The ischial spines is zero (0) station.
(5) Below the ischial spines is referred to +1 to +5, indicating the lower the
presenting part advances.
Figure 10-3. Measurement of station.
e. Engagement. This refers to the entrance of the presenting part of the fetus
into the true pelvis or the largest diameter of the presenting part into the true pelvis. In
relation to the head, the fetus is said to be engaged when it reaches the midpelvis or at
a zero (0) station. Once the fetus is engaged, it (fetus) does not go back up. Prior to
engagement occurring, the fetus is said to be "floating" or ballottable.
f. Position. This is the relationship between a predetermined point of reference
or direction on the presenting part of the fetus to the pelvis of the mother.
The maternal pelvis is divided into quadrants.
(a) Right and left side, viewed as the mother would.
(b) Anterior and posterior. This is a line cutting the pelvis in the middle
from side to side. The top half is anterior and the bottom half is posterior.
(c) The quadrants never change, but sometimes it is confusing
because the student or physician's viewpoint changes.
NOTE: Remember that when you are describing the quadrants, view them as the