The Timing, Format and Role of Anatomical Sciences in Medical Education

The Role and Value of Anatomy in the Medical School Curriculum

Many basic science and clinically oriented textbooks begin by addressing the anatomy of an organ, system or clinical area. Arguably, the reason the reader is introduced to the pertinent anatomy is that the structure of the body is fundamental to understanding all of the other basic and clinical medical sciences. The forerunners of today’s anatomists systematically studied the human body. And by doing so, anatomists provided a framework for the other basic sciences to investigate the way the various parts of the body normally function and what happens when body functions are impaired.

Most people are likely to equate anatomy with gross anatomy, i.e., the macroscopic structure of the body as revealed through the dissection of the body. However, anatomy encompasses four sub-disciplines collectively referred to as the anatomical sciences. Two of the sub-disciplines, histology and embryology, are also concerned with the structure and organization of the body, but histology examines the microscopic structures that cannot be seen by gross inspection and embryology deals with both the gross and microscopic growth and development of the body from conception to birth. The fourth major sub-discipline, neuroanatomy, is concerned with the gross anatomy, microscopic anatomy and embryology of the nervous system. Because of the complexity of this system, neuroanatomy focuses on the brain, spinal cord and the peripheral nervous system.

In preparing to be a physician, medical students must study the four anatomical sciences to become conversant with the origin, structure and organization of the body. As students of the human body, medical students learn the names that have been given to the structures and organs that comprise the body, how the body takes shape from the embryonic tissues that are formed after conception, and how the organs are built from the cells and major tissues of the body. In studying the anatomical sciences, students begin to learn the language of medicine that will allow them to communicate with patients and discuss patient problems with other healthcare professionals. Furthermore, the experience of dissecting the body and examining the microscopic structure of the body with a microscope helps students cultivate observational skills and learn the importance of attention to detail. The dissection of a cadaver helps students develop strengths in effective learning strategies, independent learning, and professionalism qualities early in their medical education.¹

Medical students readily grasp the relevance of gross anatomy to medicine. A course in gross anatomy and the experience of dissection is the vehicle that transforms naive onlookers into knowledgeable medical students and endows them with the recognition that they are part of the medical profession.² However, students are slower to recognize the importance of histology and embryology in their training despite the fact that impaired function primarily is realized through adverse effects on the development and microscopic organization of the cells that comprise the body. Students’ attitudes towards these topics develop early in their training and remain with them because medical students often do not see the impact that histology and embryology have on the practice of medicine.

In a traditional medical school curriculum, awareness and greater acceptance of the importance of histology and embryology only comes as medical students progress through the curriculum and are exposed to other basic science subjects such as physiology and pathology. Diminished expectations arise because it is difficult for students to appreciate the details of histology and embryology when the two subjects are not correlated with clinical problems, i.e., with the practice of medicine. The difficulty that students have with histology and embryology is exacerbated by their work with unfamiliar structures that are visualized only at the microscopic level.

Unlike gross anatomy, students may lose the macroscopic perspective during observation of the much smaller samples of comparable structures at the microscopic level. In embryology, the students’ task is complicated by having to visualize microscopic structures and understand the 3-dimensional changes that transform simple structures into complex shapes.

Another dilemma for students and instructors is that the entire knowledge base that medical students encounter is unlikely to be used by physicians after they enter the practice of medicine. The specific aspects of anatomy, histology, embryology or neuroanatomy that are used will most certainly depend on the physician’s role as a researcher, educator, or caregiver. However, basic concepts and practical aspects of the anatomical sciences undoubtedly will be used by most physicians on a daily basis. For example, in performing a physical examination, the structure and function of the human body is understood at its most macroscopic level and gross anatomy and neuroanatomy provide a basis for understanding the patient interaction at this level. Also, an understanding of the body in three dimensions is inherently necessary to interpret information from a variety of imaging techniques including radiographs, CT scans (Computerized Tomography) and MRIs (Magnetic Resonance Imaging). Furthermore, students must learn the normal microscopic structure of tissues and organs because organ function cannot be assessed through the outward appearance of an organ. An appreciation for how the smallest components of an organ are affected by pathogens, toxins, drugs, environmental hazards and other factors cannot be understood without being familiar with the normal morphology of the cells and tissues.

In the case of neuroanatomy, knowledge of the normal morphology of the nervous system provides students with an anatomical basis for localizing lesions and interpreting disorders that produce clinical symptoms. The ability to understand how focal damage to the nervous system results in specific symptoms displayed by patients depends upon specific structures that transmit information in the nervous system and their location relative to one another. Like gross anatomy, intimate knowledge of the structure of the nervous system provides future physicians with the knowledge needed to interpret imaging data and make a diagnosis.

With respect to embryology, the future physician is provided with an understanding of the structural changes that occur during the prenatal period and the processes that establish gender and the body as a whole. Knowledge of the normal developmental processes that result in a functional adult is needed for one to understand the reasons for errors that lead to malformations and congenital disorders.

