I've got a subspecies of human, Homo Volantes, that has been designed to live both in zero-G and in surface gravity. Several adaptations have been made, one of them including the replacement of fragile, normal human bones with artificial nanobots serving as their skeletal cells.
For the purposes of this question, here's the most relevant information about the skeleton.
- The materials of the skeleton are non-toxic to human cells
- The bones are effectively unbreakable and unmalleable
- While the H. Volantes is growing, individual cells can delete themselves to allow for the change in shape to occur
- The shape of the skeleton is the exact same as a human
The core of this question is essentially are there any vital functions of a skeleton that would be hindered by the skeleton being unmalleable and unbreakable?
Some mostly irrelevant information that might be useful if you need it.
- This subspecies is mostly human, with the only adaptations being an increased control over circulatory system pressure, and the metallic skeleton. Nothing else is changed.
- This subspecies spends their entire lives in large space stations in orbit around the Earth, however they occasionally spend time on the surface.
- Their metabolism has been modified to allow them to intake the materials required for the growth of the skeleton