Otoscopes and otoscopy
Position of otoscope for ear exam
An ear exam can find problems in the ear canal, eardrum, and the middle ear. During an ear exam, a tool called an otoscope is used to look at the outer ear canal and eardrum. The otoscope has a light, a magnifying lens, and a funnel-shaped viewing piece with a narrow, pointed end called a speculum.
The doctor holds the otoscope in one hand and uses his or her free hand to pull the outer ear gently up and back. This straightens the ear canal and helps the doctor see inside the ear. In babies younger than 12 months, the doctor will gently pull the outer ear down and back.
If you are doing a home ear exam with an otoscope, be sure to look into the otoscope before you move it forward. Make sure you can see the path of the ear canal. You do not need to insert the viewing piece very far into the ear. Angle the tip of the viewing piece slightly toward the person's nose to follow the normal path of the canal. While you look through the otoscope, move it gently at different angles so that you can see the ear canal walls and the eardrum. Stop at any sign of increased pain.
Examine the good ear first
Examine the good ear first. This has several advantages: it prevents the spread of infection into an unaffected ear, it usually allows you to see some normal anatomy with which to compare the other side, and also helps stop you relaxing once you have identified one abnormality, failing to see less obvious but often more important findings - a common problem of students. With the light source turned up full, use the otoscope as a torch to examine the pinna briefly for meatal abnormalities and previous surgical wounds.
The commonest scars around the ear are those from postaural and endaural incisions. Eczema around the meatus usually indicates the presence of otitis externa. With your free hand, gently pull the pinna upwards and backwards to straighten the external ear canal. This is not usually necessary in young children as the canal is straighter. While resting the side of your hand against the patient's temple introduce the speculum gently into the canal. The patient may cough as the cutaneous branch of the vagus is stimulated.
What to look for
Examine the external canal and the tympanic membrane systematically. You should learn figure 3 thoroughly because if you are not sure what you should be looking for you will undoubtedly miss things.
Firstly, look at the external canal wall. Does the skin look normal or is it inflamed with debris in the canal (otitis externa)? Next identify the handle of the malleus. If it is not immediately obvious then look for its lateral process, which is rarely absent.
You should then inspect the pars tensa systematically, starting in the posterosuperior quadrant and then moving forwards, downwards, and backwards until all 360?has been covered. Try to identify as many structures as you can. Finally, carefully inspect the pars flaccida - this is where abnormalities are often missed.
To make sure you do not miss anything ask yourself the following questions.
Can I clearly see all the external auditory canal? - The canal may be absent, stenotic, oedematous, or filled with wax, debris, blood, or a foreign body. You may be able to remove material to obtain a better view, but if there is a strong possibility of a perforation in the tympanic membrane, the patient should be referred to an ear, nose, and throat surgeon as syringing can damage the middle ear structures in such patients.
Can I see the tympanic membrane or the handle of the malleus, or both? - The deeper part of the canal can again be obscured by wax or other material. Rarely the membrane and malleus may be completely absent - for example, after certain ear operations. The handle may be visible even if most of the pars tensa is absent; the handle gives you an indication of where the membrane should have been.
Is the tympanic membrane intact? - Be careful to note the difference between a retracted drum and a perforation. Usually the small blood vessels in the middle ear mucosa give you a clue. If there is any debris or white keratin around the edge of the pars tensa or, more commonly, over the pars flaccida the patient may have an occult cholesteatoma (skin debris within the middle ear cavity) and should be referred for a specialist opinion.
Is the tympanic membrane the right colour and transparency? - Although the normal appearance of the membrane varies greatly, a gold or blue colouration or a dull membrane usually indicates fluid in the middle ear. White patches in the membrane are called tympanosclerosis. Small chalk patches are extremely common. Thicker tympanosclerotic plaques are usually due to previous surgery. Both types usually have no clinical importance unless the results of tuning fork tests are abnormal.
Common problems
I can't see properly - It is important to check the light is adequate and the battery is fully recharged. An undercharged unit will produce a poor light and subtle changes in the colour of the tympanic membrane may not be accurately detected.
All I can see is a red drum - What you are most likely to be looking at is the posterior canal wall. Try tilting the otoscope anteriorly and superiorly or pulling the pinna slightly further to straighten out the canal and assist your view.
The anatomy is so abnormal I can't work out what is what - Try looking for the lateral process of the malleus. Even if most other structures have been destroyed this is often visible. Once you can identify the lateral process, orientation will be much easier.
I'm not sure if there is a perforation or not - In most cases a perforation is obvious, but the sharp mouth of a deep retraction pocket can look remarkably similar. If you can see blood vessels in the middle ear mucosa these confirm the presence of a perforation. If it is difficult to tell, an ear, nose, and throat surgeon may use a pneumato-otoscope attachment, which fits into a socket in the head of more expensive otoscopes. This attachment can produce negative or positive pressure in the ear canal, producing visible movement in an intact drum.
Although this is not a comprehensive system, it should give you some idea of the likely abnormality. If you are in any doubt refer the patient to an ear, nose, and throat specialist.
The following taken from the University of Bristol’s wonderful web site: http://www.bris.ac.uk/Depts/ENT/otoscopy_tutorial.htm
Otoscopes and otoscopy
/ Illumination is paramount. Run down batteries and dim lights will make you job even more difficult and will sometimes alter your perception of the image you see.If you are handed an otoscope with worn out batteries, insist that they are replaced. Most modern hand held otoscope have a very bright bulb that is more than adequate for the job.
