September 5, 2006 Feature

Using Cadavers for Teaching Anatomy of the Speech and Hearing Mechanisms

see also

Although the study of anatomy through dissection remains a part of medical education, the future of anatomy education is beginning to change. Computer models, study modules, problem-based workshops, and computer-based tutorials are filling the classrooms at medical schools (Older, 2004). Although these are significant technologic and scientific advancements, the replacement of cadavers is a current topic of debate among medical schools throughout the world. In the United Kingdom, for example, the new system-based curriculum at many medical schools includes less than two hours of gross dissection per week-down from eight hours in the traditional core curriculum. Some schools have removed cadaver dissection entirely from the classroom (McLachlan et al., 2004).

A speech scientist specializing in anatomy likely would agree that dissection of the human body is indispensable for understanding the regions specific to speech. However, to what extent is anatomy education using a human cadaver necessary for students in communication sciences and disorders? Does exposure to a human cadaver produce better clinicians and researchers? Is an understanding of the underlying anatomy-for example, the size, shape, and relative orientation of the vocal folds and the surrounding muscles-important for ascribing treatment for an individual with a voice disorder? A study to evaluate what aspects of a curriculum create "good" clinicians would be presumptuous. However, as an old medical education philosophy (i.e., use of cadavers) is being challenged and in some institutions eliminated, several questions arise that should be evaluated within the field of communication sciences and disorders as these changes will spiral down to affect our classrooms.

History of Cadaver Dissection

Cadaver dissection has occupied a critical role in the history of medical sciences, including that of speech and hearing. Herophilus performed the first recorded dissection around 300 B.C. After that few were performed until the 17th and 18th centuries when theaters displayed cadaver dissections (Korf & Wicht, 2004). Artists such as Leonardo da Vinci and Michelangelo also performed dissection to enhance their artistic displays (Dyer & Thorndike, 2000).

Before dissection became legal in 1831, anatomy schools relied on grave robbers who sold bodies to schools and theaters, and bodies were illegally exported and sold to other countries. In 1831 the Massachusetts Anatomy Act was passed, allowing medical schools to receive corpses that remained unclaimed, thus moving the cadaver into the laboratory setting (Dyer & Thorndke, 2000).

Further legislation led to tighter controls and brought anatomy education into hospitals and universities. Body donation began to be publicly accepted, and cadavers were viewed as scientific resources.

In 1882, the Chicago College of Physicians and Surgeons opened and offered a three-year curriculum that included cadaver dissection. Because anatomic material was difficult to acquire, an organization (now known as the Anatomical Gift Association of Illinois) was founded in Chicago with the intent to legally embalm and distribute cadavers throughout the state, using deeds signed over by prospective donors. Deed-based programs now exist in all states except Wyoming, which uses services through Utah (National Anatomical Service). Today, the Anatomical Gift Association provides hundreds of cadavers each year for medical education and research.

The Department of Speech and Hearing Science at the University of Illinois in Urbana-Champaign relies on the deeded-bodies program for an undergraduate anatomy course. Overall, few universities in the country utilize such services in using cadavers to teach students. In addition, few programs have implemented the numerous computer and technologic advancements that the medical schools have created to enhance their students' learning experience. Instead of teaching through lecture and models, we should be finding innovative ways to present this complex three-dimensional anatomy to our students.

Anatomy Education in the CSD Curriculum

Anatomy is a part of the core curriculum in communication sciences and disorders. The field has been built on scientific knowledge gained through the study of the human body, particularly as it relates to the speech and hearing mechanisms. Research in cleft palate, for example, has been and continues to be based on histologic studies of human tissue, cadaver dissection, and in vivo examination such as use of conventional static and dynamic radiography, magnetic resonance imaging (MRI), nasoendoscopy, and computerized tomography (CT). All methods assume the researcher has a firm understanding of normal anatomy in order to ascribe abnormal anatomy.

The goals of anatomy education vary across departments; however, there are some commonalities. A first priority is an understanding of the skeletal framework and musculature specific to speech and hearing. This may include knowledge of shape, size, texture, function, and relative location of the anatomy. By understanding normal anatomy, students can begin to appreciate and conceptualize abnormal anatomy, which is often taught in subsequent classes. In addition visualization of anatomy in relation to the surrounding structures and muscles facilitates learning of the physiology related to the speech and hearing mechanisms. The ability to use the basic language of medicine related to our field is also an important skill that students should acquire while learning anatomy.

Methods for teaching anatomy in speech and hearing science departments vary across the country. A study reported in the ASHA Division 10, Perspectives on Higher Education newsletter (Adler, 2005), used a questionnaire to sample programs' use of tools for anatomy education. Of 161 questionnaires, 49% were returned. Results showed that the most common method for teaching anatomy and physiology in communication sciences and disorders departments is through lectures with models (98%) and videos (86%). A reported 17% of respondents used dissection in the laboratory class. However, it is unclear if dissection is of human or animal material. About a quarter (24%) of respondents reported using human specimens during their instruction.

The article does not give details, however, about whether whole cadavers are used. For example, specimens might include a human larynx in a jar that was obtained several years ago. This is in contrast to the use of whole-body human cadavers that are dissected and replaced each year. Using a whole body, or at least the intact torso, head, and neck, affords the student a better understanding of the relations and interactions among major systems and structures such as the larynx, respiratory mechanism, and upper airway in situ.

