Participation in clinical work is important for medical students' professional development. However, students often report that they experience a passive observer role, and further research on contextual factors that influence student participation is needed. The theory of practice architectures contributes a new perspective to this challenge by elucidating how cultural-discursive, material-economic, and social-political arrangements enable and constrain student participation in clinical work. The aim of this study was to explore how practice architectures in clinical learning environments enable and constrain medical students' participation. The study was designed as an ethnographic field study in three student clinics: 106 h of observation. Analysis comprised ethnographic analysis followed by application of the theory of practice architectures. The ethnographic analysis resulted in six themes: setting the scene, when to call for help, my room -- my patient, getting in a routine, I know something you don't, and my work is needed. Applying the theory of practice architectures showed that material-economic arrangements, such as control of the consultation room and essential artefacts, were crucial to student participation and position in the clinical workplace. Furthermore, co-production of a student mandate to independently perform certain parts of a consultation enabled a co-productive student position in the hierarchy of care-producers. The findings offer a conceptually generalisable model for the study of material and social dimensions of clinical learning environments. Although not all clinical learning environments may wish to or have the resources to implement a student clinic, the findings offer insights into general issues about the arrangements of student participation relevant to most clinical teaching contexts.