Just like the four main directions (North, South, East and West) the body also possess four openings or doors- the East door is Mouth, the West door is Rectum, the North door is Head while the South door is Private part.
Four directions has the heaven, and also four the earth, (from these) the gods created the embryo. May they open her, that she shall bring forth!
Great as are the directions (of space) and the intermediate direction on either side, great as are the regions and the vistas of the sky; to these art thou superior, &c.