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Objective: The main objective of the study was to show the morphologic features of optic strut (OS) and prechiasmatic sulcus (PS) in the fetal skull base with a surgical anatomical perspective., Methods: Twenty-three fetal cadavers (9 female, 14 male) with an average age of 21.70 ± 3.12 (range: 16-28) weeks of gestation in the inventory of the Anatomy Department were included in the study. Measurements were made with a digital image analysis software and goniometer., Results: The sulcal length, interoptic distance, planum length, and sulcal angle were detected as follows: 3.91 ± 0.74 mm, 6.88 ± 1.04 mm, 6.55 ± 1.51 mm, and 24.52 ± 9.51°, respectively. Considering the location of the posteromedial margin of OS according to PS, OS was identified as the sulcal in 56.5% (13 cases), postsulcal in 30.4% (7 cases), and asymmetric in 13% (3 cases). According to the sulcal length and angle, PS was identified as type 1 in 26.1% (6 cases), type 2 in 21.7% (5 cases), type 3 in 30.4% (7 cases), and type 4 in 21.7% (5 cases)., Conclusions: Our findings suggest that the sulcal length and angle reach adult size in utero. Taking into account the fetal and the gathered adult measurements, the high percentage of steep angle compared to flat angle show that after birth, PS become more flat, probably depending on the variations of the sphenoid sinus pneumatization. Thus, more studies conducted on the alterations in PS and OS types relative to the pneumatization are needed in terms of patient positioning, selection of appropriate surgical approach, and intraoperative decision-making., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The modern human has the most flexed cranial base among all living animals. The flexure allowed a larger cranial volume to accommodate a greater brain. Spheno-occipitalis synchondrosis (SOS) has been largely responsible for cranial base flexion, between the sphenoid and the Pars basilaris of the occipital bone. The objective of this work is to evaluate the real place of skull base flexure. Analysis based on 50 magnetic resonance imaging from normal adult subjects were used to evaluate normal place for cranial base angulation (CBA). The vertex of the cranial base angle in all individuals occurred intrinsically in the sphenoid bone. In humans, cranial base flexure had a specific pre-chordal origin, rather than in the transition between pre-chordal and chordal plates and occurred in the inner sphenoidal bone.

Objectives: Skull base is an important and a challenging area for surgeons. Success in skull base surgery depends on various factors such as pre-operative evaluation, appropriate surgical technique, anesthesia duration, intraoperative neuromonitorization and wound care., Materials and Methods: This study was performed in the Anatomy dissection laboratory of M.U. Medical Faculty (Ethical committee approval number 2010-103). Twelve fetuses between 17-33 gestational weeks fixed with formaldehyde were enrolled to the study., Results: This study was planned to investigate the cross sectional areas of the sigmoid sinus in three levels to compare the right-left sides and the probable relationship among the levels in fetuses to further delineate the developmental factors on jugular foramen asymmetry. The cross-sectional measurements of sigmoid sinus lumen were done on 3 levels which are described as A1 level; sinodural angle, A2 level; the midpoint between the sinodural angle and endocranial orifice and A3 level as the entrance (endo-cranial orifice) of the jugular foramen. There is a strong positive correlation between left (L) A1 and L A2 and also the same for L A1 and right (R) A2. These strong and positive correlations are all valid between L A2-L A3, L A2-R A2, L A2-R A3, L A3-R A3, R A1-R A2., Conclusion: Multicenter studies would be beneficial to investigate the topic with greater number of fetuses also on the different regions for genetic differences.

The skull base is a part of the neuro-cranium formed by endochondral ossification. The embryological origin of the skull base is not perfectly known, but there seems to be an anterior region derived from the neural crest and a posterior part derived from the mesoderm. Further studies are needed to define reliable presumptive maps. The origin of the different components of the occipital bone is just as poorly known. Much fundamental work remains to be done to suggest any solution to these problems in humans., (Copyright © 2019 Elsevier Masson SAS. All rights reserved.)

Bone growth is linked to expansion of nearby organs, as is the case for the cranial base and the brain. Here, we focused on development of the mouse clivus, a sloping surface of the basioccipital bone, to define mechanisms underlying morphological changes in bone in response to brain enlargement. Histological analysis indicated that both endocranial and ectocranial cortical bone layers in the basioccipital carry the osteoclast surface dorsally and the osteoblast surface ventrally. Finite element analysis of mechanical stress on the clivus revealed that compressive and tensile stresses appeared mainly on respective dorsal and ventral surfaces of the basioccipital bone. Osteoclastic bone resorption occurred primarily in the compression area, whereas areas of bone formation largely coincided with the tension area. These data collectively suggest that compressive and tensile stresses govern respective localization of osteoclasts and osteoblasts. Developmental analysis of the basioccipital bone revealed the clivus to be angled in early postnatal wild-type mice, whereas its slope was less prominent in Tnfsf11 -/- mice, which lack osteoclasts. We propose that osteoclast-osteoblast "trans-pairing" across cortical bone is primarily induced by mechanical stress from growing organs and regulates shape and size of bones that encase the brain.

Background: As the skull base has a complex anatomy, we underline the importance of anomalies for side asymmetry. It is useful to investigate relationship between anatomical structures for the surgical procedure orientations. Dural adherence, enlarged superior petrosal sinus, influence of neural crest cells, and cranial base ossification are among the factors in morphometric growth on skull base., Material and Methods: Twenty-five fetuses of an estimated gestational age ranging from 17 to 34 weeks were studied in the Anatomy Laboratory of Mersin University Medical Faculty. Craniotomy was made to each fetus and brain hemispheres were dissected. We put plates, passing from the external points of lateral and anterior-posterior borders of fetus heads that are perpendicular to each other. An analytical calculation was formulated for the angle of foraminae to the root of zygoma by using different formulations depending on their posterior or anterior location to the root of zygoma. Statistical method was based on correlation analysis, simple regression, independent 2 group t tests, SPSS20.0, and MedCalc 11.5 (MedicReS, New York, NY)., Results: Neither side dominance for the jugular foramen, nor the differences of foramen rotundum, spinosum, and ovale to anterior skull wall, root of zygoma, and to midline were found to be significant., Conclusion: There is a debate on asymmetry of foramina of the skull base. No certain consensus about the initiation time and the causes of asymmetry in the past was documented. Studies are to be encouraged to further enlighten pre-postnatal factors affecting the fetal skull base morphometrism.