The late Willard R. Zemlin, a faculty member at the University of Illinois, was instrumental in building a strong foundation in anatomy science for communication sciences and disorders. As author of the well-known textbook Speech and Hearing Science: Anatomy and Physiology, Zemlin combined his efforts with the university's School of Basic Medical Sciences to bring dissection into the classroom for students studying communication sciences and disorders. He also took photographs and created drawings of the structures which are published in his book and are archived on a Web site that students use to study the structures related to speech (http://zemlin.shs.uiuc.edu/).

In the Department of Speech and Hearing at the University of Illinois, we have continued the tradition of using cadavers for anatomy education. We feel the benefits outweigh the increasing cost of cadavers and the time and cost involved in maintaining a cadaver laboratory. Undergraduate students (mostly juniors) attend one two-hour lab per week in which they study a whole-body cadaver that has been dissected outside of laboratory time by a teaching assistant. The cadaver is dissected in stages, beginning with the abdomen and working upward. Students do not see the process of dissection leading up to each stage of dissection, but they see the finished stage each week. After noticing this weakness of dissection outside of laboratory instruction time, we have implemented a computer-based technology that enables students to have a 3D experience in studying the anatomy and the process of dissection. Stereoscopic images consisting of two photographs taken to represent both the right eye and left eye are taken throughout the dissection. When both images are placed side by side and viewed with special viewing devices-which cost only about $2 each-a perception of depth is achieved.

At the beginning of the semester, the viewing devices are distributed and students are given instruction on how to use the Web site that displays the compiled images. These images can be viewed at www.shs.uiuc.edu/shs300/default.htm. This Web site allows students to study the cadaver outside of the laboratory including the sequence of dissection leading up to each stage of dissection presented during the lab session using their own personal computers.

By seeing a cadaver, students gain a better understanding of relative size of structures, thickness of muscles, orientation, and direction of muscles, and gain an appreciation of the layering of muscles. By using a whole-body cadaver, students learn the body as a system rather than as isolated and separate parts such as a preserved larynx in a jar. Also of importance is that the cadaver laboratory offers students a more memorable learning experience. Students in our department are very intrigued by the entire experience and learning is interactive, engaging, and exciting.

The main disadvantages of using cadavers are the cost of cadavers, which in Illinois is currently $1,450 each, and the cost and availability of laboratory space. Depending on the program's policies, these costs can be offset at least partly by assessing student lab fees. When such costs are not available, programs could consider sharing expenses and laboratory time with another department such as Kinesiology which focus primarily on the extremities.Programs could also encourage students to take an anatomy course in another department that offers a cadaver laboratory. The major drawback, however, is that such courses do not emphasize the primary structures and regions of the body of greatest importance to our students.

Some critics believe that the color, smell, and textures of cadavers are different from real life (McLachlan, 2004), but it is easy to argue that the use of cadavers is highly justified in relation to 2D pictures in textbooks and the unnatural texture of plastic models, some of which are anatomically inaccurate and can thus lead to wrong impressions of structural functions.

Anatomy Education's Future

Anatomy education with the use of cadavers likely always will attract public interest. The popular "Body Worlds" exhibits boast the phenomenal dissections and plastinations of Gunther Von Hagens (www.bodyworlds.com) and attract spectators of all ages. However, it is important that interest in cadaver dissection be sustained not only among the public, but in universities throughout the world. Removing cadavers from medical schools will cause a major shift in a time-honored tradition, which in turn will affect anatomy education in communication sciences and disorders.

Ideally, programs will use a didactic approach incorporating multiple modalities for learning in conjunction with lectures. This approach accommodates the variations in learning styles found among students. Using a cadaver to teach anatomy of the speech and hearing mechanisms also has several advantages. Changes in medical schools such as removing cadavers from laboratory may affect our curriculum as well by diminishing the importance placed on learning through dissection or navigation through the human body.

We would argue that a thorough understanding of the human anatomy through the accurate portrayal of speech and hearing structures should be enhanced by continuing or initiating the use of cadaver dissection, rather than diminished by the elimination of this valuable learning approach.

Jamie L. Perry, is a doctoral student in the Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign. She has been the cadaver laboratory instructor for two years, and was the instructor in the Anatomy and Physiology course last fall. Contact her at leverich@uiuc.edu.

David P. Kuehn, is a professor in the Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign. He has used cadavers in the teaching of anatomy of the speech mechanism for the last 25 years. Contact him at dkuehn@uiuc.edu.

cite as: Perry, J. L.  & Kuehn, D. P. (2006, September 05). Using Cadavers for Teaching Anatomy of the Speech and Hearing Mechanisms. The ASHA Leader.

References

Adler, R. (2005). Coursework in anatomy and physiology and neuroanatomy and physiology: what is current and where should we go? Perspectives on Issues in Higher Education, 8(1), 3-8.

Dyer, G. and Thorndike, M. (2000). Quidne mortui vivos docent? The evolving purpose of human dissection in medical education. Academic Medicine, 75(10), 969-979.

Korf, H. and Wicht, H. (2004). The public cadaver. Nature, 428, 805.

McLachlan, J., Bligh, J., Bradley, P., and Searle, J. (2004). Teaching anatomy without cadavers. Medical Education 38, 418-424.

Older, J. (2004). Anatomy: a must for teaching the next generation. Surgeon, 2(2), 79-90.

Persaud, T. (1997). A History of Anatomy: the Post-Vesalian Era. Springfield, IL: Charles C. Thomas.



  

Advertise With UsAdvertisement