The Sutures of the Skull: Anatomy, Embryology, Imaging, and Surgery

Contents
Chapter 1: Introduction
	1.1 Introduction
	References
Chapter 2: The Sutures of the Skull: A Historical Perspective
	2.1 Introduction
	2.2 Homer and Mythological Era
	2.3 Hellenic Hippocrates Era
	2.4 Other Ancient Hellenic Studies
	2.5 American-African and Mediorient Ancient Studies
	2.6 Arabic World
	2.7 Medieval Times
	2.8 Nineteenth Century
	2.9 Modern Era
	2.10 Conclusion
	References
Chapter 3: Embryological and Histological Features of the Cranial Sutures
	3.1 Introduction
		3.1.1 An overview of the Embryonic Development of the Skeletal System and Skull
		3.1.2 An Overview of Ossification in the Skull Bones
	3.2 Development of Sutures
	3.3 Individual Bone Development and Ossification in Relation to Sutures
		3.3.1 Ossification Centers in Neurocranial Bones
			3.3.1.1 Frontal Bone
			3.3.1.2 Parietal Bone
			3.3.1.3 Occipital Bone
			3.3.1.4 Temporal Bone
			3.3.1.5 Sphenoid Bone
			3.3.1.6 Ethmoid Bone
			3.3.1.7 Additional Ossification Center and Sutural (Wormian) Bones
		3.3.2 Ossification Centers of the Viscerocranial Bones
			3.3.2.1 Maxilla
			3.3.2.2 Palatine Bone
			3.3.2.3 Os Zygomaticum
			3.3.2.4 Vomer
			3.3.2.5 The Other Viscerocranial Bones
			3.3.2.6 Histology of Cranial Sutures and Fontanelles
				Histology of Sutures
				Histology of Fontanelles
	3.4 Molecular Mechanisms and Clinical Reflections in Sutural Development
		3.4.1 Nonsyndromic Craniosynostosis
			3.4.1.1 Sagittal Synostosis
			3.4.1.2 Coronal Synostosis
			3.4.1.3 Metopic Synostosis
			3.4.1.4 Lambdoid Synostosis
		3.4.2 Syndromic Craniosynostosis
	3.5 Gene Mutations Associated with Craniosynostoses
		3.5.1 FGFR1, FGFR2 and FGFR3 Mutations
		3.5.2 Transforming Growth Factor β (TGF β) Mutations
		3.5.3 Mutations of Transcription Factors
		3.5.4 TWIST1 (twist-related protein 1) Mutations
	References
Chapter 4: Anatomy of the Sutures of the Calvaria
	4.1 Introduction
	4.2 Sutures of the Calvaria
		4.2.1 Metopic Suture (Frontal)
		4.2.2 Coronal Suture
		4.2.3 Lambdoid Suture
		4.2.4 Sagittal Suture
		4.2.5 Squamous Suture
		4.2.6 Accessory Parietal Suture
		4.2.7 Wormian Bone
	4.3 Clinical Relevance
		4.3.1 Fracture Versus Suture
	References
Chapter 5: Anatomy of the Sutures of the Skull Base
	5.1 Introduction
	5.2 Sutures of the Cranial Base
		5.2.1 Occipitomastoid Suture
		5.2.2 Parietomastoid Suture
		5.2.3 Mendosal Suture
		5.2.4 Sphenofrontal Suture
		5.2.5 Sphenosquamous Suture
		5.2.6 Sphenoethmoidal Suture
		5.2.7 Sphenoparietal Suture
		5.2.8 Petrosquamous Suture
		5.2.9 Sphenopetrosal Suture
		5.2.10 Sphenooccipital Suture
		5.2.11 Frontoethmoid Suture
	5.3 Clinical Relevance
		5.3.1 Craniosynostosis
		5.3.2 Basal Cranial Fractures
	References
Chapter 6: Anatomy of the Sutures of the Face
	6.1 Introduction
	6.2 Sutures of the Face
		6.2.1 Frontonasal Suture
		6.2.2 Frontoethmoidal Suture
	6.3 Frontolacrimal Suture
		6.3.1 Frontomaxillary Suture
		6.3.2 Frontozygomatic Suture
		6.3.3 Zygomaticomaxillary (infraorbital) Suture (Facial, Orbital, and Infratemporal Parts)
		6.3.4 Ethmoidomaxillary Suture