Introduction: The development of skeletal structures (cranial base, upper and lower) and upper airways spaces (oropharyngeal and nasopharyngeal) of the skull has always been an issue of great interest in orthodontics. Foetal MRI images obtained as screening exam during pregnancy can help to understand the development of these structures using a sample cephalometric analysis., Material and Methods: A total of 28 MRI images in sagittal section of foetuses from 20th to 32th weeks of gestation were obtained to dispel doubts about the presence of skeletal malformations. Cephalometric measurements were performed on MRI T2-dependent images acquired with a 1.5 T scanner. The Software Osirix 5 permits to study sagittal and vertical dimensions of the skull analysing linear measurements, angles and areas of the skeletal structures., Results: Vertical and sagittal dimension of cranial base, maxilla and mandible grow significantly (P < .01) between the second and third trimester of gestational period as well as nasopharyngeal and oropharyngeal spaces (P < .05). High correlation between the development of anterior cranial base and functional areas devoted to speech and swallow is demonstrated (r: .97)., Conclusions: The development of craniofacial structures during foetal period seems to show a close correlation between skeletal features and functional spaces with a peak between the second and third trimester of gestation. MRI images result helpful for the clinician to detect with a sample cephalometric analysis anomalies of skeletal and functional structures during prenatal period., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The current golden standard for treatment of craniomaxillofacial critical size bone defects, autologous bone grafting, is associated with several disadvantages which have prompted an increased demand for alternatives. New solutions are emerging in the form of bone tissue engineering. This involves harvesting of multipotent mesenchymal stromal cells (MSCs), after which they can be differentiated towards the osteogenic lineage mimicking intramembranous bone formation. However, translating this approach from laboratory to clinic has met with limited success. Consequently, attention has shifted towards investigation of the alternative endochondral route of bone regeneration. At a first glance, this approach may not appear logical for maxillofacial bone regeneration as most bones in the face originate from intramembranous mechanisms. Therefore, the goal of this review is to discuss the sense and non-sense of exploring endochondral bone regeneration as a novel reconstructive option for craniomaxillofacial bone defects. The embryological origin of craniomaxillofacial bone structures and their repair mechanisms are introduced. Also, the potential of MSC-like cells, the neural crest-derived stem cells from craniomaxillofacial sources, are discussed with a focus on regeneration of bone defects. Further, the current status of endochondral bone regeneration from MSCs is highlighted. Together, these aspects contribute in answering whether endochondral bone regeneration can be a logical approach to restore craniomaxillofacial bone defects., (Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

The cranial base is a component of the neurocranium and has a central role in the structural integration of the face, brain and vertebral column. Consequently, alteration in the shape of the human cranial base has been intimately linked with primate evolution and defective development is associated with numerous human facial abnormalities. Here we describe a novel recessive mutant mouse strain that presented with a domed head and fully penetrant cleft secondary palate coupled with defects in the formation of the underlying cranial base. Mapping and non-complementation studies revealed a specific mutation in Memo1 - a gene originally associated with cell migration. Expression analysis of Memo1 identified robust expression in the perichondrium and periosteum of the developing cranial base, but only modest expression in the palatal shelves. Fittingly, although the palatal shelves failed to elevate in Memo1 mutants, expression changes were modest within the shelves themselves. In contrast, the cranial base, which forms via endochondral ossification had major reductions in the expression of genes responsible for bone formation, notably matrix metalloproteinases and markers of the osteoblast lineage, mirrored by an increase in markers of cartilage and extracellular matrix development. Concomitant with these changes, mutant cranial bases showed an increased zone of hypertrophic chondrocytes accompanied by a reduction in both vascular invasion and mineralization. Finally, neural crest cell-specific deletion of Memo1 caused a failure of anterior cranial base ossification indicating a cell autonomous role for MEMO1 in the development of these neural crest cell derived structures. However, palate formation was largely normal in these conditional mutants, suggesting a non-autonomous role for MEMO1 in palatal closure. Overall, these findings assign a new function to MEMO1 in driving endochondral ossification in the cranium, and also link abnormal development of the cranial base with more widespread effects on craniofacial shape relevant to human craniofacial dysmorphology., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Some researchers contend that in adults the tensor tympani muscle (TT) connects with the tensor veli palatini muscle (TVP) by an intermediate tendon, in disagreement with the other researchers. To resolve this controversy, we examined serial sections of 50 human embryos and fetuses at 6-17 weeks of development. At 6 weeks, in the first pharyngeal arch, a mesenchymal connection was found first to divide a single anlage into the TT and TVP. At and after 7 weeks, the TT was connected continuously with the TVP by a definite tendinous tissue mediolaterally crossing the pharyngotympanic tube. At 11 weeks another fascia was visible covering the cranial and lateral sides of the tube. This "gonial fascia" had two thickened borders: the superior one corresponded to a part of the connecting tendon between the TT and TVP; the inferior one was a fibrous band ending at the os goniale near the lateral end of the TVP. In association with the gonial fascia, the fetal TT and TVP seemed to provide a functional complex. The TT-TVP complex might first help elevate the palatal shelves in association with the developing tongue. Next, the tubal passage, maintained by contraction of the muscle complex, seems to facilitate the removal of loose mesenchymal tissues from the tympanic cavity. Third, the muscle complex most likely determined the final morphology of the pterygoid process. Consequently, despite the controversial morphologies in adults, the TT and TVP seemed to make a single digastric muscle acting for the morphogenesis of the cranial base., (© 2016 Wiley Periodicals, Inc.)

Introduction: The formation of the occipital bone is intricate and has been extensively studied with many controversial conclusions, but with minimal effort being focused on the genes and molecular interactions necessary for its formation. A better understanding of this bone of the calvarial and skull base may shed light on pathologies where the occiput is often considered the offending entity., Methods: A review of the germane medical literature using textbooks and standard search engines was performed to gather information about previous conclusions as it pertains to the embryology and ossification of the occipital bone., Results: The occipital bone has both membranous and cartilaginous origin with ossification occurring as early as week 9 of fetal gestation. Its formations is dependent on complex interacts between genes and molecules with pathologies resulting from disruption of this delicate process., Conclusion: There has been much controversy in the past in regards to the development and ossification process necessary for occipital bone formation, which has only recently been clarified with documentation of the genes and molecular interactions necessary for its formation. Lastly, this improved knowledge might improve our understanding of such congenital derailments as the Chiari malformations.

