Etiology-Based Dental and Craniofacial Diagnostics

By Inger Kjaer

Etiology-Based Dental and Craniofacial Diagnostics explores the role of embryology and fetal pathology in the assessment, diagnosis, and subsequent treatment planning of a wide range of disorders in the dentition and craniofacial region. Initial chapters cover various aspects of normal dental and craniofacial development, providing the necessary biological background for understanding abnormal patient cases. Chapters then focus on the etiology behind a wide range of cases observed in everyday practice—including deviations in tooth morphology and number, tooth eruption, root and crown resorption, and craniofacial malformations, disruptions and dysplasia. 

• Unique new work from a leading authority in orthodontics, craniofacial embryology and fetal pathology
• Demonstrates how human prenatal development offers unique insights into postnatal diagnosis and treatment
• Clinical significance and implications are highlighted in summaries at the end of each chapter
• Ideal for postgraduate students in orthodontics, paediatric dentistry and oral medicine

• Language: English
• Publisher: Wiley
• Release date: Aug 22, 2016
• ISBN: 9781118912102

Book preview

Contents

Cover

Title Page

Copyright

Dedication

Preface

Introduction

Limited Access to Human Material

Content and Structure of the Book

Acknowledgments

Chapter 1: Craniofacial Development and the Body Axis: Normal and Pathological Aspects From Early Prenatal to Postnatal Life

Body Axis Pre- and Postnatally

Craniofacial Development Pre- and Postnatally

Craniofacial Morphology and Growth

Highlights and Clinical Relevance

Further Reading

Chapter 2: Craniofacial Development and the Brain: Normal and Pathological Aspects from Early Prenatal to Postnatal Life

Central Nervous System in Relation to Neurocranial Development Pre- and Postnatally

Peripheral Nervous System Pre- and Postnatally

Highlights and Clinical Relevance

Further Reading

Chapter 3: Developmental Fields in the Cranium and Alveolar Process

Definition of Developmental Field

Developmental Fields in the Cranium

How can Craniofacial Fields be Proven?

Developmental Fields in the Alveolar Process

Highlights and Clinical Relevance

Further Reading

Chapter 4: Tooth Development and Tooth Maturation from Early Prenatal to Postnatal Life

Histological Evaluation of Early Tooth Development

Radiographic Evaluation of Normal Dental Maturation

Clinical Evaluation of Dental Maturity

Tooth Formation from the Initial Stages to the Eruption Stages: Relation to Fields, Gender, Age, and Skeletal Maturity

Similarities and Differences in Primary and Permanent Dental Development

Highlights and Clinical Relevance

Further Reading

Chapter 5: Periodontal Membrane and Peri-Root Sheet

Periodontal Membrane

Peri-Root Sheet

The Peri-Root Sheet in the Primary and Permanent Dentition

Highlights and Clinical Relevance

Further Reading

Chapter 6: Normal Tooth Eruption and Alveolar Bone Formation

Tooth Eruption Mechanism and Alveolar Bone Formation

Tooth Eruption and Jaw Growth

Eruption Sequences in the Primary and Permanent Dentition

Highlights and Clinical Relevance

Further Reading

Chapter 7: Etiology-Based Diagnostics: Methods and Classification of Abnormal Development

Why Use Etiology-Based Diagnostics?

Definitions of Key Words

Analyzing the Dentition, Oral Cavity, and Cranium: Practical Guide

Diagrams for Diagnostics

Highlights and Clinical Relevance

Further Reading

Chapter 8: Deviation in Tooth Morphology and Color: Normal and Pathological Variations Including Syndromes

Primary Dentition: Crown, Root, and Pulp

Permanent Dentition: Crown, Root, and Pulp

Abnormal Dental Development: Fields and Bilateralism

How to Analyze the Etiology Behind Deviation in Tooth Morphology: is it Malformation, Disruption Or Dysplasia?

Highlights and Clinical Relevance

Further Reading

Chapter 9: Deviations in Tooth Number: Normal and Pathological Variations Including Syndromes

Agenesis: Possible Etiologies

Agenesis of the Primary and Permanent Dentition: Hypodontia

Supernumerary Teeth: Possible Etiologies

Supernumerary Teeth in the Primary and Permanent Dentition: Hyperdontia

How to Analyze the Etiology Behind Deviation in Tooth Number

Highlights and Clinical Relevance

Further Reading

Chapter 10: Tooth Eruption and Alveolar Bone Formation: Abnormal Patterns Including Syndromes

Pathological Eruption of Primary Teeth

Pathological Eruption of Permanent Teeth

Abnormal Eruption in Syndromes and Dysplasia

Segmental Odontomaxillary/Mandibular Dysplasia

Eruption and Heredity

Eruption Problems in Both Dentitions

Localized Abnormal Alveolar Bone Formation

Why Analyze the Etiology Behind Abnormal Eruption?

