygen in the water passes through their skin and goes directly to their blood. Frogs also have a pair of lungs which allows them to breathe when on land. A frog has very few bones. They make up the skeleton of the frog. The skull (head bone) is large and flat. The legs are long for jumping. In addition to being specialized for jumping, the bones in their upper and hind legs are also specialized for leaping. The muscles move the skeleton of the frog. The muscles help the frog jump and swim. Frogs have other systems similar to humans that are a part of their bodies. For example, a frog has a nervous system (all of the nerves and the spine), a circulatory system (the heart and blood going through the body) and a digestive system (the food going through the mouth to the intestines). The heart (which is part of the circulatory system) is three-chambered.

There are two atria and one ventricle. There is a valve within the frog's heart known as the spiral valve. It directs the flow of blood to prevent oxygenated and de-oxygenated blood from mixing. A frog's sense of hearing (which is part of the nervous system) is highly developed. Frogs can detect high-pitched sounds with their ears. In addition to breathing oxygen through their skin when in water, frogs can also detect low-pitched sounds through their skin. Another highly developed system is a frog's sense of sight and smell (which again are both part of the nervous system). Frogs detect predators and prey using their large eyes. Their eyes however have poorly developed eyelids, which do not close. In order to close its eye, a frog has to draw the eye into its socket. There is a third eyelid, known as the nictitating membrane. It can be drawn over the pulled in eye (eyeball). Frogs also use their sense of smell to detect chemical signals. These signals help them to identify potential food. Now that we know the basics of frog anatomy , let's move onto the Activities and Extended Learning.

Activities Print Extended Learning Write some of the things you have learned about frogs from the Study Guide. Answer the following questions in complete sentences, using your own words: 1. How are frogs adapted for aquatic life? ____________________________________________________________________________________________ Middle Ear, Eustachian Tube, Inflammation/Infection: Background, Pathophysiology, Epidemiology Middle Ear, Eustachian Tube, Inflammation/Infection Updated: Apr 20, 2015 Author: Robert B Meek, MD; Chief Editor: Arlen D Meyers, MD, MBA more... Share Overview Background Middle ear and eustachian tube inflammation are common denominators in various clinical conditions, namely, acute otitis media (AOM), chronic otitis media with effusion (COME), and eustachian tube dysfunction (ETD). [ 1 ] Next: Pathophysiology Acute otitis media (AOM) can be described on the cellular and molecular level as a transudation of neutrophils, serum, and inflammatory mediators into the middle ear space. This transudation is associated with mucosal edema of the middle ear and bacterial or viral infection of the eustachian tube and middle ear space.

Chronic otitis media (COM) involves a transudation of serum with less cellularity of the effusion material. The inflammatory mediators are less destructive, and bacteria and viral antigens may be less prevalent. See the image below. Anatomy of the external and middle ear. Previous Frequency United States Otitis media (OM) is the most common diagnosis made by office-based physicians of children younger than 15 years. Otitis media (OM) is the most common reason children are prescribed antibiotics and the most common indication for surgery in children. A study by Hasegawa et al, using a cross-sectional analysis of the Nationwide Emergency Department Sample, found that otitis media was the second most common cause of infectious disease – related emergency department visits in the United States in 2011. The study found that otitis media was diagnosed in 18% of such cases, compared with upper respiratory infection in 41% of cases. [ 2 ] International Rates of otitis media (OM) equal to or higher than rates in the United States are noted internationally, especially in less developed countries.

A delay is evident in the peak incidence of otitis media (OM) in European children, which may be attributable to the fact that European children enter childcare at a later age. Mortality/Morbidity In the era of modern medicine, middle ear infection rarely leads to mortality, except in rare cases of intracranial spread of infection. Eustachian tube dysfunction (ETD) and chronic otitis media with effusion (COME) affect 70% of children by age 7 years and are common causes of childhood hearing loss. Morbidity from otitis media (OM) primarily stems from the effect on hearing. In most cases the conductive hearing loss is entirely reversible with medical or surgical treatment. Children may have a speech/language acquisition delay from recurrent acute otitis media (AOM) or chronic otitis media with effusion (COME). Otitis media (OM) has not clearly been shown to affect the long-term acquisition of language skills in children; however, studies have predicted that early recurrent otitis media (OM) and chronic otitis media with effusion (COME) may be predictive of future decreases in hearing as measured by school screening tests and a decrease in overall school achievement.

