Greater sciatic notch muscles. Of these, the superior gluteal vessels and nerve pass out above the piriformis, and the other structures below it. The greater sciatic notch is wider in women (about 74.4 degree in female) than in men (about 50.4 degree in male). Greater sciatic notch The greater sciatic notch is a notch in the ilium, one of the bones that make up the human pelvis. It lies between the posterior inferior iliac spine (above), and the ischial spine (below). The sacrospinous ligament changes this notch into an opening, the greater sciatic foramen. The notch holds the piriformis, the superior gluteal vein
Aphanosauria "Marasuchus" (other avemetatarsalians) have their ischia only slightly contact at the middle portion of each bone. The tip of the ischium is also rounded and semi-triangular in cross-section, with the lateral (outer) face of each ischium thinning towards the lower edge of the bone while the medial (inner) face is flat and contacts the other ischium. Poposauroids and dinosaurs also have rounded ischia, but lack the semi-triangular shape, which is also known in "Asilisaurus". The ischium also has a groove on the upper part of the shaft. Unlike dinosaurs, aphanosaurs have an acetabulum (hip socket) which is closed up by