1) Bone of the thorax 
In human anatomy, the presacral space is inside the pelvis, behind the rectum and in front of the coccyx and sacrum. Normally it is empty, or it contains a pocket of fat. It is usually covered by sigmoid colon. ==Clinical significance== The presacral space may contain one of several kinds of tumor. The most common tumor here is sacrococcygeal tera...
The retro- and extra- peritoneal soft-tissues that are anterior to the sacrum.
Type: Term Synonyms: retrorectal space