How they discovered it:

> The vessels were detected after Louveau developed a method to mount a mouse’s meninges – the membranes covering the brain – on a single slide so that they could be examined as a whole. “It was fairly easy, actually,” he said. “There was one trick: We fixed the meninges within the skullcap, so that the tissue is secured in its physiological condition, and then we dissected it."

Can someone explain what it means to fix the meninges to the skullcap? Do they mean they attached it to the skull bone? How then do they mount a curved bone to a slide?