		6.3.5 Nasomaxillary Suture
		6.3.6 Internasal Suture
		6.3.7 Sphenozygomatic Suture
		6.3.8 Lacrimomaxillary Suture
		6.3.9 Ethmoidolacrimal Suture
		6.3.10 Intermaxillary Suture (Facial Part)
		6.3.11 Temporozygomatic Suture
		6.3.12 Palatomaxillary Suture (Nasal Part)
		6.3.13 Lacrimoconchal Suture
		6.3.14 Palatoethmoidal Suture
		6.3.15 Sphenovomerine Suture
		6.3.16 Sphenomaxillary Suture (Pterygomaxillary Suture)
		6.3.17 Sphenoethmoidal Suture
		6.3.18 Incisive Suture
		6.3.19 Median Palatine Suture
		6.3.20 Transverse Palatine Suture
	6.4 Clinical Relevance
		6.4.1 Cleft Palate
		6.4.2 Fractures Related to Sutures of the Face
			6.4.2.1 Le Fort I Fracture
			6.4.2.2 Le Fort II Fracture
			6.4.2.3 Le Fort III Fracture
			6.4.2.4 Naso-orbitoethmoid Fracture (NOE Fracture)
			6.4.2.5 Zygomaticomaxillary Complex Fracture (ZMC Fracture)
			6.4.2.6 Orbital Fractures
		6.4.3 Rapid Maxillary Expansion
	References
Chapter 7: Normal Growth of the Sutures of the Skull
	7.1 Suture and Synchondroses of the Skull: Identification
	7.2 Sutures and Synchondroses Are Cranial Growth Centers: Formation and Development
		7.2.1 Skull Development: Role of Sutures and Synchondroses
		7.2.2 Histology
		7.2.3 Stages of Sutural Growth and Closure
		7.2.4 Synchondroses Growth and Closure
	7.3 Assessment of Sutures and Synchondroses Growth: Role of CT and MRI
		7.3.1 CT and MRI: What Is the Best Technique?
		7.3.2 CT and MRI: Sensitivity and Specificity
		7.3.3 Assessment of Sutures Growth on CT
		7.3.4 Assessment of Sutures Growth in MRI
	7.4 Plastic Changes of Sutural Area During Closure and Fusion Processes
		7.4.1 Grading System of Closure
		7.4.2 Degree of Interdigitation: Sutural Patterns
	7.5 Sutures Fusion: Process and Timing
	References
Chapter 8: Variations in Sutural Anatomy of the Skull
	8.1 Metopic Suture Variations
	8.2 Epipteric Bone
	8.3 Coronal Suture
	8.4 Interparietal Bone
	8.5 Sagittal Suture Variations
	8.6 Variation in the Sutures of the Temporal Bone
	8.7 Lambdoid Suture Variations
		8.7.1 Os Incae
	8.8 Mendosal Suture
	8.9 Os Japonicum
	8.10 Infraorbital Suture
	8.11 Transverse Palatine Suture
	8.12 Miscellaneous Sutural Variations
	8.13 Conclusion
	References
Chapter 9: Metopism: Anatomical, Clinical and Surgical Aspects
	9.1 Introduction and Terminology
	9.2 Epidemiology
	9.3 Etiology
		9.3.1 Anatomical Aspects
	9.4 Relationship Between Metopism and the Frontal Sinus
		9.4.1 Clinical Aspects
		9.4.2 Surgical Aspects: Metopic Synostosis—Trigonocephaly
	References
Chapter 10: Skull Sutures as Anatomical Landmarks
	10.1 Skull Sutures
	10.2 Calvarial Sutures
		10.2.1 Coronal Suture
		10.2.2 Sagittal Suture
		10.2.3 Lambdoid Suture
		10.2.4 Squamosal Suture
		10.2.5 Occipitomastoid Suture
		10.2.6 Parietomastoid Suture
		10.2.7 Frontal Suture
	10.3 Facial Sutures (Fig. 10.9)
		10.3.1 Frontozygomatic Suture
		10.3.2 Frontomaxillary Suture
		10.3.3 Frontonasal Suture
		10.3.4 Temporozygomatic Suture
		10.3.5 Zygomaticomaxillary Suture
		10.3.6 Nasomaxillary Suture
		10.3.7 Sphenofrontal Suture
		10.3.8 Sphenozygomatic Suture
	10.4 Skull Point Landmarks
