This book was prepared to present an integrated revi~w of selected topics in Human Embryology. It is designed specifically for students who have completed standard courses in the various anatomical disciplines and who wish to review the developmental history of the major organ systems. This book will provide medical students with a highly suitable review for Part I of the National Boards (NBME, Part I). R. E. Coalson ACKNOWLEDGMENTS I wish to acknowledge the invaluable assistance provided by my colleagues at the University of Oklahoma Health Sciences Center during the preparation of this review. I am grateful for the advice and patience of the Medical Editorial Department of Springer-Verlag, New York, Inc., and for the artistic talents of Mr. Shawn Schlinke, who prepared all of the illustrations. I particularly thank Dr. Randall B. Grubb, who proofread and prepared the manuscript in final form. TABLE OF CONTENTS GAMETOGENESIS . . . 1 FEMALE REPRODUCTIVE CYCLE . 7 FERTILIZATION AND PREGNANCY . . 10 IMPLANTATION AND FORMATION OF THE DECIDUAE . . . 13 FORMATION OF THE PLACENTA . . . 16 FETAL MEMBRANES AND UMBILICAL CORD . . 20 EARLY DEVELOPMENT OF THE CONCEPTUS . 23 DEVELOPMENT OF GENERAL BODY FORM · 28 NERVOUS SYSTEM . 31 MUSCULOSKELETAL SYSTEM . . . 41 INTEGUMENTARY SYSTEM .. . 50 ORAL CAVITY AND DEVELOPMENT OF THE BRANCHIAL APPARATUS . . 54 DIFFERENTIATION OF THE BRANCHIAL APPARATUS . 58

Gametogenesis.- Female Reproductive Cycle.- Fertilization and Pregnancy.- Implantation and Formation of the Deciduae.- Formation of the Placenta.- Fetal Membranes and Umbilical Cord.- Early Development of the Conceptus.- Development of General Body Form.- Nervous System.- Musculoskeletal System.- Integumentary System.- Oral Cavity and Development of the Branchial Apparatus.- Differentiation of the Branchial Apparatus.- Face and Palate.- Digestive System and Mesenteries.- Diaphragm and Body Cavities.- Respiratory System.- Urogenital System.- Cardiovascular System.- Fetal Circulation and Changes At Birth.