Laryngoscopy is the main kind of laryngeal research. The complexity of the method lies in the fact that the longitudinal axis of the larynx is located at a right angle to the axis of the oral cavity, because of which the larynx can not be inspected in the usual way. Inspection of the larynx can be performed either with the help of a laryngeal mirror (indirect laryngoscopy), in which the laryngoscopic picture is presented in the form of a mirror image or with the help of special directories for direct laryngoscopy.
For indirect laryngoscopy, flat laryngeal mirrors are used, similar to those used for posterior mirror epipharyngoscopy. To avoid fogging the mirror, it is heated on a sbyrit lamp with a mirror surface to a flame or in hot water. Before the introduction of a mirror into the oral cavity, its temperature is checked by touching the back metal surface against the skin of the back surface of the investigator's brush.
Indirect laryngoscopy is carried out in three positions of the examinee:
- In a sitting position with a slightly tilted forward trunk and a slightly deflected backward head.
- In Killian's position (1) for a better view of the posterior parts of the larynx. In this position, the doctor examines the larynx from below, standing in front of the subject on one knee, and he tilts his head downwards.
- In the position of Türk (2) for examination of the anterior wall of the larynx, at which the subject tilts his head, and the doctor examines from above, standing in front of him.
The doctor with his right hand takes the handle with the mirror fixed in it, like a writing pen, so that the mirror surface is directed at an angle downwards. The examinee opens his mouth wide and maximizes his tongue. The doctor I and III with fingers of the left hand grasps the tongue wrapped in a gauze and keeps it in the protruding state, at the same time the finger of the same hand lifts the upper lip for a better view of the examined area, directs a ray of light into the oral cavity and inserts a mirror into it. The rear surface of the mirror is pressed against the soft sky, pushing it backward and upward. When you insert a mirror into the oral cavity, you should not touch the root of the tongue and the posterior pharyngeal wall so as not to cause a pharyngeal reflex. The rod and handle of the mirror rest on the left corner of the mouth, and its surface should be oriented so that it forms an angle of 45° with the axis of the mouth. The luminous flux directed to the mirror and reflected from it, illuminates the larynx cavity. The larynx is examined with a calm and forced breathing of the subject, then with the phonation of the sounds "e" and "a", which contributes to a more complete examination of the epiglottis and larynx. When phonation occurs, the clamping of the vocal folds occurs.
The most frequent obstacle with indirect laryngoscopy is a pronounced pharyngeal reflex. To suppress it, there are some tricks. For example, the subject is asked to produce in the mind a countdown of two-digit numbers or, holding hands, pull them with all their might. It is also suggested that the subject should retain his own language. This technique is also necessary when the doctor needs to perform some manipulations in the larynx, for example, removal of the fibroid on the vocal fold.
With indomitable gag reflex, resort to an anesthetic of the pharynx and the root of the tongue. In young children, indirect laryngoscopy is almost impossible, therefore, if necessary, mandatory examination of the larynx (for example, with its papillomatosis) resort to direct laryngoscopy under anesthesia.
The laryngoscopic picture of the larynx with indirect laryngoscopy appears in a mirror image: the fore sections of the larynx, often covered by the epiglottis, are visible from above; The posterior sections, including the arytenoid cartilages and the inter-head space, are displayed in the lower part of the mirror.
Internal larynx with indirect laryngoscopy:
- Base of the tongue
- Epiglottic tubercle
- Epiglottic free edge
- Aryepiglottic fold
- Vestibular folds
- Vocal folds
- Laryngeal ventricle
- Arytenoid cartilage with corniculate cartilage
- Morgagni's cartilage
- Interarytenoid space
With indirect laryngoscopy, examination of the larynx is possible only with one left eye looking through the forehead of the frontal reflector (as is easily seen when this eye is closed). Therefore, all elements of the larynx are visible in one plane, although the vocal folds are located 1.5-2 inches below the edge of the epiglottis. The lateral walls of the larynx are visualized sharply truncated. Above, that is, in the front, one can see a part of the root of the tongue with the lingual amygdala (1), then a pale pink epiglottis (2), whose free edge rises in the background of the sound "and", releasing the cavity of the larynx for viewing. Immediately under the epiglottis in the center of its edge, one can sometimes see a small tubercle of the epiglottis (3), formed by the leg of the epiglottis. Below and behind the epiglottis, apart from the angle of the thyroid cartilage and commissure to the arytenoid cartilages, there are vocal folds (7) of whitish-pearly color, easily identifiable by characteristic trembling movements, sensitive to even a slight attempt at phonation.
Normally, the edges of the vocal folds are even, smooth; When they inhale they somewhat diverge; During a deep inspiration they diverge to the maximum distance and the upper tracheal rings become visible, and sometimes even the keel of the tracheal bifurcation. In the upper lateral regions of the laryngeal cavity above the vocal folds, pink and more massive folds of the vestibule are visible (6). They are separated from the vocal folds by the entrance to the ventricles of the larynx. The inter-head space (11), which is, as it were, the base of the triangular larynx slot, is limited to the arytenoid cartilages, which are visible in the form of two clavate thickenings (9) covered with a pink mucosa. During phonation, one can see how they rotate towards each other with their front parts and pull together the attached vocal folds. The mucous membrane covering the posterior wall of the larynx becomes smooth when the arytenoid cartilages divergent on inspiration; When pharyngeal when the arytenoid cartilages approach, it gathers into small folds. In some individuals, the arytenoid cartilages come together so closely that they seem to go over each other. From the arytenoid cartilages are directed upward and forward scoop-epiglottis folds (5), which reach the lateral edges of the epiglottis and together with it serve as the upper boundary of the entrance to the larynx. Sometimes, with the subatrophic mucosa, in the thickness of aryepiglottic folds, one can see small elevations above the arytenoid cartilages - these are the caracolar (santorinium) cartilage; Laterally, Vriesberg cartilages (10) are located.
The color of the mucous membrane of the larynx should be assessed in accordance with the history of the disease and other clinical signs, as it normally does not differ in consistency and often depends on bad habits and exposure to occupational hazards. In hypotrophic asthenic bodies, the color of the mucous membrane of the larynx is usually pale pink; In normostenics - pink; In persons of fat, full-blooded (hypersthenic) or smokers, the color of the mucous membrane of the larynx can be from red to bluish without significant signs of the disease of this organ. When exposed to occupational hazards (dust, a couple of corrosive substances), the mucous membrane acquires a lacquered shade - a sign of an atrophic process.