		10.4.1 Bregma
		10.4.2 Lambda
		10.4.3 Pterion
		10.4.4 Asterion
		10.4.5 Inion
		10.4.6 External Occipital Protuberance
		10.4.7 Basion and Opisthion
		10.4.8 Obelion
	References
Chapter 11: A Brief Introduction to the Biomechanics of Craniofacial Sutures
	11.1 Introduction
	11.2 Inherent Mechanical Properties of the Sutures
	11.3 Role and Function of the Sutures
	11.4 Response of Sutures to Mechanical Loads
	11.5 Discussion
	References
Chapter 12: Radiological Evaluation of the Sutures of the Skull
	12.1 Introduction
		12.1.1 Development of the Sutures
		12.1.2 Gross Anatomy: Sectioned Images
	12.2 Imaging Modalities
		12.2.1 Radiography
		12.2.2 Computed Tomography
		12.2.3 Magnetic Resonance Imaging
		12.2.4 Ultrasound
	12.3 Differential Diagnosis: Sutures and Fractures in Radiological Images
		12.3.1 Radiography
		12.3.2 Computed Tomography
	References
Chapter 13: The Biology of the Sutures of the Skull
	13.1 Introduction
	13.2 Components of the Cranial Suture
	13.3 Properties of the Cranial Suture, Compared to Bone
	13.4 Unique Skeletal Stem Cell Populations are Responsible for Maintenance and Repair
	13.5 Cranial Suture Mesenchymal Stem Cellsare Responsible for Craniofacial Bone Growth and Repair
	13.6 Cellular Processes Involved in Suture Morphogenesis
		13.6.1 Cell Death in the Suture Mesenchyme Leads to Cranial Suture Fusion
		13.6.2 Aberrant Cell Fate Specification of the Suture Mesenchyme Leads to Cranial Suture Fusion
	13.7 Interactions Between Neighboring Tissues
	13.8 Comparison of Cranial Sutures to Facial Sutures
	13.9 Conclusions and Perspectives
	References
Chapter 14: Types of Craniosynostosis and their Etiology, Pathophysiology and Epidemiology
	14.1 History
	14.2 Cranial and Facial Embryogenesis
	14.3 Epidemiology and Incidence
	14.4 Etiology
		14.4.1 Genetic Factors
		14.4.2 Metabolic Factors
		14.4.3 Epidemiological Factors
		14.4.4 Pathophysiology
		14.4.5 Impact over Cranial Cavity
		14.4.6 Ophthalmic Dysfunctions
		14.4.7 Impact over Intellectual Functions
		14.4.8 Epidemiological Characteristics
		14.4.9 Scaphocephaly
			14.4.9.1 Coronal Plagiocephaly or Unilateral Coronal Craniosynostosis
			14.4.9.2 Deformational Posterior Plagiocephaly
			14.4.9.3 Posterior Plagiocephaly (lamboid)
			14.4.9.4 Trigonocephaly
			14.4.9.5 Brachycephaly or Bilateral Coronal Craniosynostosis
			14.4.9.6 Oxycephaly
			14.4.9.7 Syndromatic Craniosynostosis
				Crouzon Syndrome
					Clinical and imaging characteristics
			14.4.9.8 Apert Syndrome
			14.4.9.9 Saethre-Chotzen Syndrome
				Clinical and Imaging Characteristics
			14.4.9.10 Pfeiffer Syndrome
				Clinical and Imaging Characteristics
			14.4.9.11 Cloverleaf Skull
	14.5 Treatment
		14.5.1 Surgical Treatment
			14.5.1.1 Classic Surgical Treatment
			14.5.1.2 Technical Details
			14.5.1.3 Scaphocephaly. Surgical treatment
			14.5.1.4 Brachycephaly. Surgical Treatment
			14.5.1.5 Trigonocephaly Surgical Treatment
			14.5.1.6 Plagiocephaly. Surgical Treatment
		14.5.2 Syndromic Craniosynostosis: Crouzon and Apert Syndromes. Surgical Treatment
			14.5.2.1 Endoscopic Surgery
