Endocranial Surface Research Articles

Response to Comment on “The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)”

The comment by DeSilva challenges our suggestion that brain growth of the El Sidrón J1 Neandertal was still incomplete at 7.7 years of age. Evidence suggests that endocranial volume is likely to represent less than 90% adult size at El Sidrón as well as Neandertal male plus Krapina samples, in line with further evidence from endocranial surface histology and dural sinus groove size.

Neurocranial anatomy of the petalichthyid placoderm Shearsbyaspis oepiki Young revealed by X-ray computed microtomography.

Stem‐group gnathostomes reveal the sequence of character acquisition in the origin of modern jawed vertebrates. The petalichthyids are placoderm‐grade stem‐group gnathostomes known from both isolated skeletal material and rarer articulated specimens of one genus. They are of particular interest because of anatomical resemblances with osteostracans, the jawless sister group of jawed vertebrates. Because of this, they have become central to debates on the relationships of placoderms and the primitive cranial architecture of gnathostomes. However, among petalichthyids, only the braincase of Macropetalichthys has been studied in detail, and the diversity of neurocranial morphology in this group remains poorly documented. Using X‐ray computed microtomography, we investigated the endocranial morphology of Shearsbyaspis oepiki Young, a three‐dimensionally preserved petalichthyid from the Early Devonian of Taemas‐Wee Jasper, Australia. We generated virtual reconstructions of the external endocranial surfaces, orbital walls and cranial endocavity, including canals for major nerves and blood vessels. The neurocranium of Shearsbyaspis resembles that of Macropetalichthys, particularly in the morphology of the brain cavity, nerves and blood vessels. Many characters, including the morphology of the pituitary vein canal and the course of the trigeminal nerve, recall the morphology of osteostracans. Additionally, the presence of a parasphenoid in Shearsbyaspis (previously not known with confidence outside of arthrodires and osteichthyans) raises some questions about current proposals of placoderm paraphyly. Our detailed description of this specimen adds to the known morphological diversity of petalichthyids, and invites critical reappraisal of the phylogenetic relationships of placoderms.

Viral infections, neonatal mortality and the mystery of the Athenian Agora: An interview with Professor of Anthropology Maria Liston.

Although excavated almost 80 years ago, the infants' ‘bone well’ of the Athenian Agora in Athens, Greece and its contents were never thoroughly evaluated and published, until only recently, when a re-analysis of the whole excavation findings was performed. The well dates back to the third quarter of the 2nd century BC and contained at least 449 infants. The project, which explored the causes of neonatal mortality, found that one-third of infants' deaths were attributed to neonatal meningitis, based on the presence of bone disposition on the endocranial surface of the studied skulls. Despite the non-specific differential diagnostic approach of this pathophysiological finding in neonates, the determination of the causes of neonatal mortality in the Athenian Agora is really an impressive scientific attempt and can be a valuable lesson to all neonatal and peadiatric health professionals. According to Professor Maria Liston, Associate Professor of Anthropology at the University of Waterloo in Canada, who was the principal investigator of the skeletons from the infants' ‘bone well’ of the Athenian Agora, neonatal meningitis was the most frequently detected cause of neonatal mortality. Viral diseases unquestionably contributed to neonatal mortality, she adds and highlights that further research is required in collaboration with physicians for the better understanding and interpretation of various archaeological findings related to neonatal mortality. In the context of the 3rd Workshop on Paediatric Virology, which will be held in October 7th, 2017 in Athens, Greece, Professor Liston will reveal the role of neonatal and paediatric viral infections in the Hellenic antiquity.

Excessive dietary intake of vitamin A reduces skull bone thickness in mice.

Calvarial thinning and skull bone defects have been reported in infants with hypervitaminosis A. These findings have also been described in humans, mice and zebrafish with loss-of-function mutations in the enzyme CYP26B1 that degrades retinoic acid (RA), the active metabolite of vitamin A, indicating that these effects are indeed caused by too high levels of vitamin A and that evolutionary conserved mechanisms are involved. To explore these mechanisms, we have fed young mice excessive doses of vitamin A for one week and then analyzed the skull bones using micro computed tomography, histomorphometry, histology and immunohistochemistry. In addition, we have examined the effect of RA on gene expression in osteoblasts in vitro. Compared to a standard diet, a high dietary intake of vitamin A resulted in a rapid and significant reduction in calvarial bone density and suture diastasis. The bone formation rate was almost halved. There was also increased staining of tartrate resistant acid phosphatase in osteocytes and an increased perilacunar matrix area, indicating osteocytic osteolysis. Consistent with this, RA induced genes associated with bone degradation in osteoblasts in vitro. Moreover, and in contrast to other known bone resorption stimulators, vitamin A induced osteoclastic bone resorption on the endocranial surfaces.

