разводить руками {v. phr.}
razvodit' rukami
{literally} to part one's hands.
To demonstrate or experience the following feelings:
To be at a loss (do not know how to react);
Wonder at, to be surpised or be puzzled / perplexed.
Usually goes with hands down and being pulled apart.
"Когда он спросил врача, как он тут оказался, тот только развёл руками..." (К. Симонов). — "When he asked the doctor, how he found himself to be here, the man was at a loss (only pulled his hands apart)."
See also:
всплеснуть руками