pubic symphysis, the slightly movable interpubic joint of the pelvis, consisting of two pubic bones separated by a disk of fibrocartilage and connected by two ligaments.Also called symphysis pubis.ymphysis mentaÂ´lis the line of fusion in the median plane of the mandible that marks the union of the two halves of the mandible. pubic symphysis (symphysis puÂ´bis) the line of union of the bodies of the pubic bones in the median plane.