sciatic notch n either of two notches on the dorsal border of the hip bone on each side that when closed off by ligaments form the corresponding sciatic foramina:
a) a relatively large notch just above the ischial spine that is converted into the greater sciatic foramen by the sacrospinous ligament called also greater sciatic notch
b) a smaller notch just below the ischial spine that is converted to the lesser sciatic foramen by the sacrospinous ligament and the sacrotuberous ligament called also lesser sciatic notch
Medical dictionary. 2011.