THE SACROILIAC JOINT - ANATOMICAL STUDY IN THE CORONAL PLANE AND MR CORRELATION

The current clinical imaging technique applied to the sacroiliac joint (SLT) is coronal Computed Tomography (CT). The aims of this study wer e: 1) to section the cartilage, the ligaments of the SIJ, and their re lations to adjacent organs, in a coronal plane; 2) to correlate anatom ical and magnetic resonance (MR) sections; 3) to extend these data in vivo. A topographic dissection of a 52 year-old female specimen was pe rformed to identify the various components, and spatial relationships of the SIJ. Another fresh frozen 50 year-old female cadaver was chosen on CT criteria of normality, and examined with a high resolution (I-I R) T1-weighted spin echo sequence, in a plane parallel to the ventral limit of the first two sacral vertebrae. This cadaver was then sliced with a sliding gauge device (slice thickness: 5 mm, and device thickne ss: 1 mm). The SLT of a 28 year-old nulliparous volunteer, were examin ed in HR MR imaging, and with a faster sequence, for comparison with t he post mortem data. The slice study was correlated with conventional dissection. The continuity and thickness of the auricular cartilage, t he complex fascicles of proximal ventral and dorsal sacroiliac ligamen ts, and distant sacrotuberous and sacrospinous ligaments, were studied . In each plane, coronal HR MR imaging studies were correlated with an atomical sections. The clinical relevance of this comparison was to ex tend these data in vivo. The auricular cartilage and the ligaments of the SIJ are clearly analyzed by MR imaging, which could contribute to the study of sacroiliitis.