This paper examines the micro-processes of jurisdictional change in the eco-systems of healthcare work. This qualitative study investigated the expansion of geriatrician involvement in the perioperative pathway for older people. This study shows how, in response to opposition from surgeons and anaesthetists, geriatricians developed linked strategies that involved claiming the medical needs of surgical patients, and simultaneously integrating geriatric expertise into the non-surgical peripheries of the pathway. By progressively demonstrating their ability to mitigate risks and improve surgical outcomes, geriatricians acquired an expanded role in the care pathway. This paper develops the concepts of 'demonstrable claims' and 'jurisdictional clipping' to explain the strategies of jurisdictional expansion. It also problematises these strategies by suggesting that role expansion was controlled and contained by more powerful incumbent groups, whereby the expansion of work was limited to temporal and spatial peripheries that were less valued by surgeons or anaesthetists.