Vintage real human medical skeleton wired ribs
A bit of an oddity. This must have been part of a full articulated skeleton that has become separated. It is a wired half rib cage with the ribs from the left side. The only missing one is the floating rib.
The ends of a couple of ribs have become broken over the years and it looks like they have had a coat of varnish, probably to help prevent them from becoming brittle.