Ischium is a thick, rough-surfaced prominence below the lesser sciatic notch. This is the portion that supports weight while sitting (especially noticeable on a hard surface) and can be felt simply by sitting on the fingers. It serves as the origin for the inferior gemellus muscle and the hamstrings. The superior ramus is a partial origin for the internal obturator and the external obturator muscles. The inferior ramus serves partially as origin for part of the adductor magnus muscle and the gracilis muscle. The ischial ramus joins the inferior ramus of the pubis anteriorly and is the strongest of the hip
Aphanosauria bone, although perhaps a small portion was open according to a notch near where the ischium contacts the illium (upper blade of the hip). The gracile femur (thigh bone) of aphanosaurs possesses a characteristic set of features which can be used to diagnose the group. The proximal (near) surface of the bone, which connects to the hip socket, has a deep groove on it, rather than simply being a flat articulation surface. In addition, the bone's distal (far) articulation, which connects to the lower leg bones, is concave. The proximal part of the femur also has several bumps (tubers) on