Automatic extraction of endocranial surfaces from CT images of crania.

The authors present a method for extracting polygon data of endocranial surfaces from CT images of human crania. Based on the fact that the endocast is the largest empty space in the crania, we automate a procedure for endocast extraction by integrating several image processing techniques. Given CT images of human crania, the proposed method extracts endocranial surfaces by the following three steps. The first step is binarization in order to fill void structures, such as diploic space and cracks in the skull. We use a void detection method based on mathematical morphology. The second step is watershed-based segmentation of the endocranial part from the binary image of the CT image. Here, we introduce an automatic initial seed assignment method for the endocranial region using the distance field of the binary image. The final step is partial polygonization of the CT images using the segmentation results as mask images. The resulting polygons represent only the endocranial part, and the closed manifold surfaces are computed even though the endocast is not isolated in the cranium. Since only the isovalue threshold and the size of void structures are required, the procedure is not dependent on the experience of the user. The present paper also demonstrates that the proposed method can extract polygon data of endocasts from CT images of various crania.

Age-related changes of sulcal imprints on the endocranium in the Japanese macaque (Macaca fuscata).

The degree of expression of sulcal patterns on endocasts of nonhuman primates has been shown to depend primarily on species (brain size) and age of the individual. It has been suggested that brain details on endocasts are reproduced better in juvenile than adult primates. Here, we investigated age-related changes in the imprint of the major sulci on the endocranium of Japanese macaques (Macaca fuscata) from the juvenile period to adulthood. Using CT scans of 25 (12 males, 13 females) cranial specimens from macaques, we generated virtual endocasts to assess imprints of the seven main sulci on the endocranial surface. Expression of each sulcal imprint was evaluated by imprint score method. The degree of expression of sulcal imprints differed between sulci. Arcuate, superior temporal, and principal sulci were well defined, whereas lunate and intraparietal sulci were poorly represented. Sulcal imprints showed significant age-related changes in Japanese macaques from juvenile to elderly. Sulcal imprints showed a slight decrease in degree of expression from the juvenile period (2-4 years) to adolescence (4-6 years), and then remained unchanged until mid-adulthood (15-16 years). The degree of expression of the sulcal imprints significantly decreased from mid-adulthood to old age (>20 years). The degree of expression of the sulcal imprints (relief forms) in inner table bone surface (endocranium) reveals significant age-related decreases in adults. The great decrease starts at around 20 years of age. The endocranial volume showed a significant age-related increase, and thus, it is suggested that the endocranial surface in macaques may be resorbed with advancing age.

Miniscrew-assisted slow expansion of mature rabbit sutures.

In this study, we experimentally evaluated whether complex, mature sutures can be separated using skeletal anchorage and light, continuous forces. Twelve adult, 8- to 9-month-old female New Zealand white rabbits were randomly assigned to 1 control group and 2 experimental groups. Open-coil nickel-titanium springs delivered constant forces of 100g across the sagittal suture to miniscrew implants placed bilaterally in the frontal bone. Sutural separation was measured biweekly. Separation was also measured with microcomputed tomography. Bone formation (mineral apposition) was measured with fluorescent labels. Qualitative histologic analyses of the suture tissues were performed using hematoxylin and eosin staining; osteoclasts were evaluated with tartrate resistant acid phosphatase staining. All 24 miniscrew implants remained stable throughout the experiment. There was no statistically significant sutural separation in the control group. In the experimental groups, sutural separation was significant (P<0.05) at all time points after the initial records were taken. The rate of separation was linear during the first 42days. There were moderate correlations (R=0.59-0.89; P<0.05) between miniscrew implant separation and bone marker separation. Mineral apposition rate, which was not measureable in the control group, was significant in the experimental group. The mineral apposition rate was greater between 14 and 28days than between 28 and 38days, and it was greater on the ectocranial than on the endocranial surface. Based on the microcomputed tomography analysis, 3-dimensional sutural volume of the experimental group increased significantly (P=0.02), but surface area did not (P=0.26). It is possible to separate the sagittal suture of mature rabbits. Sutural separation is limited, indicating involvement of other articulations.