These findings suggest a possible long-term effect on the central auditory pathway. Race American Indian and Native Alaskan children, including the Inuit, have higher rates of chronic otitis media (COM) than whites. Hispanic children have higher rates of otitis media (OM) than either whites or African American children. The prevalence of chronic suppurative otitis media (OM) is highest in Inuits of Alaska, Canada, and Greenland; Australian Aborigines; and in American Indians. High prevalence is also found in Pacific Islanders and Africans. Low prevalence is found in residents of Korea, India, and Saudi Arabia. The lowest prevalence is found in residents of the United States, United Kingdom, Denmark, and Finland. Sex Males have a higher prevalence of acute otitis media (AOM) and undergo myringotomies and tympanoplasties more frequently than females do. Age Middle ear dysfunction and eustachian tube dysfunction (ETD) are more common in the pediatric age group. Peak incidence of otitis media (OM) is in the first 2 years of life.

[ 3 ] Previous References Swarts JD, Alper CM, Luntz M, Bluestone CD, Doyle WJ, Ghadiali SN, et al. Panel 2: Eustachian tube, middle ear, and mastoid--anatomy, physiology, pathophysiology, and pathogenesis. Otolaryngol Head Neck Surg. 2013 Apr. 148(4 Suppl):E26-36. [Medline] . Hasegawa K, Tsugawa Y, Cohen A, et al. Infectious Disease-related Emergency Department Visits Among Children in the United States. Pediatr Infect Dis J. 2015 Apr 8. [Medline] . Handzic J, Radic B, Bagatin T, Savic A, Stambolija V, Nevajda B. Hearing in children with otitis media with effusion--clinical retrospective study. Coll Antropol. 2012 Dec. 36(4):1273-7. [Medline] . Doyle WJ, Alper CM, Buchman CA, Moody SA, Skoner DP, Cohen S.

Illness and otological changes during upper respiratory virus infection. Laryngoscope. 1999 Feb. 109(2 Pt 1):324-8. [Medline] . Niemelä M, Pihakari O, Pokka T, Uhari M. Pacifier as a risk factor for acute otitis media: A randomized, controlled trial of parental counseling. Pediatrics. 2000 Sep. 106(3):483-8. [Medline] . Contencin P, Maurage C, Ployet MJ, Seid AB, Sinaasappel M. Gastroesophageal reflux and ENT disorders in childhood. Int J Pediatr Otorhinolaryngol. 1995 Jun. 32 Suppl:S135-44. [Medline] . Tarabichi M, Najmi M. Visualization of the eustachian tube lumen with Valsalva computed tomography. Laryngoscope. 2015 Mar. 125(3):724-9. [Medline] .

Sudhoff H, Schröder S, Reineke U, Lehmann M, Korbmacher D, Ebmeyer J. [Therapy of chronic obstructive eustachian tube dysfunction : Evolution of applied therapies]. HNO. 2013 Jun. 61(6):477-82. [Medline] . Gluth MB, McDonald DR, Weaver AL, Bauch CD, Beatty CW, Orvidas LJ. Management of eustachian tube dysfunction with nasal steroid spray: a prospective, randomized, placebo-controlled trial. Arch Otolaryngol Head Neck Surg. 2011 May. 137(5):449-55. [Medline] . Haddad J Jr, Saiman L, San Gabriel P, et al. Nonsusceptible Streptococcus pneumoniae in children with chronic otitis media with effusion and recurrent otitis media undergoing ventilating tube placement. Pediatr Infect Dis J. 2000 May. 19(5):432-7. [Medline] . Black S, Shinefield H, Fireman B, et al.

