Sacrum sacrovertebral angle, an angle of 30 degrees from the horizontal plane that provides a useful marker for a sling implant procedure. The pelvic surface of the sacrum is concave from the top, and curved slightly from side to side. Its middle part is crossed by four transverse ridges, which correspond to the original planes of separation between the five sacral vertebrae. The body of the first segment is large and has the form of a lumbar vertebra; the bodies of the next bones get progressively smaller, are flattened from the back, and curved to shape themselves to the sacrum, being
Sacrum the direction of rotation of the superior portion of the sacrum opposite the side of the superior axis pole, and the last letter pertains to the pole. English "sacrum" was introduced as a technical term in anatomy in the mid-18th century, as a shortening of the Late Latin name "os sacrum" "sacred bone", itself a translation of Greek ἱερόν ὀστέον, the term found in the writings of Galen. Prior to the adoption of "sacrum", the bone was also called "holy bone" in English, paralleling German "heiliges Bein" or "Heiligenbein" (alongside "Kreuzbein") and Dutch "heiligbeen". The origin of Galen's term is