A system of practical medicine. By American authors. Vol. 3

by Unknown

Sunlight is certainly the best source of light for the illumination of the interior of the larynx and nasal cavities, but, unfortunately, it is not available at all times and in all localities. When it can be obtained, however, the student should not neglect the opportunity, and should not be deterred from using it for examination by the little extra apparatus and trouble necessary.

The most convenient plan is to place a small plane mirror mounted upon a stand in such a manner that it can be turned in any direction, such as a small toilet-glass, in the direct rays of the sun coming through a southern window. Then turn the mirror until the reflection falls upon a second plane mirror supported by a jointed arm and placed in a distant corner of the room, and in front of the chair upon which the patient is seated, with his back to the first mirror. The light from the second mirror is then thrown into the patient's mouth in the same manner as when a light concentrator is used. The second mirror may also be mounted on the head band and used as a head reflector, but this latter plan is not as satisfactory, because the reflected light from the first mirror is apt to strike the observer's eye and temporarily blind him.

Sunlight, as well as the light from the oxyhydrogen and electric-arc lamps, is white, and therefore shows us the parts in their natural coloring, which is claimed as a great advantage over all other sources of light. It is true that the yellow rays which are predominant in all other artificial lights make the mucous membrane appear redder than it really is, and the observer may be led to believe that a congestion exists if the patient be examined by white light first, and then by yellow light on different occasions. But as all our knowledge and appreciation of shades of color depend upon a comparison with a standard, it makes no difference whether this standard, as in the case before us, is a little redder when viewed by yellow light or not so red when seen by white light. This advantage of the white light is, therefore, not of much practical value, and the expense and difficulties connected with the use of the oxyhydrogen or electric arc-light for laryngoscopy fully outweigh any advantage which can be claimed for it.

THE ART OF LARYNGOSCOPY.—Before entering upon a description of the details of the art it will be necessary to clearly understand the optical principle upon which the use of the laryngoscope is based, and, further, to remember that the object to be viewed is situated below the straight path of light and vision. The optical law referred to is, that "The angle of incidence is equal to the angle of reflection," and consequently, in order to illuminate the cavity of the larynx and to see its details, the laryngeal mirror must be placed in such a position in the fauces that the light is reflected downward. The light rays forming the laryngeal image will then be reflected from the surface of the laryngeal mirror into the eye of the observer. It should always be borne in mind that the image seen in the mirror is a reflected one, like the image of one's self seen in a looking-glass, so that what appears to be right is left, and vice versâ. On account of the difference in height of the parts forming the image, and because the mirror must be placed above and slightly behind the opening of the larynx, the picture appears reversed in an antero-posterior direction. The same holds good when viewing a drawing of a laryngeal image.

POSITION OF PATIENT AND OBSERVER.—The relative positions of the patient, observer, and the source of light are of very great importance, especially to the beginner, and a want of proper adjustment will often make it extremely difficult, if not impossible, to obtain the desired view of the larynx. The patient having been seated upon a chair, or better still upon a piano-stool, the source of light is placed upon a table at his right, at such a height that the centre of the flame is on a level with his eyes and a few inches behind. The observer then takes a seat directly in front of the patient, and, separating his knees, places his feet on either side of those of the patient, thus being able to grasp the patient's knees with his own should occasion require him to do so. This position is preferable to the one in which the knees of the observer are either on one side or the other of the patient's knees, because then the observer, in order to throw the light from the head mirror into the mouth of the patient, has to assume a constrained position which very soon becomes fatiguing. Under no circumstances should the patient be allowed to grasp the observer's knees, for then the latter is powerless to restrain the struggles of his patient, and cannot quickly leave his seat should vomiting occur. When the examination is made at the physician's office or wherever it is practicable, it is of advantage to have a head-rest, such as photographers use, for the patient's head.

The positions having been taken, the observer places the head reflector upon his forehead a little above the left eye, and by rotating it upon its ball-and-socket joint reflects the light from the lamp- or gas-flame upon the patient's face so that the circle of light is bounded above by the tip of the nose and below by the tip of the chin. It is of great importance that the adjustment of the reflector should be made by means of its joint, and not by rotating or inclining the head, for it is necessary that the head should have an easy position which can quickly be resumed should it become necessary to move the head. It requires considerable practice to quickly reflect the light from the head mirror in any desired direction, and it is therefore well for the beginner to practise this by throwing the light upon a spot on the wall before he attempts to examine a patient, as he will thus save himself, as well as the patient, unnecessary annoyance. If a light concentrator be used which supports the reflector on the jointed arm, this of course is not necessary, but the practice with the head mirror will even then be found advantageous, because when a patient is to be examined in the sick room a light concentrator cannot usually be employed, and the physician has to fall back upon the head mirror for illuminating the laryngeal cavity.

When the reflector has thus been properly adjusted the patient is required to incline his head backward and open his mouth as wide as possible, when it will be found that the centre of the circle of light falls upon the root of the uvula. A careful examination of the oral cavity, the anterior and posterior pillars, the tonsils, and the wall of the pharynx should be made before the laryngeal mirror is introduced, not only because the condition of these parts often imparts valuable information, but also in order to be sure that no infectious sores be present which might contaminate the instruments to be introduced. The laryngologist cannot be too careful to prevent the carrying of infectious material from one patient to another; and if he should by this preliminary examination discover a specific sore, he should use only such instruments as are reserved for this class of cases, and which are kept in a separate box or drawer of the instrument-case.

Everything being in readiness, the laryngeal mirror is held over the lamp, with the glass side down, for a few seconds until it is warm, so as to prevent the condensation of moisture on its reflecting surface, and is then introduced in the following manner: The handle is held between the thumb and fore finger of the right hand like a pen-holder (Fig. 4); the hand is bent backward upon the wrist and held below the chin of the patient. Meanwhile, the protruded tongue is grasped between the folds of a napkin or towel held in the left hand, and gently but firmly pulled out of the mouth. Great care should be exercised to prevent the frænum of the tongue from coming in contact with the sharp edge of the front teeth, for this soon becomes very painful and may prevent a successful examination. Many laryngologists are in the habit of letting the patient hold his tongue, which becomes necessary when operations or applications are to be made to the larynx; but for the purpose of examining only it is better for the observer to hold the tongue, as he thus gains more control over the movements of the head of the patient.

FIG. 4.

Position of Hand in holding the Laryngeal Mirror.