Use the biggest earpiece that you can fit in to the ear canal. Small earpieces may be easy to use but the amount of visual information you get is very limited.
/ Hold the otoscope at the end nearer the eyepiece, this way movement of your hand and arm is not translated into as much movement of the tip of the otoscope in the ear canal which may cause discomfort.
/ Holding the otoscope at the end like this can lead to increased discomfort if you move your hand suddenly
The ear canal
/ The ear canal tends to have a slight anterior bulge and it is usually easier to see the posterior part of the drum than the anterior part. The canal may be partly straightened by pulling the pinna backwards and upwards during examination. In infants pull the pinna more horizontally backwards as the shape of the ear canal is different. In addition, the angle of the drum may appear different in small children, with the top of the drum appearing more lateral than the inferior part./ Note the appearance of the ear canal including it's diameter and the presence of wax. It is usual to see some wax in almost every ear.
/ Larger deposits may obscure the view of the drum, but this does not necessarily imply that the wax is causing deafness. The canal needs to be almost completely obstructed to case hearing loss.
/ Wax is not normally present in the inner third of the ear canal. It's presence there may indicate inappropriate use of cotton buds to clean the ears of it may be a dried up crust, overlying more significant pathology such as a perforation or cholesteatoma
/ In otitis externa, an infective / inflammatory condition, the canal may be so swollen that a view into the ear is impossible
/ In swimmers, divers and surfers, chronic cold water exposure can lead to the growth of bony swellings in the canal known as exostoses. These are generally asymptomatic when small, but when larger can interfere with the drainage of wax and predispose to infections such as otitis externa
/ These black dots (spores) are the appearance of fungal infection (aspergillus niger) with other fungi the spores may be white or yellow
/ This is chronic otitis externa. Although the canal wall is not swollen, the skin is excoriated and red. The drum is essentially normal.
/ Foreign body in the canal of a child (wax crayon) note the drum visible distal to the foreign body
The Normal Eardrum
Normal Eardrum
/ Normal right eardrum, annotated version appears below/ see below for annotations
An annulus fibrosus
Lpi long process of incus - sometimes visible through a healthy translucent drum
Um umbo - the end of the malleus handle and the centre of the drum
Lr light reflex - antero-inferioirly
Lp Lateral process of the malleus
At Attic also known as pars flaccida
Hm handle of the malleus
There is no substitute for looking at as many drums as you can to give you an idea of what is normal and what is abnormal. Look in your fellow students ears to start with.
Shape of the eardrum
The drum is slightly convex being most medial at the end of the malleus handle or umbo. Abnormalities of shape are important, the drum may be bulging our, suggesting increased middle ear pressure, such as in acute otitis media, or retracted inwards with negative middle ear pressure, which is one of the otoscopic findings in glue ear.
/ Mild retraction may be difficult to identify. The margin of the drum (annulus may become more pronounced as in this image/ As the drum retracts so does the handle of the malleus and it may appear to be shortened on otoscopy. The lateral process will also become much more prominent than normal
/ As the drum becomes increasingly retracted, it drapes over the ossicular chain, and the incus and stapes head may be outlined
/ Eventually, nearly all the middle ear space may be lost and the drum comes into contact with the medial wall of the middle ear (this is known as atelectasis)
Bulging ear drums are usually fairly obvious and a result of increased middle ear pressure. The most likely cause of this is acute otitis media when the drum will not only bulge outwards, but is usually very red because of hyperaemia and infection. Unfortunately I have found good images of acute otitis media hard to come by because the patients are usually very young and not over disposed to sit still to have pictures taken!
Color of the Drum
The normal drum is quite translucent and does not really appear to be any color except perhaps grey. The color of the drum can be changed by thickening of the drum itself, injection of blood vessels, or the presence of something behind it such as glue, pus or blood.
/ Compare this drum with the normal one. It is opaque and pale. There is slight injection of blood vessels. This is one appearance of glue ear/ Glue ear may make the drum yellow or even darker than normal. Note also how retracted this drum is and how prominent the lateral process of the malleus appears. Blood in the middle ear will give the ear a blue or brown colour, this is called a haemotympanum.
/
Bubbles
You may see bubbles behind the drum. This represents a resolving middle ear effusion, as air gradually re-enters the middle ear./ In this image, the bubbles appear much larger
/
White patches
white patches actually on the drum or within the drum itself are usually tympanosclerosis, which is deposition of calcium into the drum itself in response to trauma or infection. This is not normally of any consequence unless it is severe, which can lead to a mild conductive hearing loss./ If the white patch is behind the drum, this may represent cholesteatoma (keratin in the middle ear). This normally needs to be treated surgically.
Red / blue Lesions on the drum
A diffusely red drum usually represents otitis media. More localised areas of discoloration can represent infection or vascular abnormalities behind the drum./ This small red lesion at the tip of the malleus handle is a vascular lesion called a glomus tumour. This might cause pulsatile tinnitus, but is rare. This needs surgical treatment.
/ This red bulge in the canal is another glomus tumour (glomus jugulare). this is the tip of a much larger lesion involving the temporal bone.