If an incision is found on the inner face of the ilium, what can be determined about the type and size of the causative implement and the direction...

The ilium is the large, elephant ear shaped part of the pelvis.  It resembles two hemispheres of a valentine's day heart, split in two to make a left ilium and a right ilium.  In the ilia (plural), there is an indentation, a natural curvature to the structure of the body of the ilia.  This is the inner face of the ilia, so if an incision were made in this area, the implement used came in...

The ilium is the large, elephant ear shaped part of the pelvis.  It resembles two hemispheres of a valentine's day heart, split in two to make a left ilium and a right ilium.  In the ilia (plural), there is an indentation, a natural curvature to the structure of the body of the ilia.  This is the inner face of the ilia, so if an incision were made in this area, the implement used came in from the person's front.  The positioning of the ilium in regard to the body itself would indicate a thrust at a downward angle, probably around thirty degrees, or so.  As far as the type and size of the causative implement, that would depend on the size of the incision, the depth into the ilium it penetrated, and collateral damage to surrounding tissues, such as the muscles and skin.  A small, slim incision, with neat penetration of the surrounding tissues would indicate a smaller bladed implement, such as a surgeon's scalpel, while a larger, deeper, more jagged insertion would indicate an implement of heavier, rougher nature, like a hunting knife.