Efficacy, safety and immunogenicity of heptavalent pneumococcal conjugate vaccine in children. Northern California Kaiser Permanente Vaccine Study Center Group. Pediatr Infect Dis J. 2000 Mar. 19(3):187-95. [Medline] . Asbjornsen A, Holmefjord A, Reisaeter S, et al. Lasting auditory attention impairment after persistent middle ear infections: a dichotic listening study. Dev Med Child Neurol. 2000 Jul. 42(7):481-6. [Medline] . Bernstein JM. Immunologic reactivity in the middle ear in otitis media with effusion. Otolaryngol Clin North Am. 1991 Aug. 24(4):845-58. [Medline] . Block SL, Hedrick J, Harrison CJ, et al. Community-wide vaccination with the heptavalent pneumococcal conjugate significantly alters the microbiology of acute otitis media. Pediatr Infect Dis J. 2004 Sep. 23(9):829-33. [Medline] .

Bluestone CD. Epidemiology and pathogenesis of chronic suppurative otitis media: implications for prevention and treatment. Int J Pediatr Otorhinolaryngol. 1998 Jan. 42(3):207-23. [Medline] . Casey JR, Pichichero ME. Changes in frequency and pathogens causing acute otitis media in 1995-2003. Pediatr Infect Dis J. 2004 Sep. 23(9):824-8. [Medline] . Conrad DA. Should acute otitis media ever be treated with antibiotics?. Pediatr Ann. 1998 Feb. 27(2):66-7, 70-4. [Medline] . Contencin P, Narcy P. Nasopharyngeal pH monitoring in infants and children with chronic rhinopharyngitis. Int J Pediatr Otorhinolaryngol. 1991 Oct. 22(3):249-56. [Medline] . Daly KA, Giebink GS. Clinical epidemiology of otitis media.

Pediatr Infect Dis J. 2000 May. 19(5 Suppl):S31-6. [Medline] . Ghaffar F, Barton T, Lozano J, et al. Effect of the 7-valent pneumococcal conjugate vaccine on nasopharyngeal colonization by Streptococcus pneumoniae in the first 2 years of life. Clin Infect Dis. 2004 Oct 1. 39(7):930-8. [Medline] . Heikkinen T. Role of viruses in the pathogenesis of acute otitis media. Pediatr Infect Dis J. 2000 May. 19(5 Suppl):S17-22; discussion S22-3. [Medline] . Ilicali OC, Keles N, Deger K, Savas I. Relationship of passive cigarette smoking to otitis media. Arch Otolaryngol Head Neck Surg. 1999 Jul. 125(7):758-62. [Medline] .

Meek RB 3rd, McGrew BM, Cuff CF, Berrebi AS, Spirou GA, Wetmore SJ. Immunologic and histologic observations in reovirus-induced otitis media in the mouse. Ann Otol Rhinol Laryngol. 1999 Jan. 108(1):31-8. [Medline] . Niemelä M, Uhari M, Möttönen M, Pokka T. Costs arising from otitis media. Acta Paediatr. 1999 May. 88(5):553-6. [Medline] . Pelton SI. Otitis media: re-evaluation of diagnosis and treatment in the era of antimicrobial resistance, pneumococcal conjugate vaccine, and evolving morbidity. Pediatr Clin North Am. 2005 Jun. 52(3):711-28, v-vi. [Medline] . Pelton SI, Loughlin AM, Marchant CD. Seven valent pneumococcal conjugate vaccine immunization in two Boston communities: changes in serotypes and antimicrobial susceptibility among Streptococcus pneumoniae isolates.

