Otoscopy (Ear examination)

Otoscopy (Ear examination)

What is the definition of otoscopy?

Anomalies spotted during an otoscopy may involve earwax obstructing the eardrum.

Otoscopy entails examining the ear using a tool known as an otoscope (or auriscope).

This examination aims to scrutinize the 'external auditory canal,' the passage extending from the outer ear (pinna) to the eardrum.

Assessment of the eardrum can also yield substantial insights into the conditions prevailing within the middle ear, where the auditory and balance mechanisms are housed.

An otoscope typically comprises three components:

- the handle, housing the power for the light source
- the head, containing the light bulb and magnifying lens
- the cone, inserted into the ear canal.

External ear inspection

Before inserting the otoscope cone into the ear canal, the outer ear is examined for any indications of ailments relevant to the patient's symptoms. For instance, if the complaint involves ear pain, signs of outer ear infection like redness or slight swelling might be present.

External auditory canal examination

This examination involves gently pulling the outer ear upward and backward to straighten the natural curvature of the external auditory canal, facilitating eardrum visualization.

A normal external auditory canal typically hosts some hair, often accompanied by yellow to brown wax. In adults, the ear canal's total length is approximately 2cm, providing a resonance frequency crucial for speech comprehension, around 3400 Hz.

Abnormal observations may include

- a dry, flaky lining indicative of eczema, often accompanied by itching
- an inflamed, swollen, narrowed canal, potentially with discharge suggesting infection (otitis externa). Symptoms may include itch, local discomfort, discharge, and sometimes a foul smell from the ear.
- earwax obstructing the eardrum
- presence of a foreign body in the ear, such as eraser rubber.

Eardrum examination

A normal eardrum typically appears pinkish-grey and circular. The first of the three small bones transmitting sound vibrations to the cochlea lies against the far side of the eardrum and may be visible through it in the upper part, resembling clock hands at approximately 12 o'clock.

Many otoscopes feature a small air vent for insufflation, allowing assessment of eardrum mobility by observing its response to air pressure variations, which depend on middle ear pressure.

Under normal conditions, middle ear pressure equals outer ear pressure, enabling optimal eardrum positioning for efficient sound vibration transmission.

Eustachian tube blockage, common in conditions like hay fever, colds, or glue ear in children, can impair hearing or cause pain due to pressure differences.

The Valsalva maneuver, involving gently blowing out while pinching the nose and closing the lips, can provide insight into Eustachian tube functionality. A normal response involves slight eardrum movement; lack of movement suggests Eustachian tube blockage.

Other abnormal findings with the otoscope may include

- eardrum perforation, which can heal remarkably well depending on the cause
- acute middle ear infection (acute otitis media), characterized by red or yellow eardrum appearance with indistinct landmarks and reduced mobility during insufflation.
- Occasionally, acute otitis media may cause eardrum perforation, relieving pressure and pain and resulting in visible tear and discharge, which typically heals completely in most cases.