Craniofacial malformations are common congenital defects caused by failed midline inductive signals. These midline defects are associated with exposure of the fetus to exogenous teratogens and with inborn genetic errors such as those found in Down, Patau, Edwards' and Smith-Lemli-Opitz syndromes. Yet, there are no studies that analyze contributions of synchronous neurocranial and neural development in these disorders. Here we present the first in-depth analysis of malformations of the basicranium of a holoprosencephalic (HPE) trisomy 18 (T18; Edwards' syndrome) fetus with synophthalmic cyclopia and alobar HPE. With a combination of traditional gross dissection and state-of-the-art computed tomography, we demonstrate the deleterious effects of T18 caused by a translocation at 18p11.31. Bony features included a single developmentally unseparated frontal bone, and complete dual absence of the anterior cranial fossa and ethmoid bone. From a superior view with the calvarium plates removed, there was direct visual access to the orbital foramen and hard palate. Both the eyes and the pituitary gland, normally protected by bony structures, were exposed in the cranial cavity and in direct contact with the brain. The middle cranial fossa was shifted anteriorly, and foramina were either missing or displaced to an abnormal location due to the absence or misplacement of its respective cranial nerve (CN). When CN development was conserved in its induction and placement, the respective foramen developed in its normal location albeit with abnormal gross anatomical features, as seen in the facial nerve (CNVII) and the internal acoustic meatus. More anteriorly localized CNs and their foramina were absent or heavily disrupted compared with posterior ones. The severe malformations exhibited in the cranial fossae, orbital region, pituitary gland and sella turcica highlight the crucial involvement of transcription factors such as TGIF, which is located on chromosome 18 and contributes to neural patterning, in the proper development of neural and cranial structures. Our study of a T18 specimen emphasizes the intricate interplay between bone and brain development in midline craniofacial abnormalities in general., (© 2015 Anatomical Society.)

Chordomas are malignant tumors of the axial skeleton, characterized by their locally invasive and slow but aggressive growth. These neoplasms are presumed to be derived from notochordal remnants with a molecular alteration preceding their malignant transformation. As these tumors are most frequently observed on the skull base and sacrum, patients suffering from a chordoma present with debilitating neurological disease, and have an overall 5-year survival rate of 65%. Surgical resection with adjuvant radiotherapy is the first-choice treatment modality in these patients, since chordomas are resistant to conventional chemotherapy. Even so, management of chordomas can be challenging, as chordoma patients often present with recurrent disease. Recent advances in the understanding of the molecular events that contribute to the development of chordomas are promising; the most novel finding being the identification of brachyury in the disease process. Here we present an overview of the current paradigms and summarize relevant research findings., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Introduction: The skull base represents a central and complex bone structure of the skull and forms the floor of the cranial cavity on which the brain lies. Anatomical knowledge of this particular region is important for understanding several pathologic conditions as well as for planning surgical procedures. Embryology of the cranial base is of great interest due to its pronounced impact on the development of adjacent regions including the brain, neck, and craniofacial skeleton., Materials and Methods: Information from human and comparative anatomy, anthropology, embryology, surgery, and computed modelling was integrated to provide a perspective to interpret skull base formation and variability within the cranial functional and structural system., Results and Conclusions: The skull base undergoes an elaborate sequence of development stages and represents a key player in skull, face and brain development. Furthering our holistic understanding of the embryology of the skull base promises to expand our knowledge and enhance our ability to treat associated anomalies.

Introduction: We aimed to investigate the morphometric development of the cranial base and its related structures, and their growth rate changes from the ninth gestational week to full term in a large group of human fetuses., Methods: We selected 203 (109 male, 94 female) fetuses between 9 and 40 weeks of gestation and without any external anomalies. From each fetus, standard lateral and posteroanterior cephalometric images were taken using a dental digital panoramic and cephalometric x-ray machine. Fourteen linear and 9 angular parameters were measured., Results: The cranial base angle showed a statistically significant increase between the groups from only the second to the third trimester periods. The sagittal translation of the maxilla increased during the prenatal period, whereas the mandibular sagittal relation grew at a steady rate. The vertical plane angles of the maxilla and the mandible did not show any significant changes. The maxillary length to mandibular length ratio remained stable., Conclusions: The cranial base angle increased, especially in the second through the third trimesters. The maxilla and the mandible demonstrated different growth patterns in the sagittal direction. The findings of this study could be a guide for interpreting the relationships among the craniofacial structures., (Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.)

Introduction: Brain growth plays likely an important role for the skull growth. In the fetus, there exists an heterochrony for the growth of supratentorial (forebrain) and infratentorial regions (brainstem and cerebellum). The aim of the study was thus to model geometrically the growth of these two regions and to compare it with the inflection of the base of skull., Material and Methods: Brain growth measurements were performed from midsagittal photographs of fetal brains obtained from an Anatomical Atlas over a period from 10 to 40 amenorrhea weeks (AW). After countouring and pointing anatomical and geometrical landmarks, we have developed a linear growth model based on principal component analysis (PCA). Besides, the variation of the sphenoidal and clivo-foraminal angles was studied from anatomical midsagittal slices of fetal heads sampled over a period from 16 to 39 AW., Results: The PCA model brings to light the radial expansion of the forebrain growth (first component) associated with an inferior and posterior rotation of the occipital lobe. The growth of the infratentoriel region presents an inferior and posterior expansion associated with a second component corresponding to inferior and anterior expansions. From the 17 AW, appears an heterochrony between the supra- and infratentorial growths and an inversion of the ratio between the infra- and supratentorial dimensions after 30 AW. The sphenoidal and clivo-foraminal angles decrease slightly until 25 AW, and then increase quickly until the 39 AW., Conclusions: The growth of brain is accompanied by morphological change between the compartments supra- and infratentoriel but also on the level of the base of skull. The possible interactions will be discussed., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Objective: The intent of this study was to evaluate the effect of plastination on the morphology and structure of stored organs, to find out how much accuracy a plastinated specimen has, and to look into the changes that occurred because of plastination., Materials and Methods: A human fetus of gestational age 24 weeks was plastinated, and 3D CT scan evaluation of the fetus was done., Results: The results showed normal, well-defined, clearly identifiable organs, with no alteration in morphology and structure of organs., Conclusion: In our opinion, plastinated specimens are better way of visualization of morphology and structure of stored organs, which is a useful tool for teaching as well as for research purposes.

Background: Eagle's syndrome refers to a rare constellation of neuropathic and vascular occlusive symptoms caused by pathologic elongation or angulation of the styloid process and styloid chain. First described in 1652 by Italian surgeon Piertro Marchetti, the clinical syndrome was definitively outlined by Watt Eagle in the late 1940s and early 1950s., Methods: This article reviews how underlying embryologic and anatomic pathology predicts clinical symptomatology, diagnosis, and ultimately treatment of the syndrome., Results: The length and direction of the styloid process and styloid chain are highly variable. This variability leads to a wide range of relationships between the chain and the neurovascular elements of the neck, including cranial nerves 5, 7, 9, and 10 and the internal carotid artery. In the classic type of Eagle's syndrome, compressive cranial neuropathy most commonly leads to the sensation of a foreign body in the throat, odynophagia, and dysphagia. In the carotid type, compression over the internal carotid artery can cause pain in the parietal region of the skull or in the superior periorbital region, among other symptoms., Conclusions: Careful recording of the history of the present illness and review of systems is crucial to the diagnosis of Eagle's syndrome. After the clinical examination, the optimal imaging modality for styloid process pathology is spiral CT of the neck and skull base. Surgical interventions are considered only after noninvasive therapies have failed, the two most common being intraoral and external resection of the styloid process.

