These designations are arbitrary and were created by anatomists so that there is a language with which we can discuss anatomy. So, all terms are dependent on anatomical position, including flexion and extension. Both bring bones closer together, depending on the joints involved; so, "brings bones closer together" is a conditional definition and, as such, not a great one.
In general, questions about anatomy can be answered via Google and the many resources you'll find there, as this information is universal and not specific to our training. Pop your question into Google, and we suspect you'll find many wonderful resources that answer your question in various ways.
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