The epaxial myobiasts give rise to a superficial and a deep muscle portion. The superficial muscle portion derived from the epimeres give rise to the long muscles of the back of the neck and trunk. These muscles serve as extensors of the vertebral column. The deep muscle portions derived from the epimeres gives rise to short intervertebral muscles.
The embryonic extensor muscles derived from the sacral and coc-cygeal epimeres degenerate and remain as the dorsal sacrococcygeal ligaments.