Ischium jumping hurdles, basketball, and martial arts. These fractures occur at tubercles (bony projections that lack secondary ossification centers). Avulsion fractures occur where muscles are attached: anterior superior and inferior iliac spines, ischial tuberosities, and ischiopubic rami. A small part of bone with a piece of a tendon or ligament attached is avulsed (torn away). Ischial bursitis (also known as "weaver's bottom") is inflammation of the synovial bursa located between the gluteus maximus muscle and the ischial tuberosity, and is usually caused by prolonged sitting on a hard surface. Adoption of "ischium" into English-language medical literature dates back to c. 1640;
Squamous part of occipital bone eminence. The upper two fossae are triangular and lodge the occipital lobes of the cerebrum; the lower two are quadrilateral and accommodate the hemispheres of the cerebellum. At the point of intersection of the four divisions of the cruciform eminence is the internal occipital protuberance. From this protuberance the upper division of the cruciform eminence runs to the superior angle of the bone, and on one side of it (generally the right) is a deep groove, the sagittal sulcus, which lodges the hinder part of the superior sagittal sinus. To the margins of this sulcus the falx cerebri is attached.