Highlights and Clinical Relevance

Further Reading

Chapter 11: Root and Crown Resorption: Normal and Abnormal Pattern Including Syndromes

Tooth Resorption Theory

Resorption in the Primary Dentition

Resorption in the Permanent Dentition

Other Examples of Resorption

Conclusion

How to Analyze the Etiology Behind Abnormal Root Resorption in the Permanent Dentition

Highlights and Clinical Relevance

Further Reading

Chapter 12: Apparently Normal Nonsyndromic Dentitions are Phenotypically Different: The Interrelationship between Deviations in the Dentition and Craniofacial Profile

Introduction

Heredity and the Dentition

Dentitions with Agenesis of Single Teeth

Dentitions with Multiple Tooth Agenesis

Dentitions with Macrodontic Maxillary Central Incisors

Dentitions with Supernumerary Teeth

Dentitions with Ectopic Canines

Dentitions with Transpositions

Dentitions with Arrested Eruption of Primary Molars

Dentitions Suitable for Tooth Transplantation

Dentitions with Arrested Eruption of Permanent Teeth

Dentitions with Persistence of a Primary Molar in Adulthood

Dentitions with Idiopathic Collum Resorption

Highlights and Clinical Relevance

Further Reading

Chapter 13: Craniofacial Syndromes and Malformations: Prenatal and Postnatal Observations

Holoprosencephaly/solitary median maxillary central incisor (SMMCI) syndrome

Cerebellar Hypoplasia/Cri-Du-Chat Syndrome

Myelomeningoceles/Spina Bifida and Hydrocephalus

Down's Syndrome (Trisomy 21)

Turner's Syndrome

Fragile X Syndrome

Crouzon's Syndrome

DiGeorge's/Velocardiofacial Syndrome

Cleft Lip and Palate

Comparison between Pre- and Postnatal Findings: Results and Restrictions

Malformations: Nonsyndromic Examples

Highlights and Clinical Relevance

Further Reading

Chapter 14: Craniofacial Disruptions: Prenatal and Postnatal Observations

Prenatal Disruptions

Postnatal Disruptions

Highlights and Clinical Relevance

Further Reading

Chapter 15: Craniofacial Dysplasia: Prenatal and Postnatal Observations

Endochondral and Intramembranous Bone Dysplasia in the Cranium

Dysplasia in Nonosseous Tissue

Highlights and Clinical Relevance

Further Reading

Chapter 16: Hard Tissue as a Diagnostic Tool in Medicine

Introduction

Perspectives for Prenatal Craniofacial Pathology

Perspectives for Perinatal and Pediatric Pathology

Perspectives for Clinical and Basic Research

Perspectives for Anthropology

Conclusion

Further Reading

Chapter 17: Clinical Cases and Unanswered Questions

Clinical Cases

Conditions in Diagnostics, Treatment Planning, and Outcome

Examples of Diagnostics and Treatment of Eruption Problems

Unanswered Questions

Further Reading

Index

End User License Agreement

List of Illustrations

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Etiology-Based Dental and Craniofacial Diagnostics

Inger Kjær

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Library of Congress Cataloging-in-Publication Data

Names: Kjær, Inger, author.

Title: Etiology-based dental and craniofacial diagnostics / Inger Kjær.

Description: Southern Gate, Chichester, West Sussex, UK ; Ames, Iowa : John

Wiley & Sons Inc., 2017. | Includes bibliographical references and index.

Identifiers: LCCN 2016018619| ISBN 9781118912126 (cloth) | ISBN 9781118912102

(ePub) | ISBN 9781118912119 (Adobe PDF)

Subjects: | MESH: Tooth Abnormalities–diagnosis | Skull–embryology |

Skull—growth & development

Classification: LCC RK308 | NLM WU 101.5 | DDC 617.6/3075–dc23 LC record available at https://lccn.loc.gov/2016018619

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Dedication

It is a great pleasure for me to dedicate this book to dentists and other professionals working in the community dental clinics in Denmark. I would like to take the opportunity to express my admiration for this public dental institution which serves nearly all of the children in the country.