Conclusions: 1. The principle of bilateral symmetry depends on the chordal cartilage that is the keystone in cranial base ossification in rats and humans, due to its anatomical situation and for the production of the chordin protein that regulates the bone morphogenetic protein BMP-7. 2. In humans and in rats, foramen lacerum closure follows a line of intramembranous ossification that depends on BMP-7, regulated by the first branchial pouch. 3. The cranial base ossification patterns and centres are similar in humans and in rats, except in the otic capsule, palate and the lateral pterygoid plate. 4. The neural crest may induce cranial ossification through the cranial nerves., Objectives: To study the patterns of cranial base ossification in humans and in rats, considering the chordal cartilage, and the otic, nasal and orbit capsules, as well as the participation of the branchial arches and pouches., Methods: This was a light microscopy study of human fetal specimens obtained from spontaneous abortions with the following crown-rump-lengths (crl) 45, 74, 90, 134, 145 and 270 mm, and a 1-day-old neonate (360 mm crl), who had died of sudden death syndrome. We also examined Webster albino rat embryos of 16, 18 and 20 days of gestation and a postnatal series of rats 8 h and 1, 3, 4, 6, 7, 10 and 13 days old, as well as adult animals., Results: In the 45 mm human fetus, the chordal cartilage with the nasal, otic and orbit capsules initiates cranial base ossification. Foramen lacerum closure begins in the 16-day-old rat embryo, following a line of membranous ossification between the external pterygoid process and the lateral alisphenoidal wing at ovalis foramen level. This is not a timing symmetrical process, which may persist until the 10th postnatal day in the rat. In the human fetus of 74 mm, the foramen lacerum space is closed by a membranous fusion ossification between the chordal cartilage and otic capsule, finishing at the 270 mm specimen. Endochondral ossification of the human otic capsule first appeared in the 145 mm (18 weeks) fetal specimen with four ossifying centres. The rat otic cartilaginous capsule showed rapid endochondral ossification, in the third and fourth postnatal day specimens.

Maxillofacial dysmorphogenesis is found in 5% of the population. To begin to understand the mechanisms required for maxillofacial morphogenesis, we employed the inhibitors of the differentiation 2 (Id2) knock-out mouse model, in which Id proteins, members of the regulator of basic helix-loop-helix (bHLH) transcription factors, modulate cell proliferation, apoptosis, and differentiation. We now report that spatially-restricted growth defects are localized at the skull base of Id2 KO mice. Curiously, at birth, neither the mutant Id2 KO nor wild-type (WT) mice differed, based upon cephalometric and histological analyses of cranial base synchondroses. In postnatal week 2, a narrower hypertrophic zone and an inhibited proliferative zone in presphenoid synchondrosis (PSS) and spheno-occipital synchondrosis (SOS) with maxillary hypoplasia were identified in the Id2 mutant mice. Complementary studies revealed that exogenous bone morphogenetic proteins (BMPs) enhanced cartilage growth, matrix deposition, and chondrocyte proliferation in the WT but not in the mutant model. Id2-deficient chondrocytes expressed more Smad7 transcripts. Based on our results, we assert that Id2 plays an essential role, acting downstream of BMP signaling, to regulate cartilage formation at the postnatal stage by enhancing BMP signals through inhibiting Smad7 expression. As a consequence, abnormal endochondral ossification was observed in cranial base synchondroses during the postnatal growth period, resulting in the clinical phenotype of maxillofacial dysmorphogenesis., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The retinoic acid (RA) signaling pathway is known to play important roles during craniofacial development and skeletogenesis. However, the specific mechanism involving RA in cranial base development has not yet been clearly described. This study investigated how RA modulates endochondral bone development of the cranial base by monitoring the RA receptor RARγ, BMP4, and markers of proliferation, programmed cell death, chondrogenesis, and osteogenesis. We first examined the dynamic morphological and molecular changes in the sphenooccipital synchondrosis-forming region in the mouse embryo cranial bases at E12-E16. In vitro organ cultures employing beads soaked in RA and retinoid-signaling inhibitor citral were compared. In the RA study, the sphenooccipital synchondrosis showed reduced cartilage matrix and lower BMP4 expression while hypertrophic chondrocytes were replaced with proliferating chondrocytes. Retardation of chondrocyte hypertrophy was exhibited in citral-treated specimens, while BMP4 expression was slightly increased and programmed cell death was induced within the sphenooccipital synchondrosis. Our results demonstrate that RA modulates chondrocytes to proliferate, differentiate, or undergo programmed cell death during endochondral bone formation in the developing cranial base., (Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.)

Congenital anomalies of the brain frequently correspond to cranial base anomalies, and a detailed description of morphology and individual variations in the developing cranial base is of clinical importance for diagnosing anomalies. Development of the human cranial base has been studied using dissection, computed tomography, and magnetic resonance imaging, each of which has advantages and disadvantages. We here examined development of the normal human fetal cranial base using bone staining, which allows for direct observation of the ossification centers and precise three-dimensional measurements. We observed alizarin red S-stained sphenoids and basiocciputs of 22 normal formalin-fixed human fetuses with crown-rump lengths (CRL) of 115-175 mm. We defined landmarks and measured sphenoids and basiocciputs using a fine caliper. Growth patterns of these ossifying bones were obtained, and we found similarities and differences among the growth patterns. We also observed individual variations in the ossification patterns, in particular, single- or double-ossification center patterns for the basisphenoid. The orbitosphenoid and basisphenoid widths and ratios of the widths to the total cranial base width were significantly different between the two pattern groups, whereas the other measurements and their ratios to the total cranial base did not differ between the groups. We measured the cerebrum and pons in different sets of 22 human fetuses with CRLs of 105-186 mm and found close relationships with the development of corresponding parts of the cranial base. The results contribute to the quantitative and qualitative information about the growth patterns and variations during human fetal cranial base development., (© 2011 The Authors. Congenital Anomalies © 2011 Japanese Teratology Society.)

Objectives: Cranial base development during fetal life is of major interest for many research purposes. In this study, we focused on fetal age estimations which are extremely important in forensic contexts. Nevertheless, there have been very few studies using occipital measurements to determine fetal age., Objectives: To evaluate change in the sagittal length/maximum width ratio of the basilar part of the occipital bone and to propose a simple and reliable method for fetal age determination., Methods: A sample of 30 male and 7 female fetuses aged 24 to 41 weeks amenorrhea underwent CT scan. Occipital bones were reconstructed (Amira 4.0) and measurements were carried out on each part., Results: A multivariate analysis (ANOVA) gave an age formula using right exoccipital measurements and a linear regression supplied the age of reversion of the sagittal length/maximum width ratio., Conclusion: This preliminary study clearly highlighted the promises of 3D CT-Scan studies of fetal cranial base and gave interesting results and the method deserves to be tested on a larger sample.

