[Morphological study of the sacroiliac joint of aged Japanese and macroscopic and microscopic observations on its articular surface].

Little information has so far been obtained in anatomical investigation of the sacroiliac joint. The purpose of this study was to investigate the sacroiliac joints morphologically and pathologically for the purpose of revealing the cause of low back pain. The materials consisted of 24 cadavers with both sides of the sacroiliac joint present. Firstly, investigation was performed radiographically to determine the shape and slope of the joint at the anatomical position. Secondly, measurement of the articular surfaces on photographs was performed to show the average of various measurements e.g. area, circumference, length, width etc., further more the differences between sacral and iliac articular surfaces and that of sex were demonstrated. Next, macroscopic and microscopic investigations of the joint cartilage were were performed. In general, degenerative changes were seen in all specimens and marked changes were found on the middle-anterior part of the joint.