Pediatr Infect Dis J. 2004 Nov. 23(11):1015-22. [Medline] . Pichichero ME. A review of evidence supporting the American Academy of Pediatrics recommendation for prescribing cephalosporin antibiotics for penicillin-allergic patients. Pediatrics. 2005 Apr. 115(4):1048-57. [Medline] . Pichichero ME, Reiner SA, Brook I, et al. Controversies in the medical management of persistent and recurrent acute otitis media. Recommendations of a clinical advisory committee. Ann Otol Rhinol Laryngol Suppl. 2000 Aug. 183:1-12. [Medline] . Rinaldo A, Ferlito A. The pathology and clinical features of "glue ear": a review. Eur Arch Otorhinolaryngol. 2000. 257(6):300-3. [Medline] . Rovers MM, Straatman H, Ingels K, van der Wilt GJ, van den Broek P, Zielhuis GA.

The effect of ventilation tubes on language development in infants with otitis media with effusion: A randomized trial. Pediatrics. 2000 Sep. 106(3):E42. [Medline] . Rovers MM, Zielhuis GA, Straatman H, Ingels K, van der Wilt GJ, van den Broek P. Prognostic factors for persistent otitis media with effusion in infants. Arch Otolaryngol Head Neck Surg. 1999 Nov. 125(11):1203-7. [Medline] . Ruuskanen O, Arola M, Putto-Laurila A, et al. Acute otitis media and respiratory virus infections. Pediatr Infect Dis J. 1989 Feb. 8(2):94-9. [Medline] . Shaw CB, Obermyer N, Wetmore SJ, Spirou GA, Farr RW. Incidence of adenovirus and respiratory syncytial virus in chronic otitis media with effusion using the polymerase chain reaction. Otolaryngol Head Neck Surg. 1995 Sep.

113(3):234-41. [Medline] . Skull SA, Morris PS, Yonovitz A, et al. Middle ear effusion: rate and risk factors in Australian children attending day care. Epidemiol Infect. 1999 Aug. 123(1):57-64. [Medline] . Takahashi M, Peppard J, Harris JP. Immunohistochemical study of murine middle ear and Eustachian tube. Acta Otolaryngol. 1989 Jan-Feb. 107(1-2):97-103. [Medline] . Uhari M, Hietala J, Tuokko H. Risk of acute otitis media in relation to the viral etiology of infections in children. Clin Infect Dis. 1995 Mar. 20(3):521-4. [Medline] . US Otitis Media Guideline Panel, Stool SE, US Agency for Health Care Policy and Research. Otitis media with effusion in young children/Otitis Media Guideline Panel. Rockville, Md: US Dept.

of Health and Human Services, Public Health Service; 1994. Clinic practice gudeline, No. 12. Wright CG, Meyerhoff WL. Pathology of otitis media. Ann Otol Rhinol Laryngol Suppl. 1994 May. 163:24-6. [Medline] . Zhou F, Shefer A, Kong Y, Nuorti JP. Trends in acute otitis media-related health care utilization by privately insured young children in the United States, 1997-2004. Pediatrics. 2008 Feb. 121(2):253-60. [Medline] . Zielhuis GA, Gerritsen AA, Gorissen WH, et al. Hearing deficits at school age; the predictive value of otitis media in infants. Int J Pediatr Otorhinolaryngol. 1998 Aug 1. 44(3):227-34. [Medline] . Media Gallery Anatomy of the external and middle ear.

of 1 Eustachian Tube Institute | Dr Oskar Kujawski | ENT Surgery | Geneva, Switzerland Eustachian Tube Institute Welcome to the Eustachian Tube Institute web site which I hope you will find of interest. Eustachian Tube Surgery and general ENT information is presented here in several languages home page > Eustachian Tube Surgery / ENT Surgery Home Eustachian Tube ENT Dysfunction Solutions Diving Parents Kids ENT basics Aviation Physicians Disclaimer Reference EUSTACHIAN TUBE PROLOGUE Dr. Oskar Kujawski is in charge of the Geneva based Eustachian Tube Institute. His international expertise in ENT and Head and Neck Surgery is world known. He focuses his efforts on Eustachian tube management ( ENT Surgery ). Today, many illnesses (such as Otitis Media in children and in adults, some deafness’s and tinnitus, Patulous Eustachian tube with autophonia, dizziness and hyperacousia, air traveling and diving ears problems) may now be resolved. Being the first world specialist to develop Eustachian tube surgery, he is inventor of specific surgical instruments to this field.

