Why do joints have to be separated by an inch or so?

Question: Why do joints have to be separated by an inch or so?
- Keywords:
  joints,
  separation
Asked by bryan to Bernerd, Joseph, Ken on 14 Jul 2017.
- Joseph Olwendo answered on 14 Jul 2017:
  
  to allow for movement between the joints
- Bernerd Fulanda answered on 14 Jul 2017:
  
  Dear Bryan
  Lets say this, “we all need space”, so even the bones at the joints need space
  If the two bones were simply attached to each other, with nothing soft in between, the grinding of the two bones against each other as a result of movement would be extremely painful (you would cry if you try . Instead, all bones need a little space separating them from other bones. The space between bones is filled with a layer of connective tissue called cartilage which saves you this pain

Question: Why do joints have to be separated by an inch or so?