Osmosis video - Development of the axial skeleton

The axial skeleton consists of the bones that run along the body's central axis - from the head to the tail, and it includes the skull, spine, and rib cage. The axial skeleton begins to develop very early in embryonic development, soon after gastrulation, meaning the period when the trilaminar disc with ectoderm, mesoderm, and endoderm layers is formed. Most axial skeleton bones develop from the mesoderm layer, except for the skull, which develops from the ectoderm.