Chapter 1
An Overview of Developmental Events, Processes, and Abnormalities 1
The First and Second Weeks 2
The Embryonic Period The Early Embryonic Period 3
The Late Embryonic Period 4
The Fetal Period 5
Histological Concepts Samples of Epithelia and Connective Tissue 6
Skin and Embryonic Connective Tissue 7
Induction 8
Apoptosis 9
Segmentation and Early Pattern Formation Genetic Determination of Embryonic Axes and Segments 10
Segmentation and Segment Fates 11
Cell Adhesion and Cell Migration 12
Cell Differentiation and Cell Fates 13
Growth Factors 14
Classification of Abnormal Processes 15
Classification of Multiple Anomalies 16
Normal Versus Major Versus Minor Malformations 17
Marfan Syndrome 18
Apert and De Lange Syndromes 19
Examples of Deformations 20
Example of a Deformation Sequence 21
Drug-Induced Embryopathies 22
Terminology 23
Chapter 2
Early Embryonic Development and the Placenta 27
Adult Uterus, Ovaries, and Uterine Tubes 28
Ovary, Ova, and Follicle Development 29
The Menstrual Cycle and Pregnancy 30
The First Week:
Ovulation, Fertilization and Migration Down the Uterine Tube 31
Ectopic Pregnancy 32
Tubal Pregnancy 33
Interstitial, Abdominal, and Ovarian Pregnancy 34
The Second Week:
Implantation and Extraembryonic Membrane Formation 35
The Third Week: Gastrulation 36
Events Related to Gastrulation 37
The Fourth Week: Folding of the Gastrula 38
The Vertebrate Body Plan 39
Formation of the Placenta 40
The Endometrium and Fetal Membranes 41
Placental Structure Placental Structure 42
External Placental Structure; Maternal-Fetal Blood Barrier 43
Placental Variations 44
Placenta Previa 45
Summary of Ectodermal Derivatives 46
Summary of Endodermal Derivatives 47
Summary of Mesodermal Derivatives 48
Terminology 49
Chapter 3
The Nervous System 51
Formation of the Neural Plate 52
Neurulation 53
Neural Tube and Neural Crest 54
Neural Tube Defects Defects of the Spinal Cord and Vertebral Column 55
Defects of the Brain and Skull 56
Neuron Development 57
Development of the Cellular Sheath of Axons 58
Development of the Spinal Cord Layers 59
Development of the Spinal Cord 60
Peripheral Nervous System Development of the Peripheral Nervous System 61
Somatic Versus Splanchnic Nerves 62
Growth of the Spinal Cord and Vertebral Column 63
Embryonic Dermatomes 64
Adult Dermatomes 65
Development of the Brain Early Brain Development 66
Further Development of Forebrain, Midbrain, and Hindbrain 67
Development of Major Brain Structures 68
Growth of the Cerebral Hemispheres 69
Derivatives of the Forebrain, Midbrain, and Hindbrain 70
Cross Sections of the Midbrain and Hindbrain 71
Production of Cerebrospinal Fluid 72
Development of Motor Nuclei in the Brainstem 73
Segmentation of the Hindbrain 74
Development of the Forebrain Forebrain Wall and Ventricles 75
Relationship Between Telencephalon and Diencephalon 76
Development of the Pituitary Gland 77
Development of the Ventricles 78
Congenital Ventricular Defects 79
Terminology 80
Chapter 4
The Cardiovascular System 83
Early Vascular Systems 84
Vein Development Early Development of the Cardinal Systems 85
Transformation to the Postnatal Pattern 86
Vein Anomalies 87
Aortic Arch Arteries 88
Artery Anomalies Aortic Arch Anomalies 89
Anomalous Origins of the Pulmonary Arteries 90
Intersegmental Arteries and Coarctation of the Aorta 91
Summary of Embryonic Blood Vessel Derivatives 92
Formation of Blood Vessels 93
Formation of the Heart Tube Formation of the Left and Right Heart Tubes 94
Formation of a Single Heart Tube 95
Chambers of the Heart Tube 96
Bending of the Heart Tube 97
Partitioning the Heart Tube 98
Atrial Separation 99
Spiral (Aorticopulmonary) Septum 100
Completion of the Spiral (Aorticopulmonary) Septum 101
Ventricular Separation and Bulbus Cordis 102
Adult Derivatives of the Heart Tube Chambers 103
Fetal Circulation 104
Transition to Postnatal Circulation 105
Congenital Heart Defect Concepts 106
Ventricular Septal Defects 107
Atrial Septal Defects 108
Spiral Septum Defects 109
Patent Ductus Arteriosus 110
Terminology 111
Chapter 5
The Respiratory System 113
Early Primordia 114
Formation of the Pleural Cavities 115
The Relationship Between Lungs and Pleural Cavities 116
Visceral and Parietal Pleura 117
Development of the Diaphragm 118
Congenital Diaphragmatic Hernia 119
Airway Branching The Airway at 4 to 7 Weeks 120
The Airway at 7 to 10 Weeks 121
Development of Bronchioles and Alveoli 122
Bronchial Epithelium Maturation 123
Congenital Anomalies of the Lower Airway 124
