Sacrum (Latin os sacrum) is a large triangular-shaped bone at the base of the spine, forms the upper rear portion of the pelvis, like a wedge located between two of the pelvic bones. The upper part of the rump is connected with the last lumbar vertebrae, lower - with the coccyx.

Sacral pain can be caused by:
- Pregnancy
- Sitting for long period
- Arthritis
- Pelvic inflammatory disease
- Endometriosis
- Tumor, infectious diseases and metabolic diseases.
- Uterune cancer
- Chronic prostatitis
- Prostate cancer
- Trauma
- Parametritis