The authors propose reinvigorating and extending the traditional social history beyond its narrow range of risk behaviors to enable clinicians to address negative health outcomes imposed by social determinants of health. In this Perspective, they outline a novel, practical medical vulnerability assessment questionnaire that operationalizes for clinical practice the social science concept of "structural vulnerability." A structural vulnerability assessment tool designed to highlight the pathways through which specific local hierarchies and broader sets of power relationships exacerbate individual patients' health problems is presented to help clinicians identify patients likely to benefit from additional multidisciplinary health and social services. To illustrate how the tool could be implemented in time- and resource-limited settings (e.g., emergency department), the authors contrast two cases of structurally vulnerable patients with differing outcomes. Operationalizing structural vulnerability in clinical practice and introducing it in medical education can help health care practitioners think more clearly, critically, and practically about the ways social structures make people sick. Use of the assessment tool could promote "structural competency," a potential new medical education priority, to improve understanding of how social conditions and practical logistics undermine the capacities of patients to access health care, adhere to treatment, and modify lifestyles successfully. Adoption of a structural vulnerability framework in health care could also justify the mobilization of resources inside and outside clinical settings to improve a patient's immediate access to care and long-term health outcomes. Ultimately, the concept may orient health care providers toward policy leadership to reduce health disparities and foster health equity.