Objectives: We wished to develop an ultrasound cephalometric analysis, particularly of the antero-posterior jaw relationship, to increase the accuracy of prenatal diagnosis of retrognathism during the routine midterm test., Methods: Anatomical cephalometric analysis was performed in 18 formalin-fixed human fetuses (between 16 and 39 gestational weeks), and ultrasound cephalometry was prospectively carried out in 52 pregnant women (21 to 25 gestational weeks). The same landmarks were used in the anatomical and ultrasound median sagittal planes for comparison. Four cephalometric angles were measured relative to the anterior cranial base: alveolar projection of the maxilla and the mandible, chin projection, and facial angle. The antero-posterior jaw discrepancy was calculated., Results: The projection of the maxilla was similar in the two cephalometric analyses (IC [-3.39, 0.23]), whereas the values of the projection of the mandible were lower in the ultrasound sample. The slope of the regression line of the antero-posterior jaw discrepancy on fetuses' age did not show significant differences (IC [-0.05, 1.54]) between anatomical and ultrasound cephalometry, although a difference of 3.23° ± 0.78° (IC [1.69, 4.77]) was observed. Despite this variability, the projections of mandible and chin were well determined by the projection of the maxilla both in the anatomical and ultrasound sample., Conclusions: Cephalometric analysis by prenatal sonography can be performed to study the antero-posterior jaw relationship. We think that this procedure could be useful to improve prenatal diagnosis of retrognathism in high-risk pregnancies. Further studies should address the reproducibility and accuracy of such analysis.

The vertebrate cranial base is a complex structure composed of bone, cartilage and other connective tissues underlying the brain; it is intimately connected with development of the face and cranial vault. Despite its central importance in craniofacial development, morphogenesis and tissue origins of the cranial base have not been studied in detail in the mouse, an important model organism. We describe here the location and time of appearance of the cartilages of the chondrocranium. We also examine the tissue origins of the mouse cranial base using a neural crest cell lineage cell marker, Wnt1-Cre/R26R, and a mesoderm lineage cell marker, Mesp1-Cre/R26R. The chondrocranium develops between E11 and E16 in the mouse, beginning with development of the caudal (occipital) chondrocranium, followed by chondrogenesis rostrally to form the nasal capsule, and finally fusion of these two parts via the midline central stem and the lateral struts of the vault cartilages. X-Gal staining of transgenic mice from E8.0 to 10 days post-natal showed that neural crest cells contribute to all of the cartilages that form the ethmoid, presphenoid, and basisphenoid bones with the exception of the hypochiasmatic cartilages. The basioccipital bone and non-squamous parts of the temporal bones are mesoderm derived. Therefore the prechordal head is mostly composed of neural crest-derived tissues, as predicted by the New Head Hypothesis. However, the anterior location of the mesoderm-derived hypochiasmatic cartilages, which are closely linked with the extra-ocular muscles, suggests that some tissues associated with the visual apparatus may have evolved independently of the rest of the "New Head".

Objective: To determine the anatomy of the soft and hard palate during fetal growth in order to improve its ultrasonographic prenatal visualization., Design: Anatomic study in human formalin-fixed fetus., Methods: The heads of 18 second and third trimester fetuses were studied in the median sagittal plan. Measurements of the soft palate, the velopharynx, the root of the tongue, and the oral floor were taken. The hard palate/soft palate angle and the anterior cranial base/soft palate angle were measured., Results: The growth of the hard palate was linear, and the growth of the soft palate was polynomial (second order) during the period studied. The hard palate/soft palate angle was 150.33 degrees +/- 7.62 and 150.20 degrees +/- 6.67 in the second and third trimester, respectively. The anterior position of the soft palate in relation to the anterior cranial base was 48.8 degrees +/- 3.13 in the second trimester and 52.26 degrees +/- 3.31 in the third trimester. Its posterior position was 89.66 degrees +/- 5.51 in the second trimester and 92.97 degrees +/- 4.01 in the third trimester. Throughout the fetal period, the soft palate moved downward relative to the clivus and cervical spine., Conclusions: Despite the nonlinear growth and downward displacement of the soft palate during fetal life, its position remains stable. These results may be useful to explore the fetal soft palate using 2D and 3D ultrasonography and to improve the prenatal diagnosis of isolated cleft palate.

Objective: To explore longitudinally the development of the fetal skull base using three-dimensional (3D) sonography., Methods: Serial 3D sonographic measurements of anterior skull base length, posterior cranial fossa length and skull base angle were made in 126 normal singleton pregnancies at 18-34 weeks of gestation. In a sub-study of 22 pregnancies, intraobserver variability was determined. Regression analysis for repeated measurements was performed by means of the random coefficients model. Results from an earlier publication on brain volume were extended to the total patient cohort., Results: Measurements were technically successful in 69-94% of cases. The coefficient of variation for differences between repeated tests within women was 3.5-7.6% and between repeated analyses of the same recorded volume it was 3.0-5.1%. A statistically significant gestational age-related increase was established for both the anterior skull base length and the posterior cranial fossa length and the skull base angle showed a small but significant flexion of about 6 degrees . A higher increment in posterior cranial fossa length relative to anterior skull base angle was established. A significant quadratic relationship could be established for both anterior skull base length (P < 0.0001) and posterior cranial fossa length (P < 0.0001) but not for skull base angle, relative to brain volume., Conclusion: The reproducibility was acceptable for all fetal skull base measurements. The more pronounced growth in posterior cranial fossa length relative to anterior skull base length is influenced by brain growth. The small flexion of the skull base angle, however, may be caused by other factors. Published by John Wiley & Sons, Ltd., (Copyright (c) 2007 ISUOG.)

The cranial base is formed by endochondral ossification and is characterized by the presence of the synchondrosis growth centers. The aim of this study was to describe the histological development of the mouse midsagittal cranial base area from embryonic day 10 (E10) to the postnatal age of 2 months. The Bmp family of signaling molecules serves important functions in embryo and bone development and may therefore play a significant role in the early formation of the cranial base. To investigate this, we analyzed the mRNA pattern of expression of Bmp2-6 in the mouse cranial base from E10 to 5 days postnatally using radioactive in situ hybridization. We found that the formation of the mouse cranial base corresponds to that of rat and proceeds in a caudorostral sequence. Moreover, all Bmps studied showed distinct and overlapping developmentally regulated expression domains. Bmp2, Bmp5, and Bmp6 were expressed in the early mesenchymal condensations. Later, Bmp2, Bmp3, Bmp4, and Bmp5 were detected in the perichondrium and in the adjacent mesenchyme. Subsequently, Bmp2 and Bmp6 expressions were confined to hypertrophic chondrocytes, while Bmp3, Bmp4, and Bmp5 were expressed in the osteoblasts of the trabecular bone and bone collar. Interestingly, Bmp3 was uniquely expressed postnatally in the resting zone of the synchondrosis growth center, suggesting a role in the regulation of cranial base growth. These results suggest that Bmp signaling may serve specific and synergistic functions at different key stages of cranial base development and growth., (Copyright (c) 2006 Wiley-Liss, Inc.)

