BRS Embryology, Fourth Edition is a succinct outline-format review for USMLE and course exams, with USMLE-style questions at the end of each chapter and a comprehensive USMLE-style examination at the end of the book. The book also includes radiographs, sonograms, computed tomography scans, and photographs of various congenital malformations. This updated edition has a new organization: prefertilization through the embryonic period; system by system; genetic abnormalities; and teratology. The chapter on structural chromosomal abnormalities has been substantially revised. This edition's review questions are in the clinical vignette-based format of the current USMLE. A companion Website offers the fully searchable online text and an interactive question bank.