This leader position pushes him to publish in international journals and book, and to teach this revolutionary surgery around the world, through international courses organized in Geneva as abroad. He is official instructor in the American Academy of ENT and Head and Neck Surgery, and President elected of the international Eustachian tube standing committee in European Academy of Otology and Neuro Otology. In order to aware people to these new approaches for so many illness till today not resolved, he put the first interactive web site on this topic on Internet ; designated for physicians, parents, children's, divers and air travelers who regularly suffer. Anatomy and physiology are a part of the oldest branches of medicine. The Eustachian tube is one of the most complicated structures in the human body. The first reports date back to ancient Egyptian times (Ebers, Papyrus 1600 BC). The conviction that Eustachian tube is a link / bridge between nose and ears and play a fundamental role for the good functioning of the ear led Otologists, consulted by the patients, to describe and to propose premises of therapeutic and diagnostic management.

Eustachius Bartolommeo (1510-1574) made the first description of this auditory canal that bears his name (original anatomical drafts of Eustachius). However, many other pioneers brought there knowledge and discoveries as Alcmaeon, Duverney, Valsalva, Von Tröltsch, Rich, Politzer, Toynbee, Bonnafont, Roure, etc... They were all otologist, oriented to the ear. But the fundamental physiological key of Eustachian tube is “Dynamic”. It was discovered and proved only few years ago (Kujawski, Poe). The heart of this real dynamic system seems to be situated in the median third of the cartilaginous portion, named the tubal valve. Your plane is going to land in Geneva and your seat belt is well fasted? Do you become deaf? Do you start ears pain? Swallow, yawning or sucking a candy is not sufficient to clear them? Your children has its third otitis this winter, or his teacher pretends that he is deaf? A common guilty : the Eustachian tubes.

The audition of a noise comparable to the bruising of a tissue paper while, swallowing or yawning indicates their opening. Much more than a duct joining ear to nose, this complex organ ensures pressures balance in your ears in order to guarantee an optimal hearing during day and night, by plane or during a commonplace cold. This dysfunction generates ear infections (otitis), deafness, tinnitus and even dizziness. To break the antibiotics vicious circle to ensure yours or your child’s hearing we can now approach a new preventive and curative solution of all tubal dysfunctions, common and complex, at the origin to these middle ear disease. In cases of acute otitis, recurrent otitis media with or without effusion and some dizziness in the Ménières syndrome surgical puncture of the eardrum, with or without setting up of a ventilation tube or grommet can be now avoided. Several tinnitus may be secondary to a tubal dysfunction as well as some acute or sudden deafness.

A Brief History of the Eustachian Tube | Jaipreet Virdi A Brief History of the Eustachian Tube Posted on by Jai Virdi The Eustachian tube is a passageway that lies between the middle ear and the pharynx, the upper part of the mouth located just below the top of the nose. One of the primary functions of the tube is to equalize ear pressure between the middle ear and the atmosphere; most of the time the tube is closed, but it can open to let in a small amount of air to prevent damage to the ear. Early mentions of the tube dates back to Alcmaeon of Sparta around 500B.C., who constructed a basis for understanding medicine via dissection, and thought the tube enabled goats to breathe through their ears as well as noses. [1] Other Greek philosophers, including Aristotle and Celsus, also vaguely referred to the tube’s existence, but did not elaborate on its function or purpose. The Eustachian Tube (from University of Maryland Medical Center) The surge of Italian anatomists during the Renaissance period and their emphasis on dissection brought forth new understandings of the body and its parts.