			14.5.2.2 Helmets as an Adjacent Treatment
	References
Chapter 15: Genetic Features of Craniosynostosis
	15.1 Introduction
	15.2 Development and Growth of the Normal Cranial Vault
	15.3 Signaling Mechanisms Underlying the Pathophysiology of Craniosynostosis
	15.4 Genetics of Craniosynostosis
		15.4.1 Genetics of Syndromic Craniosynostosis
		15.4.2 Genetics of Non-Syndromic Craniosynostosis
	15.5 Genetic Counselling
	15.6 Conclusion
	References
Chapter 16: Imaging Modalities for Craniosynostosis
	16.1 Introduction
	16.2 Radiological Approach
		16.2.1 Preoperative Evaluation
			16.2.1.1 Confirmation of the Diagnosis
			16.2.1.2 Detection of Concomitant Anomalies
			16.2.1.3 Treatment Planning
			16.2.1.4 Prognosis Estimation
		16.2.2 Postoperative Evaluation
	16.3 Radiological Imaging Modalities
		16.3.1 Plain X-rays
		16.3.2 Computed Tomography
		16.3.3 Ultrasonography
		16.3.4 Magnetic Resonance Imaging
		16.3.5 Digital Angiography
	16.4 Conclusion
	References
Chapter 17: Syndromic Craniosynostosis
	17.1 Introduction
	17.2 Clinical Features
		17.2.1 Apert Syndrome
		17.2.2 Crouzon Syndrome
		17.2.3 Pfeiffer Syndrome
		17.2.4 Antley-Bixler Syndrome
		17.2.5 Muenke Syndrome
		17.2.6 Saethre–Chotzen Syndrome
		17.2.7 Cranio-Frontonasal Syndrome
	17.3 Radiology
		17.3.1 Plain Roentgenogram
		17.3.2 Multidetector Computed Tomography (MDCT) with Three-dimensional (3D) Volume Rendering
	17.4 MRI
		17.4.1 Follow-up Imaging
	17.5 Management
		17.5.1 Posterior Expansion
			17.5.1.1 Indication and Timing
			17.5.1.2 Procedure
		17.5.2 Anterior Advancement
		17.5.3 Fronto-orbital Advancement
			17.5.3.1 Indication and Timing
			17.5.3.2 Procedure
		17.5.4 Fronto-facial Advancement
		17.5.5 Complementary Procedures
			17.5.5.1 Barrel Staving
			17.5.5.2 Suturectomy
			17.5.5.3 Free Floating Bones
		17.5.6 Teamwork
		17.5.7 Complications
		17.5.8 Tips and Rules
	References
Chapter 18: Surgery for Craniosynostosis
	18.1 Introduction
	18.2 Indications for Surgery
	18.3 General Surgical Considerations
	18.4 Surgery for Nonsyndromic Craniosynotosis
		18.4.1 Metopic Synostosis (Trigonocephaly as Phenotypic Presentation)
			18.4.1.1 Diagnosis, and Indications for and Timing of Operative Treatment
			18.4.1.2 Preoperative Planing, Surgical Objectives and Special Equipment
			18.4.1.3 Anesthetic Considerations
			18.4.1.4 Operative Procedure
				Positioning
				Sterile Scrub, Draping and Local Anesthetic
				Skin Incision
				Initial Deconstructive Phase
				Subsequent Reconstructive Phase
				Closure
				Specific Instrumentation
			18.4.1.5 Postoerative Management
			18.4.1.6 Complications
			18.4.1.7 Outcome, Prognosis and Follow-up
		18.4.2 Unilateral and Bilateral Coronal Synostosis (Anterior or Frontal Unilateral and Bilateral Plagiocephaly, as Phenotypic Presentation)
			18.4.2.1 Unilateral Coronal Synosthosis (Anterior or Frontal Unilateral Plagiocephaly, as Phenotypic Presentation)
				Diagnosis, Indications, and Timing for Operative Treatment
				Preoperative Planning, Surgical Objectives and Special Equipment
				Anesthetic Considerations
				Operative Procedure
					Positioning
