Arthur F. Dalley

From College to Clinic: Reasoning Over Memorization Is Key for Understanding Anatomy

Anatomy and physiology are taught in community colleges, liberal arts colleges, universities, and medical schools. The goals of the students vary, but educators in these diverse settings agree that success hinges on learning concepts rather than memorizing facts. In this article, educators from across the postsecondary educational spectrum expand on several points: (1) There is a problem with student perception that anatomy is endless memorization, whereas the ability to manage information and use reasoning to solve problems are ways that professionals work. This misperception causes students to approach the subject with the wrong attitude. (2) The process of learning to use information is as important as the concepts themselves. Using understanding to explain and make connections is a more useful long‐term lesson than is memorization. Anatomy should be presented and learned as a dynamic basis for problem solving and for application in the practice and delivery of quality health care. (3) Integration of form and function must be explicit and universal across all systems. (4) Using only models, images, audiovisuals, or computers cannot lead students to the requisite reasoning that comes from investigative dissection of real tissue. (5) Some undergraduate courses require students to memorize excessive musculoskeletal detail. (6) Learning tissue biology is a particular struggle for medical students who have no background from an undergraduate course. (7) Medical professors and students see benefits when students have taken undergraduate courses in anatomy, histology, and physiology. If medical schools suggest these electives to applicants, medical students might arrive better prepared and, thus, be able to learn clinical correlations more efficiently in the limited allocated time of medical school curricula. Anat Rec (New Anat) 269:69–80, 2002.

The collar plexus of subcutaneous thermoregulatory veins in the pigeon, Columba livia; its association with esophageal pulsation and gular flutter

SummaryHeat stressed pigeons dissipate heat by panting and gular flutter which is associated with upper esophageal pulsation; these activities depend on evaporative cooling and convection from mucosal surfaces. The collar plexus, an unusual subcutaneous system of erectile veins, is the specialized vascular apparatus that seems to serve as the heat exchanger for gular flutter and upper esophageal pulsation. The collar plexus lies between the dermis and a deeper muscle sheet, extending from the head to the thoracic inlet in mature pigeons. The slightly filled plexus is inconspicuous, resembling an ordinary venous bed, and consists of thick-walled veins having small lumina, similar to arteries. When moderately-filled, the veins of the plexus distend and abruptly transform into “beaded” veins with contorted, sacculated expansions separated by constricted segments.During heat stress, engorgement of the plexus occurs rapidly by continual flow over arteriovenous anastomoses that empty arterial blood directly into the beaded veins. Constriction of veins draining the plexus impedes venous return to the jugular veins, thereby maintaining tumescence of the plexus. Disgorgement of the plexus also occurs abruptly. Intimate contact between the deep aspect of the engorged plexus and the trachea and upper esophagus provides for heat transfer from the plexus to the mucosal surfaces of these structures where evaporative cooling takes place. During esophageal pulsation the esophageal surface extends and augments the respiratory dead-space area used for evaporative cooling. Thus a possible advantage of cooling by upper esophageal pulsation is that, like gular flutter of the oropharynx, it may minimize the amount of air that must pass over gas exchange surfaces, thereby limiting the washout of CO2 and consequent acid-base disturbances that occur during panting in extreme heat stress.Ability to inflate the esophagus is of general occurrence among the pigeons and doves (Family Columbidae). The collar plexus is also widespread, having been found in representatives of five of the examined six main subdivisions of the Columbidae.

THE AMERICAN ASSOCIATION OF CLINICAL ANATOMISTS (AACA) : THE OTHER AMERICAN ANATOMY ASSOCIATION

WHAT IS THE PURPOSE OF THE AACA? The American Association of Clinical Anatomists (AACA) strives to advance the science and art of clinical anatomy. Through its meetings, journal, and activities, it encourages research and publication in the field and maintaining high standards in the teaching of anatomy. Historically, the association was founded (in 1983) by a group of clinicians and basic scientists concerned about a declining role and appreciation of gross anatomy in medical education and clinical training. The scope and purpose of the association has since grown to embrace anatomy in all its aspects—gross, histologic, developmental, and neurologic—as applied to clinical practice, focusing on the application of anatomic principles to the solution of clinical problems, and/or the application of clinical observations to expand anatomic knowledge.

