Axial Skeleton

The term axial skeleton includes the skull, the vertebral column, the ribs and the sternum. These structures are distinct from the skeleton of the limbs.

Vertebral column, ribs and sternum

Blastema of the vertebral column

At S12, cells from the ventro-medial part of the somites (sclerotome portion of somite) are the first to migrate ventrally and medially to surround the notochord.