A hearty thanks for:

Mutual collaboration and inspiration regarding diagnostics and treatment of patients in the clinic

The helpfulness and confidence that I have received over many years

Interest and support in this project for the benefit of our future patients.

Inger Kjær

Preface

What makes this book different from other textbooks on dental and craniofacial diagnostics?

This book is meant for clinicians, for pre- and postgraduate students, and for researchers in different fields of dental and craniofacial diagnostics. Every deviation in dental and craniofacial disorders, as described in this book, is based on embryological insight. Thus embryology is not restricted to an isolated chapter; insight from embryology and fetal pathology is applied throughout the entire book.

Etiology implies the cause or origin of a disease or disorder. In this book, the embryological origin is the foundation for the etiology-based postnatal diagnostics of disorders in the dentition and craniofacial region.

Every congenital condition has a developmental path from conception to late adulthood. If the etiology is known, there is a series of possibilities for predictions of development and treatment during the entire life span. Normal and pathological fetal development should in all medical disciplines be the biological basis for postnatal diagnostics. This way of thinking – from the very beginning and forward – is not restricted to medicine and odontology.

I would therefore like to end this foreword with a quote by Winston Churchill:

The further you can look back, the further you can look ahead.

Inger Kjær

Introduction

The scientific and clinical knowledge presented in this book is primarily based on personal research in normal and pathological prenatal cranial development combined with postnatal clinical experience in pediatrics, orthodontics, and diagnostics of rare human developmental conditions.

The purpose of this book is to focus on the etiology behind the clinical questions that are encountered in everyday practice, and which make diagnostics and treatment difficult. These questions include the following.

What is the mechanism behind tooth eruption? Can we explain this phenomenon?

How and when does the periodontal membrane develop?

After a tooth has emerged, it continues to erupt. What happens in the periodontal membrane during this continued eruption?

How is continued eruption associated with growth of the alveolar process?

Why do some areas in the jaws frequently contain abnormalities while others do not?

Can we explain correlations between findings in the maxilla and the mandible?

Why is there such a great difference between primary and permanent teeth regarding the occurrence of agenesis, resorption, and eruption?

What protects a permanent tooth root from resorption?

Are there similarities between the periodontal membrane of a primary tooth and the periodontal membrane of a permanent tooth?

Can signs in the primary dentition predict the later development of the permanent dentition?

How do diseases and/or the intake of medicine influence dental and craniofacial development?

All these central questions have had no clear answer until now. The issue has been that traditional research in the craniofacial region has been restricted by ethical, technical, and biological limits. In this book, experience from prenatal research is introduced and it is demonstrated how several but not all of these questions can be answered. The results presented are primarily based on the author's research referred to in the reference lists at the end of each chapter.

Limited Access to Human Material

Prenatal human studies only allow studies on spontaneous or medically induced abortions by special indications and permissions before gestational age (GA) 20 weeks. At this early stage, the roots of the primary teeth have not developed and the periodontal tissue is therefore not available for histological research. The cranium, however, is nearly completely formed and can be studied radiographically, histologically, and anthropologically. A main problem with prenatal tissue studies is that the tissue is often fragmented and it can be partially autolyzed.

Postnatal studies of the dentition are conducted clinically and are supplemented by radiological analysis, including three-dimensional (3D) analysis. These analyses concern tooth maturity and morphology. Migration of teeth before eruption can also be studied. Histological studies of normal tooth development can be done on extracted teeth, but in these cases the periodontium is often lacerated and it can be difficult to describe the structure. The entire periodontium surrounding a tooth can only be studied in autopsy materials or by surgical removal of a tooth and the surrounding tissue. Both cases provide a cross-sectional insight into a periodontal membrane which can be normal but which is most likely not normal. In cases of pathological tooth development where the tooth is removed, the specimens can provide information about the histomorphological diagnosis. Postnatally, the cranium can be studied using anthropological, radiographical, and histopathological methods.

The only studies that allow longitudinal observation are radiographical studies after birth. It is possible to conduct animal studies, but results from these studies cannot be transferred uncritically to human conditions.

Content and Structure of the Book

A book like this has not been written before. It concerns normal hard tissue development in the cranium and the dentition and creates a foundation for clinical diagnostics and for the etiology behind the diagnosis. Furthermore, this knowledge creates a basis for later genetic and molecular-biological research.

