The Sacrum...The Holy Bone
There are two hundred and six bones in the human body, but we have but one bone that is holy: the sacrum.
The word "sacrum", meaning "sacred" in Latin, lives on in English anatomy as the name for the large heavy bone at the base of the spine.
The Romans called the bone the "os sacrum," which literally meant the "holy bone" and the Greeks termed it the "hieron osteon," the same thing, the "holy bone".
According to the Oxford English Dictionary, the anatomic "sacrum" entered English minus the "os" in 1753. The OED defines "sacrum" with precision (if not concision) as:
- "A composite, symmetrical, triangular bone which articulates laterally with the ilia, forming the dorsal (back) wall of the pelvis and resulting from the ankylosis (fusion) of two or more vertebrae between the lumbar and coccygeal regions of the spinal column."
The regions of human spine, lest we forget, are the cervical (neck) with 7 vertebrae, the thoracic (upper-back) with 12 vertebrae, the lumbar (lower-back) with 5 vertebrae, and the sacral region with 5 vertebrae.
The last sacral vertebra sits just above the coccyx, which during evolution was the beginning of the tail (and now, it seems, is mainly a bone to bruise or break).
The female sacrum is wider and straighter (less curved) than that of males. This difference in sacral anatomy has evolved because of its value to childbearing.
Why was the sacrum sacred? Several schools of thought exist about this matter, including the following:
- Temple: In Greek "hieron" meant not only sacred but also a "temple." It was the temple in the sense that within its bony concavity lay, in the female, the ovaries and uterus, the sacred organs of procreation.
- The afterlife: Thanks to its great size, the sacrum is usually the last bone of a buried body to rot. The ancients may thus have believed the sacrum to be the focal point around which the body could be reassembled in the afterlife.
- A sacrificial vessel: There is some archeological evidence to support the use of the sacrum as a vessel to hold the sacrifice in ancient sacred rites.
Whatever the exact explanation may be, the sacrum was surely sacred to the ancients. It was the holy bone, as its name reveals even today.
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Medically reviewed by John A. Daller, MD; American Board of Surgery with subspecialty certification in surgical critical care September 13, 2017