It is necessary to be certain that the axis of the bronchoscope corresponds to the axis of the trachea, in order to avoid injury to the subglottic tissue which might be followed by subglottic edema (Fig. 47). If the subglottic region is already edematous and causes resistance, slight rotation to the laryngoscope, and bronchoscope will cause the bronchoscope to enter more easily. [FIG. 59.--Insufflation anesthesia with Elsberg apparatus. Anesthetist has exposed the larynx and is about to introduce the silk-woven catheter. Note the full extension of the head on the table.] [FIG. 60.--Schema illustrating the introduction of the bronchoscope through the glottis, recumbent patient. The handle, H, is always horizontally to the right. When the glottis is first seen through the tube it should be centrally located as at K. At the next inspiration the end B, is moved horizontally to the left as shown by the dart, M, until the glottis shows at the right edge of the field, C. This means that the point of the lip, B, is at the median line, and it is then quickly (not violently) pushed through into the trachea. At this same moment or the instant before, the hyoid bone is given a quick additional lift with the tip of the laryngoscope.] [FIG. 61.--Schema illustrating oral bronchoscopy. The portion of the table here shown under the head is, in actual work, dropped all the way down perpendicularly. It appears in these drawings as a dotted line to emphasize the fact that the head must be above the level of the table during introduction of the bronchoscope into the trachea. A, Exposure of larynx; B, bronchoscope introduced; C, slide removed; D, laryngoscope removed leaving bronchoscope alone in position.]