As sdcapmp described, it is common to lump the two together; however, what he said about Operations picking up where PM ends is inaccurate (or at the very least incomplete).
Instead, you should not view the two as a team that comes together with blurred lines. This can become blurry because Operations runs consistently and PM has defined beginning and ending. If there is a defined beginning and end you would think that it is difficult to get confused; however, that isn't the case.
Operations runs consistently, and policy and/or procedures enacted by the COO/Director of Operations can and will affect PM. That being said, best practices (as determined by PM) should be passed along to Operations for policy consideration or dissemination to others for use. This allows for continued growth in both areas, specifically with operational procedures and less reinvention of wheels from project to project.