Somitomere

Somitomere are loose collection of cells from paraxial mesoderm and early part of the embryonic development of vertebrates. They occur around the middle of the third week of pregnancy as paired Mesenchymsegmente right and left along the neural tube from the head ( cranial) starting downward ( caudal ). This results in a total of up to 50 segments depending upon the particular species. While trained from the first seven somitomeres among others, the extraocular muscles, facial and jaw muscles, formed from the remaining so-called somites, embryonic transition organs or somites, the ready hold the cell material for further development. From the 25th day about 3-4 somites are formed every day so by the end of the 5th week.

On the origin and existence of the Somitomere and its difference from somites, there are still controversial scientific discussions.