Why does Oklahoma have an arm?

Excuse me, but I'm a bit perplexed by your question. Could you perhaps clarify your inquiry, as it seems to be a bit of a non-sequitur? Oklahoma, being a state in the United States, is a geographical entity and does not possess physical appendages such as arms. Perhaps you're alluding to a metaphorical or figurative arm, but without further context, it's difficult to provide a precise answer. Could you elaborate on what you mean by "Oklahoma having an arm"?