Greater sciatic notch 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 and artery, and the superior gluteal nerve; the inferior gluteal vein and artery and the inferior gluteal nerve; the sciatic and posterior femoral cutaneous nerves; the internal pudendal artery and veins, and the nerves to the internal obturator and quadratus femoris
Mastoid part of the temporal bone that portion of the tympanic cavity which is known as the attic or epitympanic recess. The tympanic antrum is a cavity of some considerable size at the time of birth; the mastoid air cells may be regarded as diverticula from the antrum, and begin to appear at or before birth; by the fifth year they are well-marked, but their development is not completed until toward puberty. The mastoid process is absent or rudimentary in the neonatal skull. It forms postnatally (starts to develop after 1 year old), as the sternocleidomastoid muscle develops and pulls on the bone. The term “mastoid”