The synchondroses consist of mirror-image growth plates and are critical for cranial base elongation, but relatively little is known about their formation and regulation. Here we show that synchondrosis development is abnormal in Indian hedgehog-null mice. The Ihh(-/-) cranial bases displayed reduced growth and chondrocyte proliferation, but chondrocyte hypertrophy was widespread. Rather than forming a typical narrow zone, Ihh(-/-) hypertrophic chondrocytes occupied an elongated central portion of each growth plate and were flanked by immature collagen II-expressing chondrocytes facing perichondrial tissues. Endochondral ossification was delayed in much of the Ihh(-/-) cranial bases but, surprisingly, was unaffected most posteriorly. Searching for an explanation, we found that notochord remnants near incipient spheno-occipital synchondroses at E13.5 expressed Sonic hedgehog and local chondrocytes expressed Patched, suggesting that Shh had sustained chondrocyte maturation and occipital ossification. Equally unexpected, Ihh(-/-) growth plates stained poorly with Alcian blue and contained low aggrecan transcript levels. A comparable difference was seen in cultured wild-type versus Ihh(-/-) synchondrosis chondrocytes. Treatment with exogenous Ihh did not fully restore normal proteoglycan levels in mutant cultures, but a combination of Ihh and BMP-2 did. In summary, Ihh is required for multiple processes during synchondrosis and cranial base development, including growth plate zone organization, chondrocyte orientation, and proteoglycan production. The cranial base appears to be a skeletal structure in which growth and ossification patterns along its antero-posterior axis are orchestrated by both Ihh and Shh.

MicroRNAs (miRNA) are short RNA molecules regulating the expression of specific mRNAs. We investigated the expression pattern and potential targets of mouse miR-140 and found that miR-140 is specifically expressed in cartilage tissues of mouse embryos during both long and flat bone development. MiR-140 expression was detected in the limbs of E11.5 embryos in the primorida of future bones both in the fore and hindlimb and across autopod, zeugopod and stylopod. All digits of E14.5 fore- and hindlimbs showed accumulation of miR-140, except the first digit of the hindlimb. MiR-140 expression was also detected in the cartilagenous base of E17.5 skulls and in the sternum, the proximal rib heads and the developing vertebral column of E15.5 embryos. A potential target of miR-140, histone deacetylase 4, was validated experimentally and the possible role of miR-140 in long bone development is discussed.

Background: SOX9 is a critical transcription factor for chondrogenesis and sex determination. Haploinsufficiency mutations of Sox9 in humans lead to campomelic dysplasia. Inactivation of Sox9 in the craniofacial region of mice results in an absence of endochondral bones and in malformation of other structures. This suggests that Sox9 plays multiple roles in craniofacial development and these remain to be elucidated. In order to study the functions of Sox9 in craniofacial development, a preliminary expression examination was performed., Material and Methods: To detect the expression of Sox9 mRNA, antisense riboprobe was synthesized by in vitro transcription. Radioactive in situ hybridization was performed on sagittal and coronal sections of mice head from organogenesis to the early postnatal stage., Results: It was found that Sox9 was expressed in multiple stages and distinct processes. Besides the expression in cartilage, it was seen in the fusing stage of palatogenesis. Sox9 was also present during differentiation and maturation of craniofacial muscles. In addition, it was observed in intramembranous skeletal elements at restricted sites and stage., Conclusions: The expression pattern suggests that Sox9 serves broad roles in craniofacial development.

The cranial base, located between the cranial vault and the facial bones, plays an important role in integrated craniofacial development and growth. Transgenic Shh and Sox9-deficient mice show similar defects in cranial base patterning. Therefore, in order to examine potential interactions of Shh, Ihh, another member of the Hh family, and Sox9 during cranial base development and growth, we investigated their cellular mRNA expression domains in the embryonic (E) and early postnatal (PN) cranial base from E10 to PN5 using sectional radioactive 35-S in situ hybridization. Of the Hhs, Shh was observed in the foregut epithelium and the notochord, while Sox9 showed broad expression in the loose mesenchyme of the cranial base area during E10-E11. Subsequently, from E12 onward, all genes were observed in the developing cranial base, and after birth the genes were prominently colocalized in the prehypertrophic chondrocytes of the synchondroses. Collectively, these data suggest that Hh-Sox9 auto- and paracrine signaling interactions may provide a critical mechanism for regulating the patterning of the cranial base as well as for its development and growth.

Growth hormone (GH) secretion affects bone and cartilage physiology. This study investigated the effect of GH on the size of the craniofacial structures and their angular relationship. Three different models of mice with a genetically altered GH axis were used: GH excess (giant), dwarf GH antagonist (dwarf-Ant), and dwarf GH receptor knockout (dwarf-KO) mice. Each model was compared with the corresponding wild type (Wt). Five craniofacial distances were analysed: craniofacial length, upper face height, mandibular anterior height, mandibular ramus length, and mandibular corpus length. In addition, upper and lower incisor lengths and four angular relationships, nasal bone with cranial base, maxillary plane with cranial base, mandibular plane with cranial base, and the angle of the mandible, were determined. Data were analysed by one-way ANOVA. Craniofacial length, upper face height and mandibular corpus length were significantly increased in the giant mice and significantly reduced in the dwarf mice. Mandibular anterior height and mandibular ramus length were significantly affected in the dwarf-KO mice but not in the giant mice. The length of both the upper and lower incisors was significantly increased and reduced in the giant and dwarf-KO mice, respectively. In addition, the angle of the mandible was significantly increased in the giant mice and significantly reduced in the dwarf mice. It is concluded that GH plays a major role in the growth and development of the craniofacial complex by directly and indirectly modulating the size and the angular relationships of the craniofacial structures, including the incisor teeth.

