Your Spine

Your spine is a quest item in the Fallout: New Vegas add-on Old World Blues.

Background
The Courier's spine is removed by the Sink Auto-Doc, together with the heart and brain on arrival in the Big MT.

Location
During the quest Old World Blues, the spine appears in The Sink and from this point on, can be returned at any time in the Courier's body (as well as removed again) with the same Auto-Doc.