ischial spine ischial spine the ischial spine is part of the posterior border of the body of the ischium bone of the pelvis. it is a thin and pointed triangular eminence, more or less elongated in different subjects. ischial spinecapsule of hip-joint (distended). posterior aspect. (spine of ischium labeled at upper left.)left hip-joint, opened by removing the floor of the acetabulum from within the pelvis. (spine of ischium labeled at center left.)detailsidentifierslatinspina ischiadicaspina ischiacaspina ischialista98a02.5.01.205ta21343fma17028anatomical terms of bone structure part attachment external surfacegemellus superior muscle internal surfacecoccygeus muscle, levator ani muscle, pelvic fascia pointed extremitysacrospinous ligament the pudendal nerve travels close to the ischial spine. clinical significance the ischial spine can serve as a landmark in pudendal anesthesia, as the pudendal nerve lies close to the ischial spine. additional images right hip bone, external surface, showing the greater and lesser sciatic notches, separated by the ischial spine articulations of pelvis. anterior view. pelvis. anterior view.