Cadaveric prosections are effective learning tools in anatomy education. They range from a fully dissected, sometimes plastinated, complete cadaver ("in situ" prosections), to a single, carefully dissected structure detached from a cadaver ("ex situ" prosections). While most research has focused on the advantages and disadvantages of dissection versus prosection, limited information is available on the instructional efficacy of different prosection types. This contribution explored potential differences between "in situ" and "ex situ" prosections regarding the ability of undergraduate students to identify anatomical structures. To determine if students were able to recognize the same anatomical structure on both "in situ" and "ex situ" prosections, or on either one individually, six structures were tagged on both prosection types as part of three course summative examinations. The majority of students (61%-68%) fell into one of the two categories: those that recognized or failed to recognize the same structure on both "in situ" and "ex situ" prosections. The percentage of students who recognized a selected structure on only one type of prosection was small (1.6%-31.6%), but skewed in favor of "ex situ" prosections (P[less than or equal to]0.01). These results suggest that overall students' identification ability was due to knowledge differences, not the spatial or contextual challenges posed by each type of prosection. They also suggest that the relative difficulty of either prosection type depends on the nature of the anatomical structure. Thus, one type of prosection might be more appropriate for teaching some structures, and therefore the use of both types is recommended.