Cranial Morphology of the Late Oligocene Patagonian Notohippid Rhynchippus equinus Ameghino, 1897 (Mammalia, Notoungulata) with Emphases in Basicranial and Auditory Region.

“Notohippidae” is a probably paraphyletic family of medium sized notoungulates with complete dentition and early tendency to hypsodonty. They have been recorded from early Eocene to early Miocene, being particularly diverse by the late Oligocene. Although Rhynchippus equinus Ameghino is one of the most frequent notohippids in the fossil record, there are scarce data about cranial osteology other than the classical descriptions which date back to the early last century. In this context, we describe the exceptionally preserved specimen MPEF PV 695 (based on CT scanning technique and 3D reconstruction) with the aim of improving our knowledge of the species, especially regarding auditory region (petrosal, tympanic and surrounding elements), sphenoidal and occipital complexes. Besides a modular description of the whole skull, osteological correlates identified on the basicranium are used to infer some soft-tissue elements, especially those associated with vessels that supply the head, mainly intracranially. One of the most informative elements was the petrosal bone, whose general morphology matches that expected for a toxodont. The endocranial surface, together with the surrounding parietal, basisphenoid, occipital, and squamosal, enabled us to propose the location and communication of main venous sinuses of the lateral head wall (temporal, inferior and sigmoid sinuses), whereas the tympanic aspect and the identification of a posterior carotid artery canal provided strong evidence in support of an intratympanic course of the internal carotid artery, a controversial issue among notoungulates. Regarding the arrangement of tympanic and paratympanic spaces, the preservation of the specimen allowed us to appreciate the three connected spaces that constitute a heavily pneumatized middle ear; the epitympanic sinus, the tympanic cavity itself, and the ventral expansion of the tympanic cavity through the notably inflated bullae. We hope this study stimulates further inquires and provides potentially informative data for future research involving other representatives of the order.

Frontal cranial modeling using endocranial resorbable plate fixation in 27 consecutive plagiocephaly and trigonocephaly patients.

Premature ossification of coronal and metopic sutures is treated by fronto-orbital remodeling. Such operations require stable fixation of the reshaped cranial bones. Currently, biodegradable plating systems are used to provide sufficient stability over the time that takes for the osteotomies to ossify. Plates that are placed traditionally on the outer surface of the cranium are often palpable and even visible through the thin overlying skin, compromising the cosmetic results of these operations. Improved aesthetics could be achieved by placing the plates endocranially. This study aimed to evaluate endocranial resorbable plate fixation and its clinical and radiographic results in frontal remodeling cranioplasty for plagiocephaly and trigonocephaly patients with follow-up sufficiently long for the plates to have been completely resorbed. A poly(lactide-co-glycolide) (PLGA) resorbable plating system was used on the inner aspect of frontal bone in 27 patients treated for coronal and metopic craniosynostoses. The outcome was evaluated at follow-up visits. The mean follow-up was 79.2months. Three patients had complications that required reoperations. None of these complications were related to the endocranial location of the plates. There were no problems with ossification of the osteotomy sites. All but one patient's outcome was judged as good or excellent. Placement of resorbable fixation on the endocranial surface of the calvarial bones is safe, stable, and results in satisfactory aesthetics without interfering with the ossification of the cranial bones.

Improved reliability for fractal dimension calculation of the vascular imprints on the cranial vault mapped with topographical correction.

We presented a novel approach to studies of the vascular grooves located on the inner surface of the cranial vault. A three-dimensional vision system that acquired the endocranial surface topography was used for this purpose. The acquired data were used to generate images showing the branching pattern of the middle meningeal artery. Fractal dimension was used to characterize and analyze branching pattern complexity. We discussed the usefulness of the latter method and indicated difficulties and potential errors connected to the fractal dimension application. The technique introduced for recording traits of the object surface appears to be helpful in anatomical study of morphological variation of dural vascularization. It may also be applicable in paleoneurological research based on analysis of the cranial remnants. Fractal dimension should be used carefully as a method sensitive to many aspects of data acquisition and processing.