Other thoughts on human variation

I am a long-standing fan of the work of Ronald Bergman, Adel Afifi, and colleagues, and wish to join the queue of admirers expressing appreciation for their important, scholarly work. As a gross anatomist and textbook and atlas author/editor, I have made much use of the bound editions (indeed, had to purchase a second copy of the Compendium [Bergman et al., 1988] after my frequently-borrowed initial copy finally failed to be returned), and more recently, the newer online version. The internet is truly the right place for this important data base. Not wishing to tarnish the accolades, however, I must take exception with some of Dr. Bergman’s statements and implications expressed in his Thoughts on Human Variations article (Bergman, 2011). He seems to lose his keen sense for variation as he paints with a very broad brush, vilifying anatomical textbooks, national cross-sectional data bases, and those employing sound, tried-and-true methods of didacticism. Contemporary anatomy textbooks and atlases themselves demonstrate a large degree of variation, ranging from short core outlines to comprehensive tomes, from purely structural to highly functional and clinically-applied in terms of content. This is a reflection of both author intent and the demands of the marketplace. However, essentially all support dissection experience as being vital to true understanding of anatomical structure and relationships. One of the primary and most frequent reasons cited to justifying cadaver dissection is developing an awareness of human variation (Gray et al., 1974; Skandalakis et al., 1974; Beahrs, 1991; Amadio, 1996; Willan and Humpherson, 1999; Wise, 2000; Ellis, 2001; Aziz 2002; Hasan, 2011), and essentially all anatomical textbooks address this important anatomical phenomenon from the outset in their Preface or Introductory chapter. Understandably, the short texts will spend less time addressing specific variations while longer texts are likely to include more detail. An awareness of specific variations is not nearly as important as an awareness of the near constant presence of variation, some perception of the degree of variations that may occur within the range of ‘‘normal,’’ or that the ‘‘typical’’ variety (the most common variation) may occur considerably less than half the time. I have learned that the most skilled surgeons do not necessarily have an awareness of the likelihood of encountering a specific variation, but rather a perception of the most likely anatomy to be encountered while assuming that each case is going to be atypical in some aspect, i.e. the variation that matters most is the case under study. Dr. Bergman does not seem to hold in high regard the relatively recent and quite miraculous achievements of cross-sectional data bases, such as the NLM’s Visible Human Project because of their small n value. It is true that some have misinterpreted or overestimated certain aspects of their purpose (medical school administrators are among the most at fault in this regard; they have been proclaiming the demise of the cadaver’s utility in the face of technology for decades). However, these projects and their derivatives—never represented as anatomical standards by their producers—have revealed much about the body’s planar and three-dimensional anatomy, both typical and atypical. One of the first questions my students ask when they learn about these data bases is ‘‘What variations were revealed?’’ And while it is true that the large expenses involved keep the numbers low, the Visible Human Project’s n-value has now tripled (four specimens was the original goal), and several other nations have made significant contribution in this regard through parallel projects (Robb and Hanson, 2006). Dr. Bergman seems to imply that there is no ‘‘typical’’ or normal anatomy that should be taught. I agree that understanding the concepts underlying somatic plexuses is more important than memorizing a rigid pattern, especially if variations such as preand postfixed plexuses are never introduced. To learn to solve problems involving plexuses, however, an agreed upon working model becomes important. It is a longstanding principle of education—whether teaching the fundamentals of the alphabet in primary education, or the functional anatomy of the autonomic nervous system in medical school—that first you establish a baseline or a basic model, and afterward explain the variations, fine details, and exceptions to the rules. If you introduce all the shades of gray from the outset, development of working models (understanding) is slow to evolve, and more likely to be faulty or erroneous. Further, if assessment reflects presentation, as we are told it should, the answer to every examination question becomes ‘‘sometimes’’ or ‘‘maybe.’’ Problem solving, which is appropriately taking center stage over memorization of fact, requires working models that enable interpretation, and provide a baseline from which variation can be described, understood, and appreciated.