To remove a joint
The joint is deleted from your scene and the bone of the joint above the removed joint now connects to the joint below the removed joint.
If you removed a joint from the skeleton of a bound character, the character’s bind pose automatically adjusts and its skin history is retained.
To remove a parent joint and all its children
The bone between the current joint and its parent joint is removed.
The current joint and all its child joints are deleted from your scene.