Andreas Vesalius (1514-1564), Professor of Anatomy of Padua, provided detailed descriptions of two of the tiny bones in the middle ear (the malleus and incus), but although he was aware of the existence of the Eustachian tube, he does not comment on its role in hearing. His contemporary, Bartholomeus Eustachius (1510-1574) who held the Chair of Anatomy at Rome, published the first detailed anatomical description of the tube in his 1562 Epistola de auditus organis (Examination of the Organ of Hearing), possibly the first treatise on the ear: It originates at the anterior course of the base of the skull, and takes an anterior course toward the pterygoid process of the sphenoid bone. It consists of two parts: the first solidly connected with the temporal bone, close to the tympanic cavity; the second soft, partly ligamentous, partly cartilaginous, directed towards the nasopharyx. Cross sections of the tube are not perfectly round and the inner part is twice as wide as the outer.

[2] Bartholomeus Eustachius Comparing the tube to a quill pen, Eustachius provided precise descriptions of its structure and position in the face, but he made no mention of its function: Comparing to a Quill pen (Wellcome Library Images) Nor did he publish an engraving of the tube as part of the external auditory system in his 1651 Tabuli Anatomiceu, which also contained detailed figures of the ear ossicles and the tympanum membrane in man and dog. [3] It is likely that Eustachius held the long-standing belief that the Eustachian tube functioned as (another) avenue for breathing, since he postulated that other parts of the ear, especially the ossicles and tympanum, were involved in the mechanism of sound transduction. Not until 1683, with the work of French anatomist Guichard Joseph DuVerney (1648-1730) was this belief corrected.

In Traité de l’organe de l’ouie, DuVerney described the Eustachian tube as a means for renewing air within the tympanum and for equalizing air pressure, believing that the tube was always open and it was the eardrum that maintained the flow of air. Anatomy of the Human ear (1686); Steven Blankaart & Guichard Joseph Duverney (Wellcome Library Images) Descriptions of the Eustachian tube contained more than just anatomy: they highlighted the physiological and therapeutic importance of diagnosing and treating ear diseases confined to the Eustachian tube or tympanum. Antoine Maria Valsalva (1666-1732) is historically credited for giving the tube its eponymous name in honor of Eustachius, whose work set the foundation for understanding the anatomy and physiology of the ear. Valsalva, a pupil of the famed physician Marcello Malpighi (1628-1694), was appointed Professor of Anatomy at the University of Bologna in 1705, where his main interests were on anatomy and the function of the middle and internal ear.

Antonio Maria Valsalva. Line engraving by R. Ceracchi. (Wellcome Library Images) In 1705, Valsalva published De aure humana tractatus, which followed years of intense observations, animal experiments, and numerous dissections; the treatise included enhanced descriptions of the physiology and pathology of the ear, even demonstrating communication between the mastoid cells and the tympanic cavity. Valsalva also outlined the function of the Eustachian tube and its diagnostic use; the tube, he claimed, worked alongside the pharyngeal muscles of the ear. Believing that Eustachian tube blockages were among the main causes of deafness, in De aure, Valsalva also outlined his “Valsalvian maneuver,” a method consisting of the forced expiration of air through the Eustachian tube with the mouth and nostrils closed, thus resulting in increased pressure to the tympanic membrane. The procedure dates back to Arab physicians in the 11th century and was used as a remedy for cleansing the middle ear from pus, and hence, unblocking the ear and restoring hearing. [4] NOTES [1] Charles D.

Bluestone, Eustachian Tube: Structure, Function, and Role in Otitis Media, Vol.2 (PMPH-USA, 2005), 4. [2] Translated & quoted in Bluestone, Eustachian Tube, 5. [3] Most of Eustachius’ works were not published during his lifetime or simply lost. His copper plates of anatomical engravings were discovered early in the eighteenth century and presented by Pope Clement XI to his physician Lanncisi (1655-1720), who then published the plates in 1712. Unlike Vesalius, Eustachius’ plates represented dead, not living anatomy. [4] Steven H. Yale, “Antonio Maria Valsalva (1666-1723), Clinical Medical & Research 3: 35-38. The Valsalva maneuver remains a staple in modern medicine, having been adapted as a diagnostic procedure in modern cardiology for assessing heart murmurs and heart failure. Share this:

Question: In which part of the human body is the Eustachian Tube?
Answer: Ear