					Sterile Scrub, Draping and Local Anesthetic
					Skin Incision
					Initial Deconstructive Phase
					Subsequent Reconstructive Phase
					Closure
					Specific Instrumentation
			18.4.2.2 Postoperative Management
			18.4.2.3 Complications
				Outcome, Prognosis and Follow-up
			18.4.2.4 Bilateral Coronal Synostosis (Brachycephaly as Phenotypic Presentation)
				General Considerationds (Diagnosis, Surgery)
				Distraction Osteogenesis in Bicoronal Synostosis
				Closure
				Specific Instrumentation
				Postoperative Management
				Complications
				Outcome, Prognosis and Follow-up
		18.4.3 Sagittal Synostosis (Dolichocephaly, Scaphocephaly as Phenotypic Presentation)
			18.4.3.1 Diagnosis, Indications and Timing for Operative Treatment
			18.4.3.2 Preoperative Planning, Surgical Objectives and Special Equipment
			18.4.3.3 Anesthetic Considerations
			18.4.3.4 Operative Procedure
				Positioning
				Sterile Scrub, Draping and Local Anesthetic
				Skin Incision
				Initial Deconstructive Phase
				Closure
				Specific Instrumentation
			18.4.3.5 Postoperative Management
			18.4.3.6 Complications
			18.4.3.7 Outcome, Prognosis and Follow-up
			18.4.3.8 Lambdoid Synostosis (Posterior Plagiocephaly as Phenotypic Presentation)
			18.4.3.9 Diagnosis, Indications for Operative Treatment and Timing
			18.4.3.10 Preoperative Planning, Surgical Objectives and Special Equipment
			18.4.3.11 Anesthetic Considerations
			18.4.3.12 Operative Procedure
				Positioning
				Sterile Scrub, Draping and Local Anesthetic
				Skin Incision
				Initial Deconstructive Phase
				Additional Reconstructive Phase
				Closure
				Specific Instrumentation
			18.4.3.13 Postoperative Management
			18.4.3.14 Complications
			18.4.3.15 Outcome, Prognosis and Follow-up
	18.5 Surgery for Syndromic Craniosynosthosis
		18.5.1 Craniofacial Syndromes
			18.5.1.1 Crouzon Syndrome (Acrocephalosyndactyly Type II)
		18.5.2 Saethre-Chotzen Syndrome (acrocephalosyndactyly type III)
		18.5.3 Carpenter Syndrome
		18.5.4 Muenke Syndrome
		18.5.5 Cloverleaf Skull (Kleeblattschädel) Deformity
		18.5.6 Surgical Approaches and Treatments for Craniosynostosis
			18.5.6.1 Bilateral Coronal Synostosis
		18.5.7 Children Younger than 1 Year
		18.5.8 Children Older than 3 Years
		18.5.9 Children Between 1 and 3 Years of Age
			18.5.9.1 Posterior Vault Distraction
			18.5.9.2 Spring-assisted Cranioplasty
			18.5.9.3 Fronto-orbital Advancement
		18.5.10 Surgical Approaches and Treatments for Midface Hypoplasia
			18.5.10.1 Le Fort III Osteotomy
			18.5.10.2 Monobloc Advancement
			18.5.10.3 Distraction Osteogenesis of the Midface
		18.5.11 Surgical Approaches and Treatments for Hypertelorism
			18.5.11.1 Box Orbitotomy and Medial Orbit Translocation
			18.5.11.2 Facial Bipartition
		18.5.12 Complications in Surgery for Syndromic Craniosynostosis
	18.6 Conclusion
	References
Chapter 19: Experimental Animal Models in Cranial Suture Biology: Molecular and Pharmacological Treatment Strategies
	19.1 Introduction
	19.2 FGF/FGFR Signaling
	19.3 TGFβ/BMP Signaling
	19.4 Future Directions
	19.5 Summary
	References
Index