Correct Otoscopy: Technique, Common Findings, and Choosing the Right Otoscope

1. Basics of Otoscopy

Otoscopy involves the visual inspection of the external auditory canal (meatus acusticus externus) and the tympanic membrane (membrana tympani) using an illuminated instrument. It is an integral part of every general and pediatric examination and provides vital diagnostic information within seconds.

Anatomical Basics

Knowledge of anatomical landmarks is essential for accurate diagnosis:

• External Auditory Canal: About 2.5 cm long in adults, S-shaped. The cartilaginous portion (lateral third) is movable and contains ceruminous glands; the bony portion (medial two-thirds) is sensitive to pain.
• Tympanic Membrane: Semitransparent membrane, oval, slightly inward concave (umbo). Pars tensa (tense part) and pars flaccida (Shrapnell membrane) must be differentiated.
• Light Reflex: The light reflex (light cone) projects forward-downward onto the healthy tympanic membrane (at 5 o'clock on the left, 7 o'clock on the right).
• Handle of Malleus (Manubrium mallei): Visible as stria mallearis through the tympanic membrane, central orientation structure.

2. Preparation and Patient Positioning

Careful preparation is a prerequisite for a meaningful examination. The following steps should be routinely followed:

Selection of Ear Trays (Specula)

Always choose the largest possible specula that comfortably fits into the ear canal. A specula that is too small unnecessarily restricts the field of view and increases the risk of injuring the canal. Common sizes:

• 2 mm: Newborns and infants
• 3 mm: Toddlers (1–3 years)
• 4 mm: School-age children and teenagers
• 5 mm: Adults (standard size)

Patient Positioning

Adults: Seated, head tilted slightly to the opposite side. The examiner stands or sits at eye level with the ear to be examined.

Children: Toddlers are best examined while sitting on a caregiver's lap, with the head held sideways against the caregiver’s chest. The caregiver secures the child’s arms with their other arm. For uncooperative children, positioning in a supine position with the head turned sideways is an option.

3. Examination Technique Step by Step

Inspection and Palpation

Before inserting the otoscope, always inspect the auricle (auricula) and the mastoid region. Look for:

• Redness, swelling, or eczema of the auricle
• Pain on tragus pressure (indicative of otitis externa)
• Pain on mastoid percussion (indicative of mastoiditis)
• Retroauricular swelling or fistula formation

Correct Handling of the Otoscope

Handling the otoscope correctly is crucial for a pain-free and complication-free examination:

1. Grip: Hold the otoscope like a pencil between thumb and forefinger, with the handle pointing upwards or sideways. Alternatively: inverted grip (handle down), especially for children.
2. Bracing: The fingers of the holding hand must brace against the patient's face. This prevents injury from sudden head movements – a critical safety aspect.
3. Straightening the Ear Canal: Grasp the auricle with your free hand: pull upward and backward for adults, backward and downward for children under 3 years.
4. Insertion: Slowly and carefully insert the specula into the cartilaginous portion of the auditory canal under visual control. Never advance blindly or beyond the cartilaginous-bony transition.
5. Systematic Inspection: Assess the entire circumference of the ear canal, then systematically inspect the tympanic membrane.

Systematic Tympanic Membrane Evaluation

Assess the tympanic membrane using the CLIF schema:

• C – Color: Normally pearly gray, semitransparent
• L – Light reflex: Sharply demarcated, triangular
• I – Integrity: Intact, no perforations or retractions
• F – Fluid: No effusion, no air-fluid level

4. Common Otoscopic Findings

Cerumen Obturans

Cerumen is the most common reason for restricted visibility of the tympanic membrane. Before evaluation, the canal must be cleaned – either by irrigation (caution: only with intact tympanic membrane), suctioning, or instrumental cleaning under visualization using hooks or curettes.

Otitis Externa

Typical findings: redness of the ear canal, swelling, discharge (serous to purulent), pain on tragus pressure. Otoscopy may be painful – gentle handling and, if necessary, prior topical analgesia is recommended.

Acute Otitis Media (AOM)

Otoscope signs include:

• Bulging of the tympanic membrane
• Redness and opacity
• Absence or alteration of the light reflex
• Purulent discharge in case of perforation

Serous Otitis Media (Middle Ear Effusion)

Typical are amber coloration of the tympanic membrane, air-fluid levels, restricted mobility with pneumatic otoscopy, and retracted tympanic membrane position with prominent handle.

Tympanic Membrane Perforation

Perforations may be central, marginal, or edge-located. Marginal perforations in the pars flaccida region are clinically particularly relevant as they may be associated with cholesteatomas.

5. Peculiarities in Children

Otoscopy in children poses special requirements for the examiner and the equipment. The child's ear canal is narrower, shorter, and less S-shaped than in adults. Additionally, compliance, especially in toddlers, is often limited.

Age-Appropriate Access Technique

• Infants (0–12 months): Pull the auricle backward and downward. Use 2-mm specula. Examine in supine position with head turned to the side.
• Toddlers (1–3 years): Pull the auricle backward and downward to backward and straight. Use 3-mm specula. Secure on the caregiver’s lap.
• School-Aged Children (from 4 years): As with adults, pull upward and backward. Use 4-mm specula. Encourage cooperation by child-friendly explanations.

Pneumatic Otoscopy

Pneumatic otoscopy is the gold standard for assessing tympanic membrane mobility and thus differentiating between acute otitis media and middle ear effusion. For this, an otoscope with a sealing specula and a side pressure balloon or tube is used. A mobile tympanic membrane argues against significant middle ear effusion.

6. Criteria for Choosing the Right Otoscope

The quality of otoscopy is directly dependent on the quality of the instrument used. When purchasing an otoscope, consider the following criteria:

Lighting Technology

• Direct Light (Halogen): Conventional technology with a light source inside the otoscope head. Inexpensive, but the light source causes shadows, and color rendering may be limited.
• Fiber Optic (XHL/LED): Light is transmitted through fiber bundles, providing uniform, shadow-free illumination at the tip of the specula. Far better illumination and color rendering. Standard in modern practice.
• LED: Latest technology with excellent color temperature (close to daylight), long lifespan, and high energy efficiency. Optimal for assessing tympanic membrane color and transparency.

Optical Magnification

Common otoscopes offer a 2.5- to 4-fold magnification. Higher magnification allows for more detailed assessment of the tympanic membrane but reduces the field of view. For general practice, a 3-fold magnification is a good compromise.

Power Supply

• Battery-Operated (AA/AAA): Universal, immediately replaceable, no charging time
• Rechargeable Battery (NiMH/Li-Ion): More cost-effective in operation, provides constant light intensity over the charging period, but requires charging time
• USB-C Charging: Latest variant, compatible with common charging cables

Other Criteria

• Pneumatic Connection: Necessary for pneumatic otoscopy
• Specula System: Disposable vs. reusable specula, size selection
• Ergonomics: Weight, grip design, balance
• Durability and Serviceability

7. Otoscope Comparison: Direct Light vs. Fiber Optic vs. Video

8. Common Mistakes and How to Avoid Them