Unusual spinal tuberculosis in an Avar Age skeleton (Csongrád-Felgyő, Ürmös-tanya, Hungary): A morphological and biomolecular study

The paleopathological analysis of a well-preserved young adult female skeleton from the AD 7-8th century (Avar Age) in Hungary revealed multiple lytic lesions in all of the thoracic and lumbar vertebral bodies. The lesions were characterized by smooth marginal zones and space-occupying mass appearance. The considerable loss of spongy bone in the thoracolumbar vertebrae resulted in angular deformity and fusion, characteristic of the healing stage of TB. Osteolytic lesions were also observed on the vertebral processes, ribs and sternum. On the endocranial surface, abnormal blood vessel impressions were revealed, indicating some kind of meningitis. The X-ray and CT analysis of the affected bones detected abnormal structures and cystic zones of destruction. The lesions were however not always bordered by areas of increased density, which is typical in cystic TB. Vertebral remains were also subjected to biomolecular analysis in two different laboratories, which attested the presence of Mycobacterium tuberculosis complex (MTBC) DNA and supported the paleopathological diagnosis of TB. Spoligotyping analysis confirmed the presence of MTBC DNA and more specifically an infection caused by bacteria belonging to the M. tuberculosis lineage. This case study provides new data for the paleoepidemiology of TB in this geographical area and historical period, and draws attention to the great variability of TB lesions in the human skeleton.

7000 year-old tuberculosis cases from Hungary – Osteological and biomolecular evidence

This study derives from the macroscopic analysis of a Late Neolithic population from Hungary. Remains were recovered from a tell settlement at Hódmezővásárhely-Gorzsa from graves within the settlement as well as pits, ditches, houses and as stray finds. One of the most important discoveries from these remains was evidence of tuberculosis. Pathological analysis of the seventy-one individuals revealed numerous cases of infections and non-specific stress indicators on juveniles and adults, metabolic diseases on juveniles, and evidence of trauma and mechanical changes on adults. Several cases showed potential signs of tuberculosis and further analyses were undertaken, including biomolecular studies. The five individuals were all very young adults and included a striking case of Hypertrophic Pulmonary Osteopathy (HPO) with rib changes, one case with resorptive lesions on the vertebrae, two cases with hypervascularisation on the vertebrae and periosteal remodelling on the ribs, and one case with abnormal blood vessel impressions and a possible lesion on the endocranial surface of the skull. The initial macroscopic diagnosis of these five cases was confirmed by lipid biomarker analyses, and three of them were corroborated by DNA analysis. At present, these 7000-year-old individuals are among the oldest palaeopathological and palaeomicrobiological cases of tuberculosis worldwide.

Pulverized human skull in pharmacological preparations: Possible evidence from the “martyrs of Otranto” (southern Italy, 1480)

Ethnopharmacological relevanceEver since the Late Medieval Ages historico-medical literature has attested the use of cranium humanun as an ingredient in pharmacological preparations for the treatment of epilepsy. Some authors suggest the use of pulverized bone obtained from individuals who died a violent death and were not buried. Materials and methodsThe skeletal remains of hundreds of male inhabitants from Otranto, killed by the Ottomans in a mass execution on 14 August, 1480, are preserved in the Chapel of Martyrs in Otranto Cathedral (Apulia, southern Italy). The so-called “martyrs of Otranto” were beatified in 1771 and canonized by Pope Francis on 12 May, 2013. A cranial vault with 16 holes of different sizes, with regular rounded shape, was noticed among the skeletal remains, symmetrically arranged behind five large rectangular windows. Eight of the 16 holes, which exposed the diploe without reaching the endocranial surface, are incomplete perforations, while 8 holes are complete perforations; no evidence of bone reaction is visible. ResultsThe lesions are the result of a multiple trepanation performed by using an instrument equipped with a large rounded tip. This tool could not produce bone discs, but only bone powder. It is impossible to establish with certainty the reasons for these multiple trepanations, but several hypotheses can be advanced, ranging from experimental surgery to a procedure designed to obtain relics. However, saint bones are very likely to have been regarded as having medicinal properties. As a matter of fact the martyrs of Otranto died a violent death and were not buried, and the pulverized bone obtained from their skulls might have been considered a particularly powerful ingredient for pharmacological preparations, as attested in the historico-medical literature. ConclusionsThe skull of Otranto might represent a unique evidence of multiple trepanations carried out to obtain bone powder as ingredient for therapeutic preparations.