The Dickkopf (Dkk) family and Mmp9 are important for apoptosis and a number of other developmental processes. However, little is known about their roles in the development of cranial base, which is an important structure for coordinated development and growth of the craniofacial skeletons. In order to establish whether and in what way these genes are involved in cranial base development, we examined their expression patterns and cell apoptosis. Dkk1 was first seen in the perichondral mesenchyme in restricted domains from E14, and later in the migrating mesenchymal cells within the cartilage. Thereafter, it was widespread throughout the bones of the cranial base. The expression was downregulated in postnatal stages. Dkk2 was localized in the perichondral mesenchyme outlining the anterior cranial base in embryogenesis. Dkk3 was mainly detected in the occipital-vertebral joint at E13 and E14. Mmp9 transcripts were clustered in the inner layer of perichondral mesenchyme, juxtaposed with the terminally differentiated hypertrophic chondrocytes from E14. Later Mmp9-expressing cells were found at the sites of chondrocyte apoptosis. This was particularly clear at the distal ends of the synchondroses. These data indicate that Mmp9 regulates skeletogenesis in cranial base in a manner that is largely similar to that of the appendicular skeletons. Expression of Dkks suggests other roles that remain to be defined.

The cranial base is of crucial importance in integrated craniofacial development. As distinct from facial bones, it is formed through endochondral ossification. The posterior and anterior cranial bases are derived from distinct embryologic origins and grow independently--the anterior cranial base solely from the neural crest, the posterior cranial base from the paraxial mesoderm. The anterior cranial base has more prolonged and active growth and exerts more influence on facial growth than does the posterior cranial base. Cranial base angulation is a unique feature in modern human beings. Cranial base anomalies have been identified in many genetic and developmental disorders. The molecular basis of cranial base development and growth is being clarified. In this review, these aspects of cranial base are discussed in detail, with a focus on developmental features, roles in craniofacial growth, anomalies, and the genetic basis of development.

The upper airway controls the mechanisms of breathing, swallowing, and vocalization. Information on its normal ontogenetic associations is therefore crucial for understanding human speech evolution as well as the developmental etiology of speech abnormalities. Of particular interest to evolutionary morphologists is the proposed structural association between the upper airway and the cranial base. The present study aims to elucidate whether cranial base angulation is linked to growth of the upper airway during human fetal life. Forty postmortem human fetuses ranging from 10 to 29 weeks of gestation were imaged with high-resolution magnetic resonance imaging. Measurements of basicranial angle, hyoid depth, hormion height, and pharyngeal area were taken from sagittal images. Results show a significant correlation between the internal and external basicranial angles but the correlation between relative hyoid depth and internal cranial base angle was not significant. Findings show a significant correlation between increases in the size of the oropharynx relative to the nasopharynx and increases in the internal cranial base angle (retroflexion). These findings give limited support (rrank=0.46; P<0.01) for the hypothesis that restructuring of the upper airway underlies basicranial retroflexion during prenatal life., (Copyright (c) 2005 Wiley-Liss, Inc.)

This article describes an extremely rare case, encountered in the anatomy laboratory, of a skull base found to have duplication of both occipital condyles. In addition, this specimen was noted to have a large bony excrescence near the basion, a small third occipital condyle, a left paracondylar process, elongation of the right styloid process, and a bony septation of both hypoglossal canals. The embryology and clinical implications are discussed., (Copyright 2005 Wiley-Liss, Inc.)

We report a new cephalometric method for profile analysis, which uses strictly exobasicranial landmarks: 13 anatomic points, 9 bone points and 4 skin points. The analysis is based on phylogenetic, ontogenetic, anatomic and biomechanical data. Phylogenetic analysis reveals that the occipital plate belongs more to the cranial vault than the base of the skull. Embryology shows that on the midline the facial skull base ends at the spheno-occipital suture and that the overall skull base ends at the basion. The pre-maxillary fuses rapidly to the maxillary, while the pterygoid processes, which belong to the face and not the skull base, fusion very rapidly to the skull base. Revisiting the anatomy of the facial skull base shows that it is prolonged posteriorly medially to meast the synostosic creast and latterally to the glenoid fossae. Further anatomic analysis shows that the dentate and muscular part of the superior level of the facial mass correspond to equivalent parts of the inferior mandibular level. The biomechanical analysis reveals that the anterior pillar passes through the pre-maxillary, ending on the supra-orbital border and the glabella and as such belongs to the face. The posterior pillar follows the pterygoid process ending in the sphenoid. The glabella and these two pillars are taken into account in this new analysis technique.

An appreciation of ontogenetic changes to the cranial base is important for understanding the evolution of modern human skull form. Using geometric morphometric techniques, this study explores midline shape variations of the basicranium and midface during human prenatal ontogeny. In particular, the analysis sets out to explore shape variations associated with endochondral ossification and to reassess shape variations previously observed on the basis of angular measures.Fifty-four formalin-preserved human fetuses were imaged using high-resolution MRI. Coordinates for 10 landmarks defining the midline basicranium and midface were acquired and areas of ossification in the midline basioccipital, basisphenoid, and presphenoid cartilages were measured as percentages of overall cranial base area. The results show shape variations with increasing fetal size that are consistent with cranial base retroflexion, anterior facial projection and dorsal facial rotation. These growth variations are centered on the midsphenoid area and are associated with disproportionate variations of sphenoid height and length. Small but significant correlations were observed between ossification of the presphenoid cartilage and components of shape that described, among other variations, sphenoid shortening. While ossification cannot be directly linked with the shape variations observed, it seems likely that bone formation plays a role in modulating the influence of other factors on the fetal cranial base., (Copyright 2003 Wiley-Liss, Inc.)

Objectives: To describe the development of the osseous field enclosing the cerebellum and part of the brain stem (the neuro-osteological cerebellar field) in Down syndrome, and compare the development with normal developmental standard of the field., Design: Radiographic, cephalometric and histologic examination of 58 legally or spontaneously aborted Down syndrome prenatal human fetuses; crown-rump length of 80-255 mm and approximate gestational age from 13 to 26 weeks., Results: The growth of the Down syndrome cerebellar field is smaller in the sagittal and vertical directions than in normal fetuses., Conclusion: In the present study the pathological development of the cerebellar field was described in a genotypic sample. In combining normal and pathological development of neural and osseous tissues a better understanding of the genotype/phenotype interactions is attainable and fields of common gene expression maybe defined.

