The bone is present in almost every human embryo of 17–49 mm length, but then usually fuses with the ulnar side of the scaphoid.
[6] In most primates, including orangutans and gibbons, the os centrale is an independent bone that is attached to the scaphoid by strong ligaments.
[9] In chimpanzees, the bone fuses with the scaphoid first after birth, while in gibbons and orangutans this occurs first at older age.
[10] A good number of scholars have construed the scaphoid-centrale fusion as a functional adaptation to knuckle-walking,[11] since a fused morphology would better cope with the increased shear stress on this joint during this kind of quadrupedal locomotion.
An accessory navicular bone, also called os tibiale externum, occasionally develops in front of the ankle towards the inside of the foot.
