ischiopubic ramus ischiopubic ramus the ischiopubic ramus is a compound structure consisting of the following two structures: from the pubis, the inferior pubic ramus from the ischium, the inferior ramus of the ischium ischiopubic ramuspelvis. ischiopubic ramus is the region between "3" and "4c".right hip bone. external surface.detailsidentifierslatinramus ischiopubicusta98a02.5.01.007ta21313fma43533anatomical terms of bone it forms the inferior border of the obturator foramen and serves as part of the origin for the obturator internus and externus muscles. also, most adductors originate at the ischiopubic ramus. the fascia of colles is attached to its margin.