When and How Should the Anatomical Sciences Be Incorporated into the Medical Education Curriculum?

Medicine is as much art as it is science and one of the central questions that medical school educators must confront is whether gross anatomy, histology, embryology and neuroanatomy should be taught as stand-alone courses or whether there should be an amalgamation of the anatomical sciences and the other basic science disciplines and clinical medicine.

The anatomical sciences typically have been presented early in the education of students, e.g., within the first year of medical school. The visual aspects of each of the anatomical sub-disciplines provides a more tangible introduction to the body before proceeding to other basic medical sciences or clinical subjects. This is true even in a non-traditional curriculum.

If gross anatomy and histology are presented as stand-alone courses, the students are more likely to develop a deeper understanding of these disciplines in themselves, including the themes and variations in structure that are seen at both the macroscopic and microscopic level. If gross anatomy and histology are presented concurrently, students will also, at some point, be able to relate the microscopic structure of the organs and tissues to what they observe in the gross anatomy laboratory. Embryology, however, should probably be presented in combination with gross anatomy at least for those aspects of development that result in gross anatomical malformations.

By scheduling gross anatomy, histology and embryology early in their training, students are provided with the morphological basis for understanding of the content of their other basic sciences classes. The timing also allows students to relate the normal microscopic anatomy to disease processes at the cellular level. Neuroanatomy is highly specialized and specific to the nervous system. In this case, the gross structure of the body and histology of the tissues provide students with the underpinnings needed for understanding the relationship of the nervous system to the other systems of the body. Thus, the timing of neuroanatomy in the curriculum is more variable and tends to occur later than the other anatomical sciences.

As an integrated course, gross anatomy can begin early with the components of a traditional course being distributed to a number of organ-based modules. However, the laboratory component of gross anatomy often dictates when gross anatomy is taught. Practical considerations that affect the position of gross anatomy in the curriculum include the use of the laboratory by other courses, cadaver preservation, and faculty availability.

The many different fields of basic medical knowledge including the anatomical sciences can be brought together in an effective manner by relegating the information to organ or system-based modules. With such an approach, there is more opportunity to distribute baseline anatomical information throughout several years of training. Using this approach, everything is not concentrated at the beginning of medical school or within a semester of work. The time frame is more gradual and as a result the students have an easier time learning and assimilating the material. Some academic programs even combine traditional and organ-based aspects of medical education by offering a traditional gross anatomy course that is followed by an organ-based curriculum.

The integration of material should include the different basic medical science disciplines and the presentation and analysis of related clinical applications. The approach has numerous advantages for the educational process. In particular, the amalgamation of the art and science of medicine can engage students in the material more quickly by its close association with a clinical setting, the amalgamation can influence the type and amount of material covered by the faculty, and the amalgamation of basic science and clinical medicine can show students how the information they are learning is applied to patient care and diagnosis.

It may be helpful to integrate some instruction in anatomical sciences into year 3 and 4 clerkships as well to reinforce the relationship between structure and disease processes that underlie clinical disorders.

In either a traditional or an organ-based curriculum, laboratories in the anatomical sciences offer an experience that is unique in the education of medical students. The laboratories provide the opportunity for a different kind of problem solving, e.g., locating structures and relating anatomical information to clinical disorders. The interactions with faculty in a laboratory setting are frequent and more casual, making it possible for students to develop closer relationships with faculty. Students often are required to present information in laboratory about dissections or problem solving sets to their peers providing an opportunity for the students to learn cooperatively in small groups. In comparison to the setting of a large lecture hall, the students also are more likely to discuss the subject material in the setting of a laboratory. The opportunity for interactions increases a student’s comfort level working as part of a team. It also helps develop communication skills, information sharing, and peer learning. Although the occurrence of laboratories associated with courses has decreased steadily, laboratories provide the opportunity to develop competencies that are essential in medical education.¹

Anatomy faculties are expected to do research and service as well as teach in courses that require significant amounts of time and resources. In reorganizing a curriculum, the tendency may be to eliminate laboratories or reduce the time set aside for laboratory in order to reduce contact time and reassign faculty resources. However, the laboratories complement didactic lectures and provide students with insights that can not be acquired in other ways. The dissection of a cadaver and reading microscope slides, for example, forces students to develop psychomotor skills, visualize in three dimensions, and deal with inherent variations that are commonly faced when examining actual specimens. In addition, the laboratories, which are interposed with lectures to reduce monotony, offer a different mode of learning that helps to reinforce the subject material.

Examples of Best Practices for Incorporating the Anatomical Sciences into the Medical Education Curriculum

Currently, each of the anatomical sub-disciplines is taught either as a stand-alone course or within an integrated organ or system-based module. A recent survey of courses in the United States3 indicates that 79% of the gross anatomy courses are offered as stand-alone courses compared with 29% that are offered in integrated modules. Regardless of the format, 100% of the gross anatomy courses have a laboratory associated with them and the vast majority use some combination of student dissection and prosection. Some gross anatomy courses also supplement dissection with computer-based tutorials that facilitate visualization of 3-dimensional structures.

