How do the notochord and somites contribute to the developing vertebral column?

The notochord and somites are fundamental to the formation of the vertebral column.

The notochord serves as the initial longitudinal structural axis of the embryo, providing a scaffold around which the vertebrae develop. In higher vertebrates, it is a temporary structure that is eventually incorporated into the vertebral column as the central portion of the intervertebral discs, known as the nuclei pulposi.12

The somites are segmented blocks of mesoderm that form on either side of the notochord. Each somite differentiates into three parts: the dermatome, the myotome, and the sclerotome. The sclerotome is the critical component for the skeleton; its cells migrate to surround the notochord and the spinal cord. This sclerotomic tissue condenses to form the blastema, which serves as the precursor to the vertebral bodies (centra) and neural arches. This cartilaginous model is subsequently replaced by bone through the process of ossification.324