Bergman’s Comprehensive Encyclopedia of Human Anatomic Variation PDF
97.30 MB PDF
Preface
Since the beginning of time, differences between humans have made us identifiable to those around us. Some extreme forms of morphological variation have even resulted in individuals being either unique or outcasts. For example, dwarfs have been revered in various cultures and even represented in royal courts and some cultures have bestowed a god status on children born with multiple limbs. Other variations, however, have been viewed as “different” enough to warrant being ostracized. Children being born with a caudal appendage (tail) who were considered offspring of Satan exemplify this.
Human anatomic variation can be defined as human form that is outside of the normal. However, what is normal? This question is often very difficult to answer. For example, most would agree that having two breasts is normal but what about a woman with accessory breasts? Is this normal, abnormal or even pathologic? Is it a variant or an anomaly? Sometimes, the answer to these questions is based on cultural norms or societal acceptance.
Obviously, hair color is certainly varied among individuals with many having a color that doesn’t fit into the classic brown, black, red, or blonde categories. But are various hair colors that one of these terms does not apply to have a variation or is this simply an issue of definition e.g. red in the broader sense would include auburn, strawberry, etc.? In other words, our definition of normal is the gauge by which an anatomic trait is considered a variation or not. Some have tried to shed light on this by using such words as “borderlands.” Beyond the “border” a trait is thereby considered a variation. To confuse these issues, the term anomaly is and has been used interchangeably in regard to both variation and pathology. Herein, we have attempted to avoid pathologic anatomy but often, the line between an anatomic variation that is pathologic or predisposes one to pathology and one that is just a trait that is outside of what is considered normal is very gray. Moreover, as the term “anomaly” is often used to denote a variation that results in dysfunction or disease, we have tried to avoid this term when possible. However, the form of a structure may cause dysfunction in one person and not another. Therefore, “anomalies” do not always result in dysfunction or disease. The terms “abnormal” and “aberrant” have each been used loosely in the medical literature to describe anatomy that is non-pathologic or results in dysfunction.
Confoundedly, there are variations within variations. Where does one draw the line between a variation that is accepted as “normal” (the so-called normal variant) and a variation that is considered “abnormal”? In this text, we have attempted to be more inclusive than not. If the majority of individuals do not have an anatomic trait, then we have considered it a variation. With this however, the definition of majority has to be defined.
A quarter of a century ago, Dr. Ronald Bergman set forth to collect and publish a compendium of human variation. His textbook soon became the gold standard in human anatomic variation. As anatomists, we consulted this text almost daily. However, in the interim since its publication, radiologic technology and improved optics such as the surgical microscope have allowed us to see into the body with better accuracy than ever before. As a result, many more variations have come to the anatomist’s and clinician’s attention. Therefore, an updated textbook devoted to human anatomic variation seemed timely. However, as no single text on human anatomy can include all of the intricate details and structures of the body, so too can no single text on human anatomic variation capture all known or reported variants of the body, although we have tried. This tome will attempt to capture many of the known variants of the human form.
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