Teaching Anatomy in the Digital World
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《新英格兰医药杂志》
Anatomy has a long and checkered past as a scientific discipline. In ancient Egypt, dissection was a religious ritual. During the Renaissance, it was considered an artistic and spiritual exploration of life, suffering, and death. Its heyday came in the 19th century, with the development of quick, effective surgical techniques on the battlefield and, later, the introduction of anesthesia, when knowledge of the structural intricacies of the body began to have practical significance for doctors. Throughout the 20th century, dissection of the human body served as an initiation rite for first-year medical students, even as the research focus in the field began shifting from gross anatomy to microscopical and ultrastructural anatomy.
(Figure)
Evolving Views of the Heart.
Panel A is an engraving by Karl Rokitansky (courtesy of the National Library of Medicine), Panel B a surface-rendered reconstruction from a multidetector computed tomographic scan (courtesy of Dr. Frank Rybicki, Brigham and Women's Hospital, Boston), and Panel C a tensor-diffusion magnetic resonance image showing fiber tracts in a dog's heart (courtesy of Dr. Leonid Zhukov, California Institute of Technology, Pasadena). (Videos of the beating heart appear in the Supplementary Appendix, available with the full text of this article at www.nejm.org.)
Today, the teaching of anatomy is at a crossroads. As an introduction to the language of medicine and an underpinning of the study of pathophysiology, anatomy remains an essential component of medical knowledge. But anatomy as a discipline is disappearing, and few new anatomists are being trained. This decline, in combination with an increased emphasis on early clinical experience and decreased time in medical school for basic science, is forcing a reexamination of the way in which anatomy is taught. A more focused approach has become essential, and traditional methods, based primarily on light microscopy and dissection, are being challenged.
There are obvious logistic problems with dissection. Storing cadavers is expensive, and issues such as preservation, reduced suitability for dissection due to illness or obesity, public perception,1,2 and a natural abhorrence on the part of some students are all potential barriers. Careful dissection is time-consuming, and it is increasingly difficult to fit it into the shrinking portion of the curriculum devoted to basic science. Light microscopes are expensive to maintain, and their effective use requires training and practice. It is difficult to obtain slides of consistently high quality for all students in a large class, and the cost of newer methods of preparation, such as immunohistochemical staining, is prohibitive.
It is simplistic, however, to propose eliminating light microscopy and dissection because they are time-consuming or unpleasant. Both have educational features that are particularly valuable for the teaching of anatomy. One vital function is their graphic demonstration of the wide variation in human structure, a concept that is difficult to capture in a textbook or atlas. Most students are astonished by the extent to which their specimen differs from the images in their atlas — a common source of confusion in early sessions in the dissection or histology laboratory. Any substitute for these methods would have to address this variability in a substantial way.
In performing dissection and light microscopy, students must spend considerable time searching for objects of interest. They learn subliminally about the surrounding tissues or structures while seeking a particular nerve, muscle, or cell, thus absorbing in passing the overall organization. The search is an important part of the learning experience and leads to more active engagement with the material. Repetition may also be key: after students have spent an hour locating and cleaning a muscle, moving it around to view it from all sides, they reach a three-dimensional understanding that cannot be replicated by an atlas.
Dissection may help students to work through their feelings about death and introduce them to their role as medical professionals. Nevertheless, it is hard to justify the retention of dissection on these grounds alone, since many others (social workers, psychologists, religious counselors) deal with death professionally without the benefit of dissection. Moreover, insofar as dissection has been perceived as an initiation rite that sets doctors apart from other caregivers, its use may be undesirable in a health care environment that emphasizes interdisciplinary teamwork.
As we explore new "virtual" methods of teaching anatomy, the educational challenges will be different for gross anatomy and microscopical anatomy, since the latter involves an essentially two-dimensional view. Virtual dissection is much more complex, requiring three dimensions and ideally including tactile information. In certain specialties such as radiology and surgery, virtual methods are unlikely to replace dissection in the near future. However, developments in computer capabilities and data processing offer the potential for more realistic and educationally valuable experiences than ever before.
With the advent of high-bandwidth data transmission and selective data delivery, it is possible to produce and transmit sets of digital microscopical images that are searchable and viewable at various magnifications. Students can focus on the information on the virtual slide, rather than the vagaries of microscope operation. With virtual histology, students may view several examples of each type of tissue and get some sense of the range that is considered normal. Sophisticated staining techniques may be included, since a single actual slide can produce virtual slides to be viewed by any number of students.
