upper bar meaning in English

高杠
上柄

S knew only by the number of his cell , sprang up with an agility by no means to be expected in a person of his years , and , light and steady on his feet as a cat or a lizard , climbed from the table to the outstretched hands of dant s , and from them to his shoulders ; then , bending double , for the ceiling of the dungeon prevented him from holding himself erect , he managed to slip his head between the upper bars of the window , so as to be able to command a perfect view from top to bottom
唐太斯到目前为止只知道这个人的牢房号码，从他外表来看绝想不到他竟会这样敏捷，他一跳就跳了上来，象一只猫或一条蜥蜴那样敏捷的从桌子爬到唐太斯伸出的手上，又从手上爬到他的肩头上，然后，弯下腰，由于地牢的房顶使他无法伸直身子，所以他勉强把头从窗洞的栅栏间塞了出去，以便从上到下看个仔细。