how to create and concatenate dynamic variables in PHP?

In this php code, during a while loop, I was hoping to use later 3 variables called $menu_1, $menu_2, and $menu_3. Is this possible in PHP?

while($parent_row = mysql_fetch_array($parent_result)){    $menu_ = "";    $menu_ . $i = "\n\t$('#menu_" . $i . "').hover(function () {";}echo $menu_1;echo $menu_2;echo $menu_3;