Hodge planes are levels used to imaginably divide the pelvis from the upper strait to the lower strait in order to locate the position of the fetal presentation during birth, as it passes through the birth canal.
In total they are in number of four planes numbered from top to bottom, the foreground being the highest and the fourth the lowest. Needless to say, at the time of delivery, the vertical position and pelvic swing helps this pelvic descent.
Hodge's plans
- Hodge's foreground it is the superior of the four, it extends with an imaginary line that runs from the upper end of the pubic symphysis, in front, to the promontory of the sacral bone from behind. When the outgoing pole of the fetus reaches this plane, it is said that it is still mobile.
- Hodge's background it is an imaginary straight line parallel to the previous one and passes, from the front, from the lower edge of the pubic symphysis to the second or third vertebra of the sacral bone. When the outgoing pole of the fetus reaches this plane, it is said to be a fixed presentation.
- Hodge's third plane, also parallel to the first two planes, is a straight line that, at the height of the sciatic spines, cuts to the ischium and the fourth sacral vertebra. When the fetal presentation reaches this level it is said to be embedded. The most prominent part of the fetus protrudes from the vulva only between contractions.
- Hodge's flat room: line that starts from behind the vertex of the sacrum bone and extends parallel to all the anterior ones. It is said to be deeply embedded. The most prominent part of the fetus protrudes from the vulva even between contractions, and is the pre-birth step.
