Tags: Anatomical Structure, Embryology.
In the developing vertebrate embryo the somitomeres (or somatomeres)are cells that are derived from the loose masses of paraxial mesoderm that are found alongside the developing neural tube. In human embryogenesis they appear towards the end of the third gestational week. The approximately 50 pairs of somitomeres in the human embryo begin developing in the cranial (head) region continuing in a caudal (tail) direction until the end of week four.