As mentioned above, ventro-lateral growth from each half of the developing centrum produces costal process. Only in the thoracic region the costal processes form ribs. The costal processes of the cervical vertebrae remain short and form the anterolateral boundaries of the foramina tansver-saria of these vertebrae. In the lumbar region, the costal processes form part of the transverse processes of the lumbar vertebrae. In the sacral region, the costal processes fuse together to form the lateral mass of the sacrum.