The basicranium is the keystone of the primate skull, and understanding its morphological interdependence on surrounding soft-tissue structures, such as the brain, can reveal important mechanisms of skull development and evolution. In particular, several extensive investigations have shown that, across extant adult primates, the degree of basicranial flexion and petrous orientation are closely linked to increases in brain size relative to cranial base length. The aim of this study was to determine if an equivalent link exists during prenatal life. Specific hypotheses tested included the idea that increases in relative endocranial size (IRE5), relative infratentorial size (RIE), and differential encephalization (IDE) determine the degree of basicranial flexion and coronal petrous reorientation during non-hominoid primate fetal development. Cross-sectional fetal samples of Alouatta caraya (n=17) and Macaca nemestrina (n=24) were imaged using high-resolution magnetic resonance imaging (hrMRI). Cranial base angles (CBA), petrous orientations (IPA), base lengths, and endocranial volumes were measured from the images. Findings for both samples showed retroflexion, or flattening, of the cranial base and coronal petrous reorientation as well as considerable increases in absolute and relative brain sizes. Although significant correlations of both IRE5 and RIE were observed against CBA and IPA, the correlation with CBA was in the opposite direction to that predicted by the hypotheses. Variations of IDE were not significantly correlated with either angle. Correlations of IPA with IRE5 and RIE appeared to support the hypotheses. However, partial coefficients computed for all significant correlations indicated that changes to the fetal non-hominoid primate cranial base were more closely related to increases in body size than the hypothesized influence of relative brain enlargement. These findings were discussed together with those from a previous study of modern human fetuses.

The sphenoid bone represents a complex structure in terms of anatomy and embryology. Indeed, it is formed by the fusion of different primordia whose embryonic origins are different. In mammals, it is possible to distinguish two components of this bone: the orbitosphenoid and the basi-post-sphenoid derive from the cephalic mesoderm whereas the alisphenoid and the basi-pre-sphenoid are from neural crest cell origin. The genetic control of the development of these two components is different further increasing the heterogeneity of these components. The sphenoid bone has been linked with several developmental diseases: chordomas, tumors arising from notochordal remnants; persistence of the craniopharyngeal canal may result in the occurrence of trans-sphenoidal encephaloceles.

Objectives: To describe the pre-natal development of the bones that enclose the cerebellum and part of the brain stem (the neuro-osteological cerebellar field) in the mid-sagittal plane., Design: Radiographic, cephalometric and histologic examination of normal pre-natal human fetuses; 50 normal fetuses, with crown-rump length of 18-227 mm and approximate gestational age from 6 to 26 weeks., Results: The cerebellar field expressed extensive growth during development both sagittally and vertically. Because of changes in shape, the field was displaced in an anterio-caudal direction., Conclusion: In the present study we recorded normal measurements of size, shape and position of the cerebellar field. These standards can be used as references in skeletal analysis of cases with cranial abnormalities and cerebellar malformations.

The aim of this study was a continuous and rather exhaustive description of the embryological development of the lateral sellar compartment. The histological sections of 39 embryos and fetuses were studied, and represent the first six months of intra-uterine life. The embryological period showed the organization of the content of the compartment. The medial and lateral walls appeared during the 15th week of amenorrhoea, and did not modify later. The medial wall was constituted in its rostral part by the hypophyseal lodge and in its caudal part by the periosteum of the sphenoid bone. Two layers formed the lateral wall: the superficial layer was an expansion of the dura mater that surrounded the oculomotor nerves along their course to the superior orbital fissure; the deep layer was weaker, and surrounded and joined the nerves together. The results of this study advocate the evolution of the nomenclature of this region, as the term "inter-periosto-dural space" would better reflect the real pattern of the lateral sellar compartment. Furthermore, the presence of a communication between the two lateral sellar compartments has led to a discussion of the previous hypothesis about the development of the lateral sellar compartment. The venous network was located on both the medial and lateral sides of the internal carotid artery, but expanded in the lateral wall of the lateral sellar compartment. That is of interest to surgeons and radiologists because it could explain some hemorrhagic complications.

This study investigates whether macaques and humans possess a common pattern of relative growth during the fetal period. The fetal samples consist of 16 male pigtailed macaques (mean age, 20.5 gestational weeks) and 17 humans (9 males and 8 females; mean age, 29.5 gestational weeks). For each individual, three-dimensional coordinates of 18 landmarks on the skull were collected from three-dimensional computed tomographic (CT) reconstructed images and two-dimensional CT axial slices. Early and late groups were created from the human (early mean age, 24 weeks, N = 8; late mean age, 34 weeks, N = 9) and macaque samples (early mean age, 17.7 weeks, N = 7; late mean age, 23 weeks, N = 9). Inter- and intraspecific comparisons were made between the early and late groups. To determine if macaques and humans share a common fetal pattern of relative growth, human change in shape estimated from a comparison of early and late groups was compared to the pattern estimated between early and late macaque groups. Euclidean distance matrix analysis was used in all comparisons. Intraspecific comparisons indicate that the growing fetal skull displays the greatest amount of change along mediolateral dimensions. Changes during human growth are primarily localized to the basicranium and palate, while macaques experience localized change in the midface. Interspecific comparisons indicate that the two primate species do not share a common pattern of relative growth, and the macaque pattern is characterized by increased midfacial growth relative to humans. Our results suggest that morphological differences in the craniofacial skeleton of these species are in part established by differences in fetal growth patterns., (Copyright 2003 Wiley-Liss, Inc.)

Surgical pathology of the pediatric cranial base is uncommon, but in affected children, traditional operative techniques and management philosophies predominate. While the creation of multidisciplinary skull base teams synergistically pools the talents of individual specialties, a better understanding of the developmental anatomy of the cranial base becomes essential in order for such teams to safely implement these approaches in children. The extant neurosurgical literature lacks a comprehensive review of this anatomy. This report discusses the developmental anatomy and embryology of the cranial base within the context of specific surgical approaches. Detailed development of the calvaria, midface skeleton and orbit is excluded., (Copyright 2003 S. Karger AG, Basel)

Through a revision of the classical anatomy of the exocranial skull base, the authors present of a new exobasicranial plan in cephalometry, the Nasion-Glenion (or Porion plane). The median part of the base devoted to ventilation goes from the Nasion to the spheno-occipital synchondrosis, joining two essentially cartilaginous sites. The lateral parts, with manducatory functions, extend from supra-orbital rim to glenoid fossa and are mainly membranous. Pterygoid processes belong to the facial squeleton. Dental and growth axes are projected on the new exobasicranial base. Facial structures are analyzed in four planes, perpendicular to Francfort plane (facial cutaneous plane, premaxillary plane, postmaxillary plane, craniocervical plane).

Objective: To construct nomograms for cranial base parameters of normal fetuses., Study Design: A cross-sectional study of 386 normal singleton fetuses at 14-40 weeks' gestation. Measurements of the length and width of the sphenoid bone anteriorly and the otic cartilage posteriorly and of the angles between the ridges were obtained., Results: Nomograms of the length and width of sphenoid ridge and otic cartilage, and of the angles in the cranial fossae are presented. A linear growth function was observed between cranial base measurements (sphenoid ridge length, otic cartilage length, cranial base angles) and gestational age, femur length and biparietal diameter., Conclusion: Measurements of the length of cranial base ridges and the angles between them can be obtained easily in the second and third trimesters and might prove useful in the evaluation of pregnancies at high risk for associated fetal abnormalities.