The sacro-iliac joint : a clinical-anatomical, biomechanical and radiological study

This study is concerned with clinical-anatomical, biomechanical, and radiological properties of the sacro-iliac joints. It was initiated in order to acquire a better understanding of these 'enigmatic' joints. We started with researching the macroscopic anatomy of the auricular surfaces of the sacro-iliac joint. Macroscopic alterations of these surfaces have been described by several authors. Generally, such changes are considered to be pathological (Sashin, 1930; Bowen & Cassidy, 1981). If that were true, it could be expected that such changes would cause pain or sacro-iliac problems in (older) men since the changes become gradually more apparent from puberty onwards and are more prominent in men than in women. However, in the view presented in this study, macroscopic changes such as coarse texture and the appearance of ridges and grooves, reflect adaptations to stability, promoted by the increase in weight during the adolescent growth spurt. One reason for our view is the presence of coarse texture and ridges and . grooves in, practically. all male sacro-iliac joints (chapter 1). Another reason is the observation that the ridges and grooves in the sacro-iliac joint are complementary, and as a rule covered by intact cartilage, even in specimens of old age. All these features are more outspoken in men than in women. Differences between men and women may be attributed to child-bearing and to differential localization of the centre of gravity in relation to the sacroiliac joints (chapter I)