ischium http://upload.wikimedia.org/wikipedia/commons/2/29/Illu_pelvic_girdle.jpg ischial bone VSAO:0005006 MESH:A02.835.232.611.548 EMAPA:18727 galen:Ischium AAO:0000860 NCIT:C32884 os ischii FMA:16592 ischial MA:0001337 UMLS:C0022122 ischium bone this is_a hip bone in MA; in FMA it is a zone of bone organ. OpenCyc:Mx4rvlzMKpwpEbGdrcN5Y29ycA UBERON:0001274 GAID:208 uberon Paired bones of endochondral origin that constitute the posterior elements of the pelvic girdle. They are synostotically fused to each other and form the posterior part of the acetabulum.[AAO] Endochondral bone that is paired, forming the posterior part of the pelvis, articulating with the pubis and ilium. bone element endochondral bone pelvic girdle bone/zone ischial endochondral element lateral structure