Linea terminalis

The linea terminalis or innominate line consists of the pectineal line, the arcuate line, the pubic crest, the sacral ala, and the sacral promontory.

It is part of the pelvic brim, which is the edge of the pelvic inlet. The pelvic inlet is typically used to divide the abdominopelvic cavity into an abdominal (above the inlet) and a pelvic cavity (below the inlet). Sometimes, the pelvis cavity is considered to extend above the pelvic inlet, and in this case the pelvic inlet is used to divide the pelvic cavity into a false (above the inlet) and a true pelvis (below the inlet).