Airway Branching Anomalies 125
Bronchopulmonary Sequestration 126
Palate Formation in the Upper Airway 127
The Newborn Upper Airway 128
Terminology 129
Chapter 6
The Gastrointestinal System and Abdominal Wall 131
Early Primordia 132
Formation of the Gut Tube and Mesenteries 133
Foregut, Midgut, and Hindgut 134
Abdominal Veins 135
Foregut and Midgut Rotations 136
Meckel’s Diverticulum 137
Lesser Peritoneal Sac 138
Introduction to the Retroperitoneal Concept 139
Midgut Loop 140
Abdominal Ligaments 141
Abdominal Foregut Organ Development 142
Development of Pancreatic Acini and Islets 143
Congenital Pancreatic Anomalies 144
Development of the Hindgut 145
Congenital Anomalies Duplication, Atresia, and Situs Inversus 146
Megacolon (Hirschsprung’s Disease) 147
Summary of Gut Organization 148
Development of the Abdominal Wall 149
Umbilical Hernia 150
The Inguinal Region 151
Anterior Testis Descent 152
The Adult Inguinal Region 153
Anomalies of the Processus Vaginalis 154
Terminology 155
Chapter 7
The Urogenital System 157
Early Primordia 158
Division of the Cloaca 159
Congenital Cloacal Anomalies 160
Pronephros, Mesonephros, and Metanephros 161
Development of the Metanephros 162
Ascent and Rotation of the Metanephric Kidneys 163
Kidney Rotation and Migration Anomalies Kidney Rotation Anomalies and Renal Fusion 164
Kidney Migration Anomalies and Blood Vessel Formation 165
Hypoplasia 166
Ureteric Bud Duplication 167
Ectopic Ureters 168
Bladder Anomalies 169
Allantois/Urachus Anomalies 170
Primordia of the Genital System 171
8-Week Undifferentiated (Indifferent) Stage 172
Anterior View of the Derivatives 173
Paramesonephric Duct Anomalies 174
Homologues of the External Genital Organs 175
Hypospadias and Epispadias 176
Gonadal Differentiation 177
Testis, Epididymis, and Ductus Deferens 178
Descent of Testis 179
Ova and Follicles 180
Summary of Urogenital Primordia and Derivatives 181
Summary of Genital Primordia and Derivatives 182
Terminology 183
Chapter 8
The Musculoskeletal System 185
Myotomes, Dermatomes, and Sclerotomes 186
Muscle and Vertebral Column Segmentation 187
Mesenchymal Primordia at 5 and 6 Weeks 188
Ossification of the Vertebral Column 189
Development of the Atlas, Axis, Ribs, and Sternum 190
Bone Cells and Bone Deposition 191
Histology of Bone 192
Membrane Bone and Skull Development 193
Bone Development in Mesenchyme 194
Osteon Formation 195
Compact Bone Development and Remodeling 196
Endochondral Ossification in a Long Bone 197
Epiphyseal Growth Plate Epiphyseal Growth Plate 198
Peripheral Cartilage Function in the Epiphysis 199
Structure and Function of the Growth Plate 200
Pathophysiology of the Growth Plate 201
Ossification in the Newborn Skeleton 202
Joint Development 203
Muscular System: Primordia 204
Segmentation and Division of Myotomes 205
Epimere, Hypomere, and Muscle Groups 206
Development and Organization of Limb Buds 207
Rotation of the Limbs 208
Limb Rotation and Dermatomes 209
Embryonic Plan of the Brachial Plexus 210
Divisions of the Lumbosacral Plexus 211
Developing Skeletal Muscles 212
Terminology 213
Chapter 9
Head and Neck 215
Ectoderm, Endoderm, and Mesoderm 216
Pharyngeal (Branchial) Arches 217
Ventral and Midsagittal Views 218
Fate of the Pharyngeal Pouches 219
Midsagittal View of the Pharynx 220
Fate of the Pharyngeal Grooves 221
Pharyngeal Groove and Pouch Anomalies 222
Pharyngeal Arch Nerves 223
Sensory Innervation Territories 224
Development of Pharyngeal Arch Muscles Early Development of Pharyngeal Arch Muscles 225
Later Development of Pharyngeal Arch Muscles 226
Pharyngeal Arch Cartilages 227
Ossification of the Skull 228
Premature Suture Closure 230
Cervical Ossification 231
Torticollis 232
Cervical Plexus 233
Orbit 234
Ear Development 235
Adult Ear Organization 236
Summary of Ear Development 237
Cranial Nerve Primordia 238
Cranial Nerve Neuron Components 239
Parasympathetic Innervation and Unique Nerves 240
Development of the Face Development of the Face: 3 to 4 Weeks 241
Development of the Face: 4 to 6 Weeks 242
Development of the Face: 6 to 10 Weeks 243
Palate Formation Palate Formation 244
Interior View of Palate Formation: Roof of Oral Cavity 245
Congenital Anomalies of the Oral Cavity 246
Floor of the Oral Cavity 247
Developmental Coronal Sections 248
Tooth Structure and Development 249
Dental Eruption 250
Terminology 251
Appendix A Summary of Common Congenital Anomalies Throughout the Body and Their Embryonic Causes 253
Index 257