Digital animation has undergone a revolution in recent years. New programs permit the manipulation of realistic three-dimensional models with options for displaying complex textures, controlling the lighting, and "morphing" detailed shapes. Although the technology is currently quite expensive, it carries an exciting potential for the production of anatomical models that could be searched, manipulated, and explored by students.
Haptic (tactile) technology has also become more sophisticated. Realistic three-dimensional models are now used for training in endoscopic ultrasonography, chest-tube insertion, and laparoscopy. It is possible to develop realistic plastic models that could be peeled apart along natural fascial planes and simulate the color and feel of living tissue, offering tactile advantages over cadaveric specimens.
Until realistic holographic or three-dimensional visual and tactile simulations become a reality, dissection is probably still the best way to teach gross anatomy. But the pressures of time and curricular change may force us to reconsider how best to integrate dissection into medical training. If courses are structured according to a systems approach, the logistics of incorporating dissection over an extended period become particularly problematic. The solution may be to postpone dissection until a later point in training, when students can better grasp its value and can focus on their areas of interest.
Whenever they are taught, courses involving dissection should focus on clinically relevant structures, emphasizing surgical and procedural anatomy as well as surface and endoscopic anatomy. The review of radiologic studies should be stressed, since this is the way that anatomy is actually displayed in clinical practice. With routine sagittal and coronal reconstructions now available from multidetector computed tomographic scanners, a detailed three-dimensional understanding of structure is even more important than it used to be.
An anatomy laboratory, where prosections, models, selected specimens for dissection, Web-based teaching modules, and other high-technology resources would be available to learners at all levels, might be an even better use of resources. Students could come to the laboratory to review anatomy relevant to their current courses. Residents and fellows could review regions pertinent to their specialties. Physicians could earn continuing medical education credit for examining or dissecting material or practicing new techniques. Anatomy could thus play an expanded role at all levels of training and practice.
There are valid pedagogical reasons for the continued use of dissection and light microscopy despite logistic and psychological difficulties. Whatever the future holds, it is important not to change simply because change is possible. We must understand the virtues of these teaching methods in order to make the best use of them — and to select the most appropriate new methods to supplement or replace them.
Source Information
From Harvard Medical School, Boston.
References
Broder JM. In science's name, lucrative trade in body parts. New York Times. March 12, 2004:A1.
Zuger A. Anatomy lessons, a vanishing rite for young doctors. New York Times. March 23, 2004:F1.(Kitt Shaffer, M.D.)
(Figure)
Evolving Views of the Heart.
Panel A is an engraving by Karl Rokitansky (courtesy of the National Library of Medicine), Panel B a surface-rendered reconstruction from a multidetector computed tomographic scan (courtesy of Dr. Frank Rybicki, Brigham and Women's Hospital, Boston), and Panel C a tensor-diffusion magnetic resonance image showing fiber tracts in a dog's heart (courtesy of Dr. Leonid Zhukov, California Institute of Technology, Pasadena). (Videos of the beating heart appear in the Supplementary Appendix, available with the full text of this article at www.nejm.org.)
Today, the teaching of anatomy is at a crossroads. As an introduction to the language of medicine and an underpinning of the study of pathophysiology, anatomy remains an essential component of medical knowledge. But anatomy as a discipline is disappearing, and few new anatomists are being trained. This decline, in combination with an increased emphasis on early clinical experience and decreased time in medical school for basic science, is forcing a reexamination of the way in which anatomy is taught. A more focused approach has become essential, and traditional methods, based primarily on light microscopy and dissection, are being challenged.
There are obvious logistic problems with dissection. Storing cadavers is expensive, and issues such as preservation, reduced suitability for dissection due to illness or obesity, public perception,1,2 and a natural abhorrence on the part of some students are all potential barriers. Careful dissection is time-consuming, and it is increasingly difficult to fit it into the shrinking portion of the curriculum devoted to basic science. Light microscopes are expensive to maintain, and their effective use requires training and practice. It is difficult to obtain slides of consistently high quality for all students in a large class, and the cost of newer methods of preparation, such as immunohistochemical staining, is prohibitive.
It is simplistic, however, to propose eliminating light microscopy and dissection because they are time-consuming or unpleasant. Both have educational features that are particularly valuable for the teaching of anatomy. One vital function is their graphic demonstration of the wide variation in human structure, a concept that is difficult to capture in a textbook or atlas. Most students are astonished by the extent to which their specimen differs from the images in their atlas — a common source of confusion in early sessions in the dissection or histology laboratory. Any substitute for these methods would have to address this variability in a substantial way.
