les of Position_.--As will be seen in Fig. 47 the
trachea and esophagus are not horizontal in the thorax, but their long
axes follow the curves of the cervical and dorsal spine. Therefore, if
we are to bring the buccal cavity and pharynx in a straight line with
the trachea and esophagus it will be found necessary to elevate the
whole head above the plane of the table, and at the same time make
extension at the occipito-atloid joint. By this maneuver the cervical
spine is brought in line with the upper portion of the dorsal spine as
shown in Fig. 55. It was formerly taught, and often in spite of my
better knowledge I am still unconsciously prone to allow the head and
cervical spine to assume a lower position than the plane of the table,
the so-called Rose position. With the head so placed, it is impossible
to enter the lower air or food passages with a rigid tube, as will be
shown by a study of the radiograph shown in Fig. 49. Extension of the
head on the occipito-atloid joint is for the purpose of freeing the
tube from the teeth, and the amount required will vary with the degree
to which the mouth can be opened. Whether the head be extended,
flexed, or kept mid-way, the fundamental principle in the introduction
of all endoscopic tubes is the anterior placing of the cervical spine
and the high elevation of the head. The esophagus, just behind the
heart, turns ventrally and to the left. In order to pass a rigid tube
through this ventral curve the dorsal spine is now extended by
lowering the head and shoulders below the plane of the table. This
will be further explained in the chapter on esophagoscopy. In all of
these procedures, the nose of the patient should be directed toward
the zenith, and the assistant should _prevent rotation of the head_ as
well as _prevent lowering of the head_. The patient should be urged as
follows:
"Don't hold yourself so rigid."
"Let your head and neck go loose."
"Let your head rest in my hand."
"Don't try to hold it."
"Let me hold it."
"Relax."
"Don't raise your chest."

[FIG. 47.--Schematic illustration of normal position of the
intra-thoracic trachea and esophagus and also of the entire trachea
when the patient is in the correct position for peroral bronchoscopy.
When the head is thrown backward (as in the Rose position) the
anterior convexity of the cervical spine is transmitted to the trachea
and esophagus and their axes deviated. The anterior deviation of the
lower thi