Larsen’s Human Embryology (Schoenwolf,Larsen’s Human Embryology) 5th Edition

Book Preface

The fifth edition of Larsen’s Human Embryology, like the fourth edition, has been extensively revised. • The number of chapters has been expanded from eighteen to twenty. This was done to organize the material better and to incorporate new information efficiently and logically. • The text was heavily edited to increase clarity and avoid ambiguity, to improve accuracy, and to include many new scientific and medical advances since the last edition. • Building on the success of the section called “Clinical Tasters,” which was added in the fourth edition to introduce the clinical relevance of the material covered in each chapter, we added a new section—called “Embryology in Practice”—to close each chapter. The title of this section is a bit of a play on words; practice refers to both clinical practice and a chance for the reader to practice being a clinician and to use the material presented in the text to “walk through” a clinical scenario. As with the “Clinical Tasters,” the “Embryology in Practice” section focuses on the impact of birth defects on the lives of children and their families. Although fictitious scenarios, they reflect reallife stories encountered in clinical practice with real problems that patients and their families face. • Many new illustrations have been added; these additions reflect research advances and their clinical relevance. Many previous illustrations were thoroughly revised to facilitate student understanding. Although admittedly biased, we believe that the fifth edition of Larsen’s Human Embryology contains the best compilation in any one textbook of illustrations on human three-dimensional descriptive embryology, animal model experimental embryology, and human birth defects. • About fifty full-color animations have been linked directly to relevant sections of the text. These help the student understand not only the three-dimensional structure of human embryos, but also their fourdimensional structure as its complexity morphs and increases over time. • As with the fourth edition, new Content Experts have been chosen to partner with the authors in producing the fifth edition of Larsen’s Human Embryology. More than fifty new Content Experts are listed. With roughly the same number participating in the fourth edition, the textbook has now been critically evaluated by about 100 experts in their respective areas. Although that strengthens the book tremendously, it still does not make the book perfect, an impossible task in a complex and ever-changing field. Hence, we greatly appreciate input we receive for further improvement from students and faculty. Please continue to send your comments to [email protected].

Without students there would be no need for textbooks. Thus the authors thank the many bright young students with whom we have been fortunate enough to interact throughout our careers, as well as those students of the future, in eager anticipation of continuing fruitful and enjoyable interactions. For us as teachers, students have enriched our lives and have taught us at least as much as, if not more than, we have taught them. For this edition, we are especially grateful to the more than fifty Content Experts who were integral partners in the preparation of the fifth edition and who, like our students, also have taught us much. Each of the Content Experts read one or more chapters, offered numerous suggestions for revision, and in some cases even provided new text and illustrations. We have pondered their many suggestions for revision, but in the end, rightly or wrongly, we chose the particular direction to go.

The authors share a captivation for the embryo and have sought to understand it fully, but, of course, we have not yet accomplished this objective; thus our studies continue (we all are active researchers). Nevertheless, we took faith when writing this edition in a quote from one of the great scientific heroes, Viktor Hamburger: “Our real teacher has been and still is the embryo, who is, incidentally, the only teacher who is always right.” Finally, we must thank the many authors, colleagues, patients, and families of patients who provided figures for the textbook. Rather than acknowledging the source of each figure in its legend, we have clustered these acknowledgments into a Figure Credits section. This was done not to hide contributions but rather to focus the legends on what was most relevant.