The book is structured into three main parts.

The first part includes chapters which cover different aspects of normal dental and craniofacial development. The text is supplemented with fetal pathology cases. These chapters cover the basic biological background for understanding abnormal patient cases. Such cases are demonstrated.

The second part (Chapter 7) demonstrates the obstacles faced in etiology-based diagnostics of the dentition and cranium. This part also introduces the international classification of abnormal development used in the final part of the book.

The third part covers abnormal development and focuses on the etiology behind everyday cases and unusual cases sporadically observed in the clinic. The text is again highlighted with fetal pathology cases. The final chapter discuss questions on the treatment of severe cases as well as cases in which the etiologies are still unsolved. It is hoped that this text will lead to thoughtful discussions and collaborations between professionals in the clinic and the science laboratory.

In each chapter, the why questions will be the focus. This applies to both normal and pathological developmental processes. Some explanations of these why questions have been documented. Others are still hypothetical and there are others that have no clear answer. This book has been written to promote the improvement of dental and craniofacial diagnostics and to provide ideas for future research.

Acknowledgments

As a student of former Professor Arne Björk and as a colleague of former Professor Beni Solow, I would like to acknowledge the valuable and inspiring scientific environment that these distinguished teachers created in the orthodontic department in Copenhagen for science, pioneer research and critical thinking during the years 1951–2000. Professor Björk inspired me to attack scientific problems nontraditionally and he gave me complete freedom through five years to develop my own way of thinking.

This book has become a reality due to collaboration between outstanding experts in widely varied subject fields: pedodontics, orthodontics, pediatrics, fetal pathology, anthropology, and multidisciplinary hospital units for cleft lip and palate treatment and rare human developmental conditions. It is therefore both an obligation and an honor for me to thank the following co-workers for their constant support for my research which has made this book possible.

Anatomy. Assoc. professor M. E. Matthiessen, DDS, MD is acknowledged for permission to use the laboratory facilities at the Department of Anatomy, University of Copenhagen, during a 5-years period, for fruitful collaboration and introduction to histochemistry.

Pedodontics. A large network of dentists working in the Danish healthcare systems for children and adults as well as dentists abroad have demonstrated cases for me and also inspired my studies by forwarding more than 2900 clinical inquiries.

Orthodontics. National and international specialists in orthodontics supported my studies by asking questions and by demonstrating difficult cases regarding orthodontic diagnostics and unexplainable treatment outcomes.

Pediatrics. Medical doctors in pediatrics are thanked for their collaboration. These are especially doctors in the fields of neuropediatrics and pediatric endocrinology. They appear as co-authors in the references of this book and have provided valuable input for craniofacial disorders.

Fetal pathology. Chief pathologist, Birgit Fischer Hansen, MD Dr Med, specialist in fetal pathology, has contributed tremendously to the concept of transferring the fields of embryology and fetal pathology to the clinic to allow improved diagnostics and treatments. Without Birgit Fischer Hansen's professional and encouraging support over many years, this book could not have been written.

Chief pathologist, Jean Keeling, MD, specialist in fetal pathology in the UK, has outstandingly supported the early research and promoted the international conceptualization of craniofacial diagnostics.

Several other pathologists specializing in fetal pathology are acknowledged for their support of my studies. Among these is chief pathologist Ingermarie Reintoft MD who introduced me to unique cases of malformations for which I am very grateful.

Professor in oral pathology, Jesper Reibel, DDS Dr Odont, is acknowledged for guidance in questions of oral pathology.

Anthropology. Colleagues at the medical museum, Medicinsk Museion, Copenhagen, have introduced me to the Saxthorp collection for which I am very grateful. Special thanks to the director of the museum, Professor PhD Thomas Söderqvist. Jan Jacobsen, DDS, and Pia Bennike, PhD and MSc, are both former anthropologists at the university whom I would like to acknowledge for supporting my studies in dental and craniofacial anthropology.

Hospital teams for rare developmental conditions. Kirsten Mølsted, DDS PhD, Head of the Cleft Lip and Palate Unit at Rigshospitalet, Copenhagen, is thanked for many fruitful years of collaboration and for scientific inspiration. Kirsten Mølsted has been an excellent colleague. Bjørn Russel, DDS, former Head of the Dental Clinic at Vangedehuse Children's Hospital for Severely Handicapped Children, is thanked for collaboration.

