Otoscopy

OTOSCOPY, one of the most important methods of ear examination, by which the external auditory meatus, the tympanic membrane, and, in the event of the destruction of the latter, the middle ear as well, are directly inspected. To perform otoscopy, it is necessary to have an illumination device. The latter are divided into illuminators providing direct light (Clar's lamp) and illuminators with reflected light. Otologists use the latter instruments almost exclusively. Among them, the frontal reflector (see Otorhinolaryngological Instruments) is the most convenient. By means of a strap, the reflector is fastened to the head and aimed at the right or left eye in such a way that its central aperture coincides with the pupil of the eye. It is also possible to use a reflector attached to a handle held in the hand or between the teeth. For prolonged examinations or surgical interventions, the latter reflectors are unsuitable. Daylight or artificial light may serve as the light source in otoscopy. In the first case, one has to use the diffused light of white clouds, because sunlight gives too bright a light and generates significant heat. Daylight has the advantage that the more natural color of the tympanic membrane is visible under it. For a more detailed examination, it is better to use artificial light—a kerosene or electric lamp. To make the light source have a more uniform surface, frosted incandescent bulbs and special projectors equipped with a system of lenses have been proposed (see Otorhinolaryngological Instruments). The light source is placed to the right and somewhat behind the patient, while the physician is in front of the patient facing the light. The light source, the patient's head, and the examiner's head must be at the same height (see illustration). Otoscopy is best performed in a darkened room. The patient's head during otoscopy is turned toward the side opposite the ear being examined, approximately by 90°, so

that the longitudinal axis of the auditory meatus coincides with the direction of the light rays from the reflector. With two fingers of one hand, the auricle is pulled upward and backward to straighten the external auditory meatus. If the tragus is pushed aside with a finger of the other hand, it is frequently possible to inspect the external auditory meatus and even the tympanic membrane without any appliances. In cases of narrow auditory meatuses or for a more detailed examination, it is necessary to have an ear speculum (specula proposed by various authors—see Otorhinolaryngological Instruments). For studying the details of the tympanic membrane, ear loupes and ear microscopes (Voltolini, Trautmann, Weber-Liel, Lüscher) and photographing the membrane (Hegener's method) have been proposed. A very valuable instrument in otoscopy is Siegel's pneumatic speculum (Siegel), by means of which the degree of mobility of individual parts of the tympanic membrane, cicatricial changes on it, and thickenings are determined. The ear speculum is inserted into the auditory meatus with rotational movements of two fingers of the right hand, to a depth of approximately 1 to 1.5 cm. The introduction of the speculum into the osseous part of the auditory meatus is painful and unnecessary, since obstacles are encountered most frequently in the cartilaginous part of the auditory meatus. Obstacles to otoscopy in the external auditory meatus include foreign bodies (bedbugs, flies, cockroaches, seeds, peas, fruit stones), congenital and acquired pathological changes (exostoses, atresias, cerumen and epidermal plugs, furuncles, diffuse inflammatory processes, polyps, and neoplasms). In cases of exostoses and incomplete atresias, however, inspection of the tympanic membrane is possible with the aid of very narrow ear specula. Foreign bodies, cerumen, and epidermal plugs must be preliminarily removed by irrigation or with appropriate instruments. Inflammatory processes in many cases require prior treatment, and only then is it possible to introduce the speculum and view the tympanic membrane.

Otoscopic picture. 1. The external auditory meatus in a normal adult has the appearance of an oval channel about 3.5 cm long, terminating at its inner end in the tympanic membrane. In the cartilaginous part, the channel curves forward and downward. At the site of transition of the cartilaginous part into the osseous part, a narrowing of the auditory meatus is noted (isthmus). Near the tympanic membrane, another narrowing of the auditory meatus is visible due to a bony eminence on the lower wall. The auditory meatus is lined with skin, which in the cartilaginous part is provided with hair follicles, ceruminous, and sebaceous glands. Pathological processes alter the skin color and the shape of the auditory meatus. Hyperemia of the skin is frequently encountered. Narrowing of the auditory meatus can be concentric and slit-like (upon drooping of the upper-posterior wall). 2. Otoscopy of the tympanic membrane—see Tympanic membrane, methods of examination.

A. Helfand.