Prosection vs. dissection, the debate continues: Rebuttal to Granger

Abstract

Advances in science, medical diagnostics, and pedagogy have resulted in significant alterations in medical school curricula. Anatomy courses have reduced contact hours, reduced anatomical detail, and graying anatomy faculty members. Concurrently, there is a need to introduce clinical reasoning, physical examination skills, clinical imaging, and diagnostics much earlier in the curriculum than in years past. My learned colleague has presented thoroughly reasoned, articulate, and rational arguments for continuing the use of cadaver dissection in the teaching of anatomy to medical students. In this collegial debate, I will address individually the points advanced and question those that may not require the use of cadaver dissection. It is true that dissection facilitates learning of three-dimensional organization of gross anatomical structure. As outlined by Marks (2000), three-dimensional learning requires perception of pattern and form, and imagery, which itself requires time for reconstruction, testing, validation, and modifications of the image. In a dissection approach, however, pattern and form are not immediately apparent. Dissection begins with a complex structure and reduces it in the process of dissection. It has been argued that to facilitate learning of spatial relationships, one should start with visually simplified fundamental lines and symmetrical patterns and build up to the more complex organization (Miller, 2000). This could be best accomplished in the anatomy laboratory by studying carefully crafted prosections. Although it should not be the driving force behind curricular design, time in the anatomy laboratory is extremely valuable and must be used wisely. Based on student feedback and assessments, prosections are efficient learning tools (Alexander, 1970; Jones et al., 1978; Dinsmore et al., 1999; Leong, 1999). Although prosections are often used to demonstrate challenging dissections and provide alternative views, a recent study suggests that they may be better applied in replacement of simple, rather than complicated, dissections (McWhorter and Forester, 2004). Lastly, it behooves clinical anatomists to reflect on their own knowledge base, recognizing that although prosections seem like simplified anatomy to us, students may be equally challenged in learning anatomical nomenclature, structures, relationships, and concepts from prosected materials or through dissection. Several authors have spoken of the benefits of the multisensory learning environment of the dissection laboratory (Aziz et al., 2002) and cited particular structures that are best learned through dissection (Cahill et al., 2002). Few would argue that computerized haptic devices are quite at the stage of development to substitute for three-dimensional cadavers or prosections (Williams et al., 2004), although they are remarkable adjuncts to teaching. I suggest that one may obtain a multisensory experience and learn structures and relationships from an interactive exploration of carefully prepared prosected cadavers as well as from cadaver dissection. Students learning solely from dissection of embalmed cadavers may come away with distorted views of the biomechanical properties of tissues. Some structures, such as synovial sheaths, bursae, and joint cavities, are both altered by fixation and not well maintained due to desiccation during use. The physical properties of these structures, as well as those of fascial planes and fragile peripheral nerves, are more accurately represented in unpreserved cadavers than in embalmed cadavers. If unpreserved cadavers are not available, these structures may be appreciated in video demonstrations. It is true that the wide range of anatomically normal structural relationships may be made apparent in the anatomy laboratory. It is also true that few modern textbooks contain figures depicting normal variations, let alone the population frequency of each variation (Willan and Humpherson, 1999). Students working with prosections have the opportunity to view several variations, rather than the single variation that may be present in their dissection cadaver. Moreover, students moving rapidly through a dissection using a modern atlas may not recognize or preserve a variation. If the dissection is carried out in the process of developing a teaching prosection, the variation may be preserved for the education of many. Anatomy vocabulary, which is so necessary for communication in clinical medicine, may be learned through interactive use of prosections and many other learning materials, as well as through dissection. The act of dissection may facilitate the skilled use of instruments necessary for some clinical tasks (Moore, 1998; Newell, 1999; Ellis, 2001). Potentially overlooked, however, is the valuable opportunity to teach manual palpation skills on live humans (Ellis, 2001). Teaching surface anatomy in the anatomy laboratory allows for simultaneous verification of relationships in dissected or prosected cadavers. Self-directed learning, peer teaching, communication skills, and team-building can come from a prosection-based or dissection-based laboratory environment. Students working together to learn from prosected materials may spend more time focused on the learning objectives than students dissecting in a team with an entertaining colleague. As noted by numerous authors, the key is to make anatomy a quest for discovery. The inquiry-based approaches so eloquently described by Miller et al. (2002) could be used in prosection or dissection courses to make anatomy interesting and relevant. Much has been written about the cadaver as the medical student's first patient and first encounter with pathology and death and need not be expanded here. Anatomy education should continue in an integrated manner with other disciplines throughout the 4 years of medical education and beyond. Our charge, however, is not to produce clinical anatomists. Dissection may be fascinating and even consuming to us, but it is one component in the training of a multifaceted physician. We will mold better clinicians if we pique students' interest in anatomy. We should teach them to be lifelong learners, to apply a conceptual foundation to new problems, to identify, assess, and use resources, and to self-monitor judgment and clinical and communication skills. Student learning is not dependent on performance of a full dissection. It is instead dependent on outstanding instruction, engaged inquiry, interaction with peers, continual self-assessment, and dissemination and testing of one's newly acquired knowledge. Student learning is not dependent on performance of a full dissection. It is instead dependent on outstanding instruction, engaged inquiry, interaction with peers, continual self-assessment, and dissemination and testing of one's newly acquired knowledge. This article is dedicated to the memory of Dr. Hugh (Pat) Patterson, a devoted and innovative instructor and well-known proponent of prosection-based anatomical education at the University of California at San Francisco. This article is one of four invited papers that address the following question in a moderated debate format: “To what extent is dissection necessary in the learning of medical gross anatomy?” These articles were published in the November 2004 issue of The Anatomical Record Part B: The New Anatomist (Vol. 281B#1, pp 2–14). These articles can also be accessed online through our virtual issue on dissection and medical education (www.wiley.com/anatomy/dissection).