Introduction: Clinical reasoning is a vital aspect of physician
competence. It has been the subject of academic research for
decades, and various models of clinical reasoning have been
proposed. The aim of the present study was to develop a theoretical
model of clinical reasoning.
Methods: To conduct our study, we applied the process of theory
synthesis in accordance with the Walker and Avant’s approach.
First, we considered clinical reasoning as a focal concept of our
study. Second, a search was carried out for the period 1984–
2018, using the PubMed, Google Scholar, PsycINFO, ERIC,
ScienceDirect and Web of Science databases to review the
literature to identify factors related to the clinical reasoning and
the nature of their relationships. Third, we organized clinical
reasoning into an integrated and efficient representation of the
Results: According to this study clinical reasoning is the iterative
process of intermediation between the recalled clinical knowledge
and the patient’s represented problem in the clinicians’ active
memory. We analogize the process of clinical reasoning to the
process of closure of a cognitive zipper. The recalled knowledge
in clinician’s memory resembles to one side of zippers teeth and
the evolving representation of the patient’s problem resembles
the other side of zippers teeth. So, the results of this study are
presented in three models:  multi-layer knowledge structure
model,  problem representation model and  cognitive zipper
model of diagnostic reasoning.
Conclusion: We propose a developmental model of clinical
reasoning. Several studies have tried to present models and
theories to clarify clinical reasoning, but it seems that these
theories and models could only explain part of this complex
process and not the whole process. Cognitive zipper model, due
to its developmental structure, can illustrate the clinical reasoning
process in more details than other models do.