AUTO-LARYNGOSCOPY.—There is perhaps no better method for the beginner to overcome the difficulties besetting laryngoscopy than to practise the art on himself, for then only will he be able to appreciate to its full extent the necessity of observing all the minute details described above, as the pain and inconvenience which he inflicts upon himself by his false movements will teach him better, and enable him to attain proficiency in the use of his instruments quicker than any other method of practice. Nothing need, for auto-laryngoscopy, be added to the stock of instruments necessary for the examination of others, except a stand to which the reflector is fastened and a small toilet-mirror. The observer seats himself beside a table upon which, at his left, is placed the lamp a little behind his head and the centre of the flame on a level with his eyes. The stand, an ordinary retort-stand, is placed in front of him, and to it is fastened at the proper height the reflector. On the same stand, and immediately above the reflector, is attached the plane mirror in such a manner that it can be inclined at an angle. Inclining the head slightly backward, the observer then by watching his face in the plane mirror directs the light upon his mouth by moving the reflector upon its ball-and-socket joint until the circle falls upon his mouth. He then opens his mouth as wide as possible, grasps his protruded tongue between the folds of a towel or napkin held between the thumb and fore finger of the left hand, and introduces the laryngeal mirror with the right hand in the manner described above. The laryngeal image as it appears on the surface of the laryngeal mirror is reflected by the toilet-glass above the reflector, and can be seen in all its details by the person practising auto-laryngoscopy. By substituting a perforated mirror for the toilet-glass the student can demonstrate the image to others in his own person if the observers look through the perforation in the mirror.
Before giving a description of the laryngeal image it will be well, for the sake of completeness, to mention the fact that of late photography has been employed to reproduce this image, both in this country by T. R. French of Brooklyn17 and by Lennox Browne of London, England, with very gratifying results. The writer himself several years ago made experiments in this direction, which, however, were not very satisfactory in their results. The method employed by French is a very simple one, and it will be best to give his own description of the process:
"The camera consists of a box 4½ inches long, 17/8 inches wide, and ¾ of an inch in thickness. The back opens upon hinges, and admits of the introduction of either the ground glass or the plate-holder. On the anterior face a tube 11/8 inches long is attached, in the outer end of which the lens is placed. This lens has a focus of 1¼ inches. At the side of the tube a part of the handle of a throat mirror is fixed, and into that the shank of the throat mirror is passed and fastened by a thumb-screw. The shank of the mirror is somewhat curved, and is attached to the side of the frame holding the mirror. The object of this is to allow the lens being held opposite any part of the opening of the mouth, and also to prevent the possibility of a shadow being cast upon the mirror. In the front part of the box is a shutter made of lead and perforated with a hole just the size of the lens. The shutter is held in position by a lever acting as a key on the anterior face of the camera.
"The apparatus is used in the following manner: A reflector, either plane or concave, attached to a head band, is arranged over the left eye so that the pencil of sunlight from the solar condenser is received upon it and thrown into the mouth. The patient, with the head inclined slightly backward, now protrudes the tongue and holds it well out between the fore finger and thumb of the right hand. The throat mirror with the camera attached, held in the right hand of the observer, is placed in position in the fauces, and the light adjusted so that the larynx can be seen with the observer's left eye to be well illuminated. If, now, the tongue does not mount above the level of the lower edge of the lens and the lower edge of the mirror, it may be taken for granted that when the plate is exposed the picture received upon it will be nearly the same as that seen with the left eye in the throat mirror. The photograph is taken by pressing upon the key with the index finger; this releases the shutter, which in falling makes an instantaneous exposure amounting to perhaps one-seventh of a second.
"In using condensed sunlight with a small camera it is important to throw the circle of light from the inner side of the reflector, that nearest the nose; for in this way a part of the larynx exposed to the lens of the camera may be illuminated which cannot be seen with the eye. To ensure this it is best to cover the outer half of the reflector with black silk. On account of the parallax or displacement of the image due to the difference in point of view between the eye and the camera, some skill is necessary in managing the illumination so that the part which it is desired to bring out will be exposed to the lens if not to the eye."
17 Archives of Laryngology, vol. iv. No. 4.
THE LARYNGEAL IMAGE.—When the mirror is introduced and is held in the proper place, and the light is reflected downward, the laryngeal image will appear on the surface of the mirror. As it is, however, so different from what might be expected after having examined a larynx removed from the body, it requires a detailed description, and the student will do well to refer to the diagrams frequently while examining patients, to make himself familiar with the details he sees, and to recognize them when they are altered by disease or when they are slightly different in shape in different individuals. Figs. 7 and 8 represent the image of the larynx in the act of respiration and of phonation as it appears on the surface of the mirror, while Figs. 9 and 10 are diagrammatic, and are intended to represent the same.
| FIG. 7. |
| Laryngeal Image during Respiration. |