CLEARING UP OF 21 SEGMENTS OF SACROCOCCYX DOWN FROM THE BACKBONE

Yang Liande

(Gansu College of TCM, Lanzhou)

It concludes, in the "chapter on the Measurement of Bone-Length in Ling Shu", an ancient Chinese medical book compiled in the Zhou Dynasty, that "there are 21 segments from the backbone to the sacrococcyx and they are measured one metre long". This conclusion has been used up to now. The equivalent of "one metre" in the Zhou Dynasty equal to 59.73 cm nowadays close to the average length from the first thoracic vertebra to the coccyx. In accordance with the segment number of thoracic and lumbar vertebrae, our predecessors had the point below the fifth lumbar vertebra spinous process exactly named Shiqizhuixue, that is called the 17th Vertebral Point. In fact, there are five segments of the sacral vertebrae and one segment of the coccyx. But the way by which our predecessors counted them is different from that of our modern doctors, so it is very important to study the structure of the sacrococcyx.

63 cases of the sacral morphology which we have observed show that, among them, 27 cases have 3 segments of tubercle of crista sacralis media each; 17 cases have 4 segments each; 10 cases have 2 segments each; 3 cases have 5 segments each; and in 3 cases, the tubercles are ossified into one line; in 2 cases, there is no crista sacralis media, because of the hiatus totalis sacralis; and one case has only one segment. The different position of the morphology of the hiatus sacralis is often related to the number and shape of the tubercle. The facies pelvina is comparatively identical. Each of 60 cases (95.2% of the 63 cases) has normally 5 segments and 4 pairs of sacral foramina. Only 3 cases are exceptional: in each of them, 6 segments and 5 pairs of sacral foramina have taken shape, because of the vertebrae spurae. So I think it was in accordance with the Baliaoxue which are often used in the theraputic practice that our predecessors drew the conclusion that the sacrococcyx had 4 segments.

According to the spinal column structure of the normal human body, I suggest that, in the limit table of the Bone-Length measurement, the measurement "21 vertebrae from the Dazhui down to the sacrococcyx" be changed into "23 vertebrae". The traditional location of point recorded in "the Chapter on Bone-Length Measurement in Ling Shu" will be introduced in footnotes.