The body schema is somehow the memory board of what we are. It does not lay in a well defined place in our body but it permeates the whole body. This is what allows us to define ourselves as we are.
We use the body schema as a reference : it allows us to maintain our identity throughout our live. We are always us throughout our live, despite the changes that time imposes on us.
We interpret everything that happens in our lives through our body schema. So if we are twisted in space and that it makes us suffer, the body schema permanently forces us into this twisting and this unbalance.
The body schema is the external sensor for the consistency, that is to say, it makes possible the personal interpretation of the environment and of oneself : so it is the personal reference.