Canal sacral - Canalis sacralis
The sacral canal (vertebral canal) runs throughout the greater part of the bone; above, it is triangular in form; below, its posterior wall is incomplete, from the non-development of the laminæ and spinous processes. It lodges the sacral nerves, and its walls are perforated by the anterior and posterior sacral foramina through which these nerves pass out.
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
Anatomia geral > Ossos; sistema esquelético > Esqueleto axial > Coluna vertebral > Sacro [vértebras sacrais I - V] > Face dorsal > Canal sacral