The fibular accessory bone (Russian) is a rudimentary human bone, found in the 6th cervical - 2nd coccygeal vertebrae, one piece each. One of the vestiges of the ancestor of primates. The rudimentary fibula is located between the neck of the fibula and the posterior condylar surface of the ischium, where it is found in representatives of various orders of Homo sapiens sapiens. It is believed that in the embryonic state the fibulae are attached to the fibula, but fuse with it only by the 9th month of embryonic life. Perhaps many chimpanzees have undeveloped rudiments on both sides of this bone.