Why Prepare Your Pelvis? The pelvis plays a crucial role during childbirth. While many people think of the pelvis as a fixed boney structure, it consists of the two hip bones (the innominate bones), sacrum and tailbone. The pelvis also has joints; the pubic symphysis in the front of the pelvis and sacroiliac joints in the back. These allow the pelvis to be mobile. Ensuring the pelvis has mobility and that the supporting muscles have strength can potentially make the birthing process smoother. By