the photo shows a fragment of civilia as defined in ivor de wolf's "the italian townscape", a keyhole passage off the public sidewalk and the dead-end beyond.
the defining quality of a keyhole being the ceiling over of a passage-way between two parts of the street. in this example the public sidewalk, a part of the street, is connected to another part of the street, the private dead-end at the back of the building via the keyhole between them.
Posted with Blogsy