Then the question is; when is the coccyx created in the foetus? And how are all organs and tissues of the foetus created from it? And when does it return back and settles down in the region of coccyx? To answer all these questions, let us follow the developments of human foetus and see how human being is created from it and how it resides in the region of tailbone and how it becomes the coccyx bone predicted by the Prophet (may the peace and the blessings of Allah be upon him), the single tiny bone that would be the base of recreation upon which the human body would be structured on the Day of Resurrection.
Moreover, Dr. `Usman Jilan explained this subject from medical point of view, then he summarized his explanation and said: After the creation and formation of embryo, the primitive node or the primitive steak returns back and settles down in the region of coccyx in its last vertebra while the remaining cell of the primitive steak or the primitive node in the coccyx region remains preserving its common characteristics and general abilities as if any element causes it to grown once again it grows like a puffy tumor resembling a deformed foetus producing some incomplete body parts like foot, hand, fingers and nails. The presence of these cells in the region of the coccyx records the beginnings of human body as well as it can stand as evidence for the truth of the Hadith which says that human body would be reconstructed from the coccyx on the Day of Resurrection. The region of the tailbone contains the cells of primitive node or the primitive steak which preserves the common abilities and general particularities as if it grows by any cause it grows as a single cell like the growth of a foetus forming the three primary layers (ectoderm and mesoderm and endoderm) just like the growth of a normal foetus developing it into a puffy tumor that resembles a deformed foetus producing some body parts like foot, hand, fingers and nails. The formed parts and systems remain inside the tumor as if the surgeon opens the tumor after eradication he finds the formed parts and systems in the tumor (like intestines, teeth, bones, hair, nerves and glands, etc.). This phenomenon bears clear evidence for the possibility of reconstruction of human body from the same coccyx on the Day of Resurrection that contains the cells of the primitive node or the primitive steak that preserves the common abilities and characteristics.
Furthermore, Dr. `Usman Jilan spoke about the characteristics of the primitive steak or primitive node which remains hidden in the tailbone, as he added: When the ovule is fecundated by sperm the foetus formation starts and the fecundated ovule is developed into a zygote, the zygote is divided several times going through many stages of divisions and growths until the foetus becomes an embryonic disk consisting of two dorsal layers; one of them is called Epiblast and the internal layer is called Hypoblast. Until the fourteenth day the foetus remains only a disk of two layers that have no sign of differentiation or characteristic. But the question is; what makes these non-distinctive and similar cells to form different body parts and body systems like digestive system, and nervous system etc.? And what directs them to organize the cells and to develop them into many and different types of cells, each one of them fulfil its particular duty producing after all the whole and complete human body?
The one who does the mission of forming and regulating all cells of the foetus is merely the primitive node or the primitive steak because before the formation of this steak there was no differentiation or determiner for the fate of the embryonic cells. There were only two layers in the back of the foetus but soon after the emergence of primitive node or primitive steak it begins to organize and form all organs and systems of the embryo, as the cells of the epiblast layer of the foetus move towards the primitive node where they are implanted and fixed also it becomes able to determine their fate and change their shapes and gives them instructions for the formation of primitive embryonic layers; mesoderm, ectoderm, endoderm, as well as it guides some of them to form nervous system through the primitive node. Some scientists and experts of embryology were interested in this phenomenon and conducted many experiments on it in order to find out the nature of this organization and formation. they carried out especial experiments on the primitive steak to discover the mechanism by which the primitive node organizes and forms the embryo from the primitive cells.