Jette Daugaard-Jensen, DDS and MS, Head of the Center for Rare Diseases at Rigshospitalet, Copenhagen, has through many years been a faithful and inspiring colleague whom I thank for scientific support.

Hans Gjørup, DDS and PhD, Head of the Center for Rare Diseases at Aarhus University Hospital, is thanked for being an excellent co-worker and colleague.

The outstanding collaboration over many years with biomedical laboratory technologist Dorrit Nolting, BA, who has prepared all the histological images in the book, is highly appreciated. Her skills, compassion, and dedication to tissue analysis have been essential for the results presented.

Linguistic support in several scientific papers forming the base for this book has been provided during the years 2002–2012 by Academic Secretary Maria Kvetny, MA. I am grateful for her many professional contributions in this respect.

Ghita Lemminger, Secretary for Postgraduate Education, was an excellent colleague during my time as Director of the Postgraduate Program until 2014.

A special thank you to Sarah Liv Fischer Richmond, medical student, for constant, professional, linguistic support and preparation of the manuscript for this book.

Inger Kjær

Chapter 1

Craniofacial Development and the Body Axis: Normal and Pathological Aspects From Early Prenatal to Postnatal Life

Body Axis Pre- and Postnatally

Germ Disk and Notochord

If you ask a dentist or a medical professional From where does the cranium develops in its initial phase? they will probably not be able to answer you. Going back to basic embryology, recall your memory of the germ disk. From this very early two-layered disk, the whole body arises. Gradually the mesoderm forms the third layer in the body and the notochord develops. The notochord is an axial row of cells of ectodermal origin which are decisive for the closure of the neural tube, formation of the central nervous system and visceral and skeletal development. The germ disk folds and begins to close centrally at approximately day 18 of gestational age (GA) and openings in the cranial and caudal ends arise (Figure 1.1). These openings are called neuropores.

Figure 1.1 (Upper) Schematic drawing of the early human embryonic formation of the germ disk (left), closure of the germ disk with a caudal neuropore, lower and upper cranial neuropores (center) and the neural tube (right). Yellow marks the central nervous system. The red line indicates the notochord and the green dot the prechordal plate (region of the later pituitary gland/sella turcica). The arrows mark directions of molecular signals from the notochord. (Lower) Schematic illustration of the location of the germ disk in the body, the neural tube and the contour of the early body development in the frontal plane (left) and in the midaxial plane (right).

Formation of the Vertebral Column

The ridges (left and right) that surround the cranial neuropore are called the neural crest (Figure 1.2). The neural crest cells are ectodermally derived and represent a contact ridge between the outer surface ectoderm and the inner neuroectoderm. The tissues that are derived from the neural crest are called the ectomesenchyme – having ectodermal origin with the ability to differentiate into various cell types, including connective tissue (e.g. cartilage, bone). From different regions on the neural crest, different ectomesenchymal cell groups migrate anteriorly through the fold between the neuroectoderm and the surface ectoderm, bulging out and gradually forming the craniofacial skeleton.

Figure 1.2 A schematic drawing of an embryo gestational age (GA) 4 weeks with an open cranial neuropore. Yellow contours mark the central nervous system and the colored dots mark the neural crest which borders the inner neuroepithelium and the outer surface epithelium. Red dots mark the frontonasal region of the crest. Green dots mark the maxillary and palatine regions and blue dots mark the mandibular region of the crest. Source: Drews (1995) reproduced with permission of Thieme Publishing Group.

More posterior parts of the cranium arise from tissue located laterally to the notochord, called paranotochordal tissue.

Gradually, the neuropores close and the germ disk forms the brainstem. From here the cerebral hemispheres develop from the foramen of Monro. Figure 1.3 depicts the craniofacial skeleton and the central nervous system.

Figure 1.3 A schematic drawing of the skeleton of a human fetus about GA 17 weeks. The spinal cord and the brainstem (not the cerebellum) are marked dark yellow, and the hemispheres of the cerebrum and cerebellum are marked beige. Green arrows indicate paths of neural crest cell migration to the jaws forming the green jaws and facial bones. White indicates the theca bones and the vertebral column. Red lines mark structures with an ectodermal origin which includes the notochord within the vertebral bodies. Peripheral nerves to the jaws are marked in orange.

