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
Occipital bone Occipital bone The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cerebrum. At the base of skull in the occipital bone, there is a large oval opening called the foramen magnum, which allows the passage of the spinal cord. Like the other cranial bones, it is classed as a flat bone. Due to its many attachments and features, the occipital bone is described in