In performing dissection and light microscopy, students must spend considerable time searching for objects of interest. They learn subliminally about the surrounding tissues or structures while seeking a particular nerve, muscle, or cell, thus absorbing in passing the overall organization. The search is an important part of the learning experience and leads to more active engagement with the material. Repetition may also be key: after students have spent an hour locating and cleaning a muscle, moving it around to view it from all sides, they reach a three-dimensional understanding that cannot be replicated by an atlas.
Dissection may help students to work through their feelings about death and introduce them to their role as medical professionals. Nevertheless, it is hard to justify the retention of dissection on these grounds alone, since many others (social workers, psychologists, religious counselors) deal with death professionally without the benefit of dissection. Moreover, insofar as dissection has been perceived as an initiation rite that sets doctors apart from other caregivers, its use may be undesirable in a health care environment that emphasizes interdisciplinary teamwork.
As we explore new "virtual" methods of teaching anatomy, the educational challenges will be different for gross anatomy and microscopical anatomy, since the latter involves an essentially two-dimensional view. Virtual dissection is much more complex, requiring three dimensions and ideally including tactile information. In certain specialties such as radiology and surgery, virtual methods are unlikely to replace dissection in the near future. However, developments in computer capabilities and data processing offer the potential for more realistic and educationally valuable experiences than ever before.
With the advent of high-bandwidth data transmission and selective data delivery, it is possible to produce and transmit sets of digital microscopical images that are searchable and viewable at various magnifications. Students can focus on the information on the virtual slide, rather than the vagaries of microscope operation. With virtual histology, students may view several examples of each type of tissue and get some sense of the range that is considered normal. Sophisticated staining techniques may be included, since a single actual slide can produce virtual slides to be viewed by any number of students.
Digital animation has undergone a revolution in recent years. New programs permit the manipulation of realistic three-dimensional models with options for displaying complex textures, controlling the lighting, and "morphing" detailed shapes. Although the technology is currently quite expensive, it carries an exciting potential for the production of anatomical models that could be searched, manipulated, and explored by students.
Haptic (tactile) technology has also become more sophisticated. Realistic three-dimensional models are now used for training in endoscopic ultrasonography, chest-tube insertion, and laparoscopy. It is possible to develop realistic plastic models that could be peeled apart along natural fascial planes and simulate the color and feel of living tissue, offering tactile advantages over cadaveric specimens.
Until realistic holographic or three-dimensional visual and tactile simulations become a reality, dissection is probably still the best way to teach gross anatomy. But the pressures of time and curricular change may force us to reconsider how best to integrate dissection into medical training. If courses are structured according to a systems approach, the logistics of incorporating dissection over an extended period become particularly problematic. The solution may be to postpone dissection until a later point in training, when students can better grasp its value and can focus on their areas of interest.
Whenever they are taught, courses involving dissection should focus on clinically relevant structures, emphasizing surgical and procedural anatomy as well as surface and endoscopic anatomy. The review of radiologic studies should be stressed, since this is the way that anatomy is actually displayed in clinical practice. With routine sagittal and coronal reconstructions now available from multidetector computed tomographic scanners, a detailed three-dimensional understanding of structure is even more important than it used to be.
An anatomy laboratory, where prosections, models, selected specimens for dissection, Web-based teaching modules, and other high-technology resources would be available to learners at all levels, might be an even better use of resources. Students could come to the laboratory to review anatomy relevant to their current courses. Residents and fellows could review regions pertinent to their specialties. Physicians could earn continuing medical education credit for examining or dissecting material or practicing new techniques. Anatomy could thus play an expanded role at all levels of training and practice.
There are valid pedagogical reasons for the continued use of dissection and light microscopy despite logistic and psychological difficulties. Whatever the future holds, it is important not to change simply because change is possible. We must understand the virtues of these teaching methods in order to make the best use of them — and to select the most appropriate new methods to supplement or replace them.
Source Information
From Harvard Medical School, Boston.
References
Broder JM. In science's name, lucrative trade in body parts. New York Times. March 12, 2004:A1.
Zuger A. Anatomy lessons, a vanishing rite for young doctors. New York Times. March 23, 2004:F1.(Kitt Shaffer, M.D.)