rachea, on either side of which are
the openings of the main bronchi. As the carina is situated to the
left of the midline of the trachea, the lip of the bronchoscope should
be turned toward the left, and slight lateral pressure should be made
on the left tracheal wall while the head of the patient is held
slightly to the right. This will expose the left bronchial orifice and
carina.

_Entering the Bronchi_.--The lip of the bronchoscope should be turned
in the direction of the bronchus to be explored, and the axis of the
bronchoscope should be made to correspond as nearly as possible to the
axis of this bronchus. The position of the lip is designated by the
direction taken by the handle. Upon entering the right bronchus, the
handle of the bronchoscope is turned horizontally to the right, and at
the same time the assistant deflects the head to the left.

_The right upper-lobe bronchus_ is recognized by its vertical spur;
the orifice is exposed by displacing the right lateral wall of the
right main bronchus at the level of the carina. Usually this orifice
will be thus brought into view. If not the bronchoscope may be
advanced downward 1 or 2 cm., carefully to avoid overriding. This
branch is sometimes found coming off the trachea itself, and even if
it does not, the overriding of the orifice is certain if the right
bronchus is entered before search is made for the upper-lobe-bronchial
orifice. The head must be moved strongly to the left in order to view
the orifice. A lumen image of the right upper-lobe bronchus is not
obtainable because of the sharp angles at which it is given off. _The
left upper-lobe bronchus_ is entered by keeping the handle of the
bronchoscope (and consequently the lip) to the left, and, by keeping
the head of the patient strongly to the right as the bronchoscopist
goes down the left main bronchus. This causes the lip of the
bronchoscope to bear strongly on the left wall of the left main
bronchus, consequently the left upper-lobe-bronchial orifice will not
be overridden. The spur separating the upper-lobe-bronchial orifice
from the stem bronchus is at an angle approximately from two to eight
o'clock, as usually seen in the recumbent patient. A lumen image of a
descending branch of the upper-lobe bronchus is often obtained, if the
patient's head be borne strongly enough to the right.

[FIG. 65.--Schema illustrating the entering of the anteriorly
branching middle lobe bronchus. T, Trachea; B, orific