To carry out an ethnographic study on the work process in the sterilization unit of a hospital in Catalonia (Spain), we found the socially distributed cognition approaches of Hutchins and Kirsh useful. However, these approaches lack sufficient explanation on three important issues: (a) the pragmatic criteria for identifying and delimiting a relevant unit of analysis and therefore the setting and contexts of the work process; (b) the mechanisms and results of reciprocal influences between these levels of analysis; and (c) the relation between these levels. Therefore, we added several new elements to these approaches, in addition to Layder's model of contexts with some important modifications, with the aim of offering an interactive, cognitive and social proposal of analysis that clarifies these three issues, allowing a more exhaustive and broader empirical analysis that captures better the ‘social’ dimension embedded in the work processes.