DETERMINATION OF THE SACROILIAC ARTICU-LAR SURFACE WITH SPECIAL REFERENCE TO THE STRESS LOADING / 解剖学报

ABSTRACT

The diameters and projection area of the articular surfaces, contributed to the formation of the sacroiliac joint, were determined on 50 sets of pelvic bones with image analysing apparatus.By drawing a line connecting the most anterior point of the prominence to the deepest point of the posterior incisure, the articular surface may be divided into a superior and an inferior portions. The inferior portion was larger than the superior portion. Each portion of the articular surface on the ilium is slightly larger than that on the sacrum.In order to explore the relationship between the form of the articular surface and its function in transmitting the gravity of the human body, the stress of the neighbouring area near the anterior margin of the articular surface was determined. Moreover, the bony architecture on the cross section passing through the articular surface was observed. It suggests that the strain in the neighbouring area was in linear equation with the gravity loaded on the spinal column. The strongest stress was determined at the anterior margin of the anterior prominence and the thickness of the cortex lying on the relevant bones appears most obvious at the same sites. These results further improve that the bony architecture was consistent with the strain in bearing the body weight. Besides, the form of the articular surface was also adapted to its function.