mouse TS23
  embryo
  cavities and their linings
  limb
  mesenchyme
  vertebral axis muscle system
  organ system
  skeleton
  axial skeleton
  cervical region
  lumbar region
  nucleus pulposus
  sacral region
  thoracic region
  cranium
  pectoral girdle and thoracic body wall
  pelvic girdle
  tail
  extraembryonic component