A little more than half of all of the histology courses in the survey occur as stand-alone courses (51%). The remainder of all the histology courses surveyed (49%) are integrated into the curriculum with other subjects.³ The importance of microscopes and glass microscope slides in laboratory instruction is underscored by their use in all of the courses. A separate report supports this interpretation. In the survey of American and Canadian medical schools, 71.9 % of the respondents (histology course directors) specified that microscope and glass slides were being used in their courses.4 It is important to note in this regard that a survey of osteopathic physicians report that practicing physicians need microscope skills.⁵

A stand-alone histology course provides an intensity of study and continuity of information that develops familiarity with the information and skills that extend beyond the recognition of microscopic structures. On the other hand, the compartmentalization of the material is one of the strengths of the systems-based approach. Smaller units of material facilitate learning because the students are not overwhelmed by morphological differences observed in the other organs. The organ-based approach also integrates normal and pathological changes in structure more effectively. The lack of continuity and emersion in the subject however can lead to some students not fully developing the microscope skills that would be acquired in a traditional histology course.

Perhaps one of the most significant changes in instruction in histology to occur over the past 2 decades is the use of computers to display digitized microscope images. The technology provides numerous advantages including 1) the elimination of the skills necessary for the operation of the microscope, 2) the use of a common set of exemplary images that help students learn identifying features, 3) the ability to view images anytime and anywhere a computer is available, 4) the elimination of microscope slide collections, and 5) a more simplified method of storing specimens, i.e., digital images versus glass microscope slides.

One of the more recent advances in technology have resulted in the use of microscope and/or virtual slides. Virtual slides are exact digitized images of entire histological slides and although the means used to examine a virtual slide is different from that used to examine a microscope slide the similarity provides the students with a realistic interface that poses the same challenges as reading an actual microscope slide, i.e. students must still learn to analyze and interpret the image information.^6,7 Thus virtual slides provide an experience that is close to or identical to that performed in a traditional microscope laboratory without the need for learning how to operate a microscope.

The impact that digital images have had on the histology laboratory can be measured by number of schools that employ them.⁴ The gains in the use of computer technology are likely to lead to an enhancement of the materials used in the histology laboratory and greater flexibility in the way histological materials are accessed. If the latter is indeed the case, the debate over the use of computers in histology is more a matter of when and where the materials are acquired by students. However, even if the virtual slides can be viewed outside the confines of the school, students will continue to need curricular time set aside for formal laboratories that are staffed with instructors who can guide the students through the virtual materials, helping them to acquire the skills that are needed to analyze specimens, localize objects, and recognize structures. Access through the Internet could promote the development of web-based tutorials that could be made available to all schools.

For embryology, almost 80% of sampled programs have integrated embryology into modules. Most of the traditional embryology laboratories have been eliminated with only 7% of schools retaining laboratory sessions.³

Data from the American Association of Medical Colleges indicate that only 4 out of 109 medical schools in the United States and Canada list a course entitled Neuroanatomy.⁸ The vast majority of medical school courses go beyond the traditional method of studying the anatomy of the nervous system by providing an integrated approach that incorporates many disciplines.

Thus, gross anatomy and histology continue to be offered as stand alone course to a large extent, whereas embryology and neuroanatomy primarily have been integrated into organ-based modules.

REFERENCES

1. Böckers, A, Jerg-Bretzke, L, Lamp, C, Brinkmann, A, Traue, HC, Böckers, TM. 2010. The gross anatomy course: an analysis of its importance. Anat Sci Educ 3: 3-11.
2. Netterstrøm, I, Kayser, L. 2008. Learning to be a doctor while learning anatomy! 2008. Anat Sci Educ 1: 154-158.
3. Drake, RL, McBride, JM, Lachman, N, Pawlina, W. 2009. Medical education in the anatomical sciences: the winds of change continue to blow. Anat Sci Educ 2: 253-259.
4. Bloodgood, RA, Ogilvie, RW. 2006. Trends in histology laboratory teaching in United States medical schools. Anat Rec (New Anatomists) 289B: 169-175.
5. Pratt, RL. 2009. Are we throwing histology out with the microscope? A look at histology from the physician’s perspective. Anat Sci Educ 2: 205-209.
6. Dee, FR, Lehman, JM, Consoer, D, Leaven, T, Cohen, MB. 2003. Implementation of virtual microscope slides in the annual pathbiology of cancer workshop. Hum Pathol 34: 430.436.
7. Ogilvie, RW. 2007 Implementing Virtual Microscopy in Medical Education. http://www.iamse.org/development/2006/was_2006_s pring.htm Accessed on March 9, 2010.
8. American Association of Medical Colleges. http://services.aamc.org/currdir/section4/start.cfm Accessed March 15, 2010.