Advances in veterinary orthopaedics are assessed on their ability to improve the function and wellbeing of animal patients. And yet historically veterinarians have struggled to bridge the divide between an animal's physicality and its interior experience of its function in clinical settings. For much of the twentieth century, most practitioners were agnostic to the possibility of animal mentation and its implications for suffering. This attitude has changed as veterinarians adapted to technological innovations and the emergence of a clientele who claimed to understand and relate to the subjective experiences of their animals. While visualising technologies and human analogies have shaped the nuts and bolts of veterinary orthopaedic practices, an emerging awareness of the inability of radiographic images to apprehend or correlate to a patient's experience of their function reliably has required veterinarians to place a greater emphasis on the owner's knowledge of the "selves" inhabiting their animals. Rather than simply basing clinical judgments on the "look" of their patients, the indeterminacy in the connection between form and function has compelled veterinarians to put questions regarding particular human-animal relationships near the centre of their practices, not least in orthopaedic surgery. © 2009 Stazione Zoologica Anton Dohrn.