Abstract:

Objective　To obtain the angle of between the axis of the sacrospinous ligament and the human coronal plane in the human sagittal plane.　Methods　Eight fresh cadaveric specimen were disserted to find the insertion and the course of sacrospinous ligaments. 3D models were reconstructed from the pelvic CT scan data of 36 normal pelvis, the angle between the axis of the sacrospinous ligament and the human coronal plane in the human sagittal plane were calculated based on 3D coordinate of spatial points. 20 sacrospinous ligaments of 10 volunteers were conducted in the 3D MRI series and observed in the MPR(Multiple Planar Reconstruction) image. The MRI image findings of sacrospinous ligaments were compared among different views.　Results　The sacrospinous ligament passed from the sacrum to the ischial spine. A board range of insertion on the sacrococcygeal region were observed. We found in the CT data measurements that there was no significant differences between the left and the right sides in both genders (P>0.05). The differences between male and female were of no statistical significance (P>0.05). The mean angle of the 72 sides was (61.32±8.71)°. The mean angle measured on MRI data was （57.53±9.50）°. There was no statistical significant differences between the CT and MRI measurement results (P>0.05). We compared the MR imaging at the position of (60±5)° oblique coronal plane and the 3 normal planes and found that the ligaments can better be observed in oblique coronal plane (P<0.05).　Conclusions　The sacrospinous ligaments were well shown in (60.0±5)° oblique coronal plane.

Key words:  Pelvic, Sacroiliac joints, Sacrospinous ligaments, 3D Magnetic resonance imaging