Angular deformity of the spine

Spine deformity: The human spine develops faster during the embryonic period, and all structures are completed within a few weeks. After the spine is formed, it has its morphology and stability. The whole development process is divided into four phases. The first stage is called the chordal stage, which forms on the fifteenth day of the embryo, and the remaining part of it remains in the nucleus pulposus; the second stage is called the membranous stage, which starts from the 21st day to the end of three months; the third stage is cartilage. Period, from 5 to 6 weeks to before birth; the fourth period is the bony phase, which completes a part from two months to postnatal period. On the 14th to 21st days of embryonic development, a lamellar cell layer separates the amniotic cavity from the yolk sac. Since then divided into ectoderm, mesoderm and endoderm. The ectoderm forms a neural plate, the central depression of which becomes a neural sulcus, which then develops into a neural tube. The chordae are derived from mesenchymal cells, which are located deep in the neural tube, from the occipital to the tail. 42 pairs of somites are formed around the spinal cord along the midline. The mesoderm formed the original somite along the neural tube and gradually evolved into the "osteophyte", developed along the neural tube and the chordae, and finally formed the vertebral body.