The otoscope is one of those basic tools that any doctor has to know how to use. Although they may seem specific instruments of a specialist, the otolaryngologist, all physicians must have the basic ability to use it and know how to interpret the findings they find when exploring the ears of their patients. For this reason, it is important to have a clear idea of what an otoscope is, what it is for, what we can expect from it and how to handle it efficiently.
In case you want to buy one, this knowledge will be useful to have enough criteria to know your needs and decide which one you want to choose. It is not necessary to be a specialist in ear pathology, but it is important to know what a normal ear is like and have a simple strategy to detect the most frequent anomalies.
Anatomy of the ear
Before proceeding with the examination, it is important to have a clear idea of the anatomy involved in the otoscopy.
It is formed by elastic cartilage covered by skin. It has a helical shape that forms a funnel towards the center. This serves to direct the sound waves towards the auditory canal.
External auditive conduct
It measures between 2-5 centimeters in length and 7 mm in diameter in adults. It goes from the shell of the auricular pavilion to the eardrum. During its journey, we found hairs and sebaceous glands. The hairs are usually short and irritable against foreign bodies, and the sebaceous glands produce cerumen (wax) that protects the ear from infections and foreign bodies. The path of the external auditory canal is not straight but has the shape of that italic. That’s the reason why you have to pull the ear up and back during the scan: to have a direct view of the eardrum.
The eardrum is at an angle to the canal and creates an anteroinferior hole in which foreign bodies can accumulate. The tympanic membrane is semitransparent, oval, pearly gray, pink and pale. The end of the external bony auditory canal is located obliquely.
The tympanic membrane consists of:
- Flaccid pair.
- Pars tense.
- Hammer handle: in the middle part of the tense pars.
- Lateral process of the hammer or short process of the hammer: in the upper part of the handle
- Umbo (navel)
- Annulus fibrosus
- Luminous cone.
The cone of light is located in the anterior-inferior quadrant. It originates through the direct reflection towards the retina of the observer of the luminous rays that impinge on a segment of the membrane perpendicular to the visual axis. It is important to identify and know these normal components as this will make it easier for us to recognize any pathological changes.
How to handle the otoscope
Before proceeding, there are always some important preparations :
- Introduce yourself to the patient.
- Ask your name, age or reason for consultation.
- Do the anamnesis.
- If you decide that you have to explore the ear, explain the procedure to the patient and clarify doubts before proceeding with the examination.
- Wash your hands.
- Prepare the material you need. Assemble the otoscope
- Choose a suitable cone for the patient and place it on the otoscope. In children, it will be smaller.
- Check that the otoscope works, that is, that it gives light and that you can visualize it.
- The purpose is to observe the outer ear and the tympanic membrane.
Inspection of the auricular pavilion
Pay attention to the normal anatomy I identify the helix, antihelix, Trago, Santiago, the shell and the lobe.
Use the light as a flashlight to explore the auditory pinna and identify any alteration that does not correspond to the normal: deformities, injuries, previous surgical wounds. Rests of suppuration or blood, eczema over the whole meatus.
In the second place, making the palpation of the pinna. Is there any traction pain or mobilization of the auricle? Is there edema of the ear? Is your temperature increased? Is there any alteration in the coloring? Do you palpate adenopathies around the ear?
How to hold the otoscope?
There are two ways:
- As if it were a hammer.
- As if it were a pencil or pen.
It is recommended to grasp the otoscope as if it were a pencil or pen. Attached between the index finger and thumb supporting the ulnar side of the hand on the cheek or the patient’s temple. This allows the side of your hand that rests on the patient to reduce the risk of a stroke if the head suddenly moves. This is more likely in children. In changes, holding the handle as if it were a hammer may seem more natural, but you have less control and it is easier to hurt with sudden movements of the patient and pressures more than the external ear canal. As I comment, it is advisable to train to grip the handle of the otoscope as a pencil or pen.
With what hand is the otoscope held?
Hold the otoscope in your hand on the same side of the ear that you will explore. If we are going to explore the right ear, we hold the otoscope with the right hand. If we are going to explore the left ear, we hold the otoscope with the left hand. Use your free hand to gently pull the auricle up and back to straighten the external auditory canal and align it with the eardrum. If it’s a child, we traced back horizontally. Everything will depend on the characteristics of the patient. Insert the cone gently through the auditory meatus and rest the outside of your hand against the patient’s temple.
What ear do we examine first?
Examine the asymptomatic ear first.
- You avoid passing an infection from one ear to another.
- You see first the anatomy of the normal ear and it will be easier to compare with the affected ear. So you can see if there are differences.
What do we look for during the otoscopic exploration of the ear?
We explore the external auditory canal and the eardrum systematically. We value based on the normal anatomical characteristics that we already know and I have mentioned before.
Can you see all the external auditory canal well?
It may be absent, stenotic, edematous, filled with wax, blood, or a foreign body. Pay attention to possible alterations in the skin: inflammation, swelling, remains of suppuration, or blood … Sometimes it can be interesting to clean the canal to visualize it better, but if you suspect that there may be a perforation, you should not use syringe cleaning because it can damage the middle ear. That case would have to be sent to the otolaryngologist.
Can you see the handle and the lateral process of the hammer?
Inspect the tense pars beginning with the posterosuperior quadrant and then move forward and down and back to 360 degrees. Inspect the pars flaccid. Identify the handle of the hammer resting on the eardrum. Look for the lateral process of the hammer. The normal thing is that on most of the occasions you visualize them. The exception maybe after some surgical interventions of the ear. Sometimes the accumulation of wax in the final part of the duct can give a darker appearance. The handle of the hammer can be visible even though most of the tense pars are absent and tells you where the eardrum should be.
Is the tympanic membrane intact?
Do not confuse a tympanic retraction with a perforation. The blood vessels of the middle ear mucosa can be visualized and will give you an indication that there is a perforation. Beware if you see, remains of whitish keratin on the edge of the tense pars and especially in the flaccid pars can lead to a hidden cholesteatoma.
Is the tympanic membrane of color and transparency correct?
A golden, bluish or opaque coloration usually indicates fluid in the middle ear. The white patches, as if they were chalk stains, on the eardrum are called tympanosclerosis. They are very frequent and are usually by previous surgery. They do not usually have clinical relevance.
Most frequent problems during otoscopy
Do not visualize well.
Check light, battery, or electrical connection. If the luminosity is not enough, you will not be able to see the nuances of the state of the eardrum.
You only see the conduit
Stretch the auricle a little further up and back to straighten the canal or move the otoscope a little.
I do not distinguish anything due to a great alteration of the anatomy
Try to locate the lateral process of the hammer as a reference. It is usually always visible and then it is easier to locate yourself.
I’m not sure if there’s a perforation
It is usually evident, but sometimes it can be confused with a tympanic retraction. Find the capillaries of the middle ear mucosa to confirm that there is a tympanic perforation. The pneumatophore can help you to confirm or not because it generates positive or negative pressure by moving the eardrum in case the eardrum is well.
End of the otoscope scan
Gently remove the cone from the canal.
You have to practice a lot to improve exploratory ability.