Sacrospinous ligament Sacrospinous ligament The sacrospinous ligament (small or anterior sacrosciatic ligament) is a thin, triangular ligament in the human pelvis. The base of the ligament is attached to the outer edge of the sacrum and coccyx, and the tip of the ligament attaches to the spine of the ischium, a bone in the human pelvis. Its fibres are intermingled with the sacrotuberous ligament. The sacrotuberous ligament passes behind the sacrospinous ligament. In its entire length it covers the equally triangular coccygeus muscle, to which its closely connected. The presence of the ligament in the greater sciatic notch creates an opening (foramen),
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