The notochord forms the body axis at a very early stage (Figure 1.4). The notochord is essential for the folding and closing of the germ disk and for formation of body structures and the vertebral column. The bodies of the individual vertebrae form around the notochord (Figure 1.5). Remnants of notochordal tissue remain in the intervertebral disks after birth but not in the vertebrae. In the cranial portion of the body axis, the notochord ends in the region of the posterior wall of the sella turcica (Figure 1.6). Thus the notochord also organizes the main parts of the occipital bone and parts of the sphenoid bone corpus.

Figure 1.4 Midsagittal section of a part of the body axis of a human embryo GA 24 days demonstrating the early morphology of the notochordal cells (red).

Figure 1.5 A midsagittal section of the developing vertebral column in a human embryo GA 7 weeks. The cartilaginous vertebral bodies are marked purple. The notochord is a lightly marked (nearly white) cell structure centrally and vertically located within the vertebral bodies.

Figure 1.6 Profile radiograph of a child. The red line indicates the former location of the notochord from the vertebral bodies, through the basilar part of the occipital bone to the rostral location in the posterior wall of the sella turcica.

The sequence in which the vertebral bodies ossify is always the same, starting with the lumbosacral region and gradually moving cranially. The arches in the vertebrae protecting the medulla spinalis develop in a sequence which is also constantly the same, but the ossification of the arches starts cranially and moves gradually caudally. The region in which the ossification of the vertebral bodies and vertebral arches meet each other is near to the upper thoracic vertebra (Figure 1.7). In summary, the development of the head and brain is completely integrated with body axis development.

Figure 1.7 (Left) A schematic drawing of the entire body ossification of a human fetus GA 12 weeks. Note that several bones including bones in the head have started ossification. (Right) A radiographic image of the thoracic and cervical parts of the vertebral column in a human fetus GA 12 weeks. Note that the bodies of the cervical vertebrae have not ossified at this early stage. Source: Kjær et al. (1999). Reproduced with permission of John Wiley & Sons.

Fetal Pathology

Malformations in the vertebral bodies occur in relation to the notochord. These malformations could be twin bodies (completely separated body units) or partially cleft vertebral bodies. Also fusion between bodies or the absence of a vertebral body may occur. Different types of abnormal vertebrae are demonstrated in Figure 1.8.

Figure 1.8 Radiographic images of the vertebral bodies in a prenatal, human body axis. (Left) Lateral view GA 16 weeks. The bodies are complete or partially cleft. (Right) Frontal view GA 20 weeks. The lower bodies appear fused.

The mapping of the body axis in fetuses with different genetic abnormalities demonstrates that abnormal development often occurs regionally in so-called developmental fields. Thus fetuses with trisomy 18 predominantly have abnormalities in the thoracic and lumbosacral vertebral fields and not in the cervical field. This is not the case in trisomy 21, trisomy 13 or triploidy. Mapping of the body axis shows that the different genotypes affect the different fields in the vertebral column (Figure 1.9).

Figure 1.9 Schematic view of the body axis in a human fetus (left, lateral view; right, frontal view). The black contours marked from above: nasal bone, maxilla, sphenoid corpus, basilar occipital bone, corpora, arches of the vertebral column. (Right) Indication of malformed (red) and not malformed (green) areas in the body axis of a trisomy 18 fetus. Yellow indicates areas in which malformations sometimes occur. Source: Kjær et al. (1999). Reproduced with permission of John Wiley & Sons.

Cervical Spine Pre- and Postnatally

The bony bodies (corpora) of the cervical spine are formed by ossification of the cartilage encircling the early notochord. Remnants of the notochord may persist in the nucleus pulposus in the intervertebral disks. The arches of the vertebrae encircle the spinal cord. The atlas, which is the upper vertebra of the cervical spine, articulates with the occipital condyles on the external cranial base.

Figure 1.10 demonstrates the normal cervical spine in a child.

Figure 1.10 Radiograph from a child demonstrating the normal structures of the uppermost part of the body axis including the vertebral column, basilar occipital bone, and sella turcica.

Clinical Relevance

Prenatal defects are always present postnatally as well. Mapping of the malformations in the vertebral column is therefore essential for clinical diagnostics of postnatal vertebral development. Figure 1.11 demonstrates examples of malformations of the cervical column observed in children with known and unknown diagnoses.

Figure 1.11 Radiographic images from children with known and unknown diagnoses illustrating different malformations including