Sutugin (Sammlung Klin. Vorträge, No. 310) makes an important
contribution to the knowledge of this subject. The paper deals with an
“almost wholly neglected factor in the mechanism of labor,” namely, the
position of the fœtal trunk in utero, the mechanism of the trunk
movements and their effect upon the positions of the head during labor.
He first shows that the views commonly accepted with reference to the
position of the fœtal trunk during pregnancy are in part erroneous.
Observations by the author in six hundred and sixty cases, published in
1875, established the fact that before labor, in either right or left
positions, the dorsum of the child is almost invariably turned to the
mother’s back, the vertebral column of fœtus, as a rule, lying but
little to one side or the other of the spinal column of the mother; and,
furthermore, the changes of position during pregnancy, as from right to
left, probably take place by rotation along the posterior wall of the
uterus. On the occurrence of energetic uterine contractions, especially
at the beginning of labor, the back of the child is sometimes rotated to
the mother’s side. Kehrer has confirmed the conclusions of Sutugin in
observations upon certain of the lower animals. It may be noted in
passing that, according to Kehrer’s observations, gravity is a
subordinate factor in determining the attitude of the fœtus in utero.
The author of the paper declares that, in a large number of cases
examined during the last twelve years he has not in a single instance
found the back of the child turned wholly forward during pregnancy, not
even in first positions of the head. He has more recently made a study
of the varying positions of the trunk during labor. Early in the labor,
in first positions of the head, the trunk rotates so that the back of
the child looks sideways, the shoulders lying in a plane parallel with
the introitus. The breech rotates more slowly than the shoulders, the
spinal column of the child thus assuming the form of a spiral during
delivery. The fœtus, therefore, in its descent moves in a screw-like
direction around its own axis, but the back of the child is not turned
forward even during parturition, as authors generally have assumed.
These views are born out by the frozen sections of Chiara, Waldeyer, and
Shroeder. The rotation of the head is in part due to the rotation of the
trunk, “the torsion of the axis of the fœtus,” and is not to be referred
solely to the action of the pelvic planes. The author claims that a
torsion of the uterus upon its axis similar to that of the child also
occurs. With reference to the etiology of the torsion in case of uterus
or fœtus, he ventures no explanation.