On the Cranial Osteology of the African Palm Civet,Nandinia binotata(Gray, 1830) (Mammalia, Carnivora, Feliformia)

The external and endocranial surfaces of the skull of the African palm civet, Nandinia binotata (Gray, 1830), are described and illustrated in detail based on 30 specimens (from Carnegie Museum of Natural History and American Museum of Natural History). With the inclusion of a newborn and six juveniles with deciduous dentitions, a reasonable ontogenetic series is represented. The bone-by-bone descriptions are primarily based on the condition in an adult female and the newborn with consideration of variation across the sample. The principal cranial foramina are treated in a glossary, and the hyoid apparatus and larynx are described from a single specimen. The sample exhibits a remarkable degree of variability in cranial features that are often used as different states of characters in phylogenetic analysis (e.g., number and position of palatal foramina, the orbital mosaic, and composition of the lacrimal foramen).Nandinia binotata, the only taxon in the Nandiniidae, has been identified as the most basal extant feliform in recent phylogenetic analyses of both molecular and morphological data. It has long been recognized that its ear region with its uninflated auditory bulla exhibits a primitive level of organization. To assess the primitive nature of the skull of N. binotata, comparisons are made with three extant carnivorans, the felid Felis catus Linnaeus, 1758, the viverrid Genetta genetta (Linnaeus, 1758), and the canid Canis lupus Linnaeus, 1758. Of the three, N. binotata shares numerous resemblances across the skull with G. genetta, which accounts for its historical inclusion in the Viverridae. Whereas aspects of the ear region of N. binotata are clearly unique among extant carnivorans, the rest of its skull is not similarly so.

Endocranial Lesions

Numerous intracranial soft tissue and vascular structures are intimately related to the endocranial surface of the central skull base, including the pituitary gland, the pachymeninges, and multiple cranial nerves. These structures can give rise to pathologies that create imaging abnormalities along the bony surface of the skull base or result in gross changes of the underlying bone: hyperostosis, scalloping, permeation, erosion, or destruction. Large lesions with frank invasion may be difficult to differentiate from intrinsic bone lesions. This article reviews a variety of endocranial lesions affecting the central skull base, including the giant or invasive pituitary macroadenoma and skull base meningioma, and highlights the imaging features for a practical approach to their diagnosis.

Skull sutures: Changing morphology during preadolescent growth and its implications in forensic identification

Forensic identification of juvenile skulls is a problem area. Although the skull suture patterns have been suggested for use in individualizing human remains by comparing antemortem and postmortem radiographs, the age at which such patterns stabilize and can be useful for identification had been indicated as 7 years. Subsequent researchers have also concurred that antemortem and postmortem radiographs taken after the 7th year would be sufficient to meet the Daubert standard criteria for identifying skulls using radiographs. The suggestions regarding the lower age limit for stabilization of suture patterns have not been verified so far. In this research, the patterns of the sutures in the ectocranial and endocranial surfaces of the lambdoid region in 22 juvenile skulls (age range 1–10 years) and 100 adult skulls (age range 17–70 years) were studied for the relative incidence of different types of suture patterns. The radiographic recordings of the suture patterns in the juvenile skulls were also compared with the patterns seen in the ectocranial and endocranial surfaces. The findings of this study support the proposition that the suture patterns are plastic during the juvenile stage and that they undergo significant remodeling during growth into adulthood. Indicating the possibility of growth related alterations in the sutural morphology, the onset of adulthood is suggested as the age for stabilization of suture patterns in the context of prescribing standards for such criteria as those relating to Daubert.

Quantifying patterns of endocranial heat distribution: Brain geometry and thermoregulation

The mechanisms involved in brain thermoregulation are still poorly known, and many disagreements still exist concerning the selective cooling capacity of the brain volume. This issue has also been discussed in human evolution and paleoneurology, speculating on possible changes associated with hominid encephalization. Although the vascular system is supposed to be the main component responsible for thermoregulation, brain geometry also plays an important role in the pattern of heat distribution. In fossils, the only neuroanatomical evidence available for quantitative analyses is the endocranial form, molded by the brain morphology. Here, we present a quantitative method based on numerical simulations to quantify and localize variation in heat dissipation patterns associated with endocranial morphological changes, presenting a case-study on modern humans and chimpanzees. Thermic maps provide a graphic tool to visualize heat loading on the endocranial surface. The distribution of the values (thermic spectrum) supplies a quantification which can help describe and compare the patterns of heat distribution within and between groups. Absolute values are largely influenced by size differences. Normalized values suggest further differences associated with brain shape. Simulation and numerical modeling are useful to provide a descriptive and quantitative approach to endocranial thermoregulation, supplying a quantitative tool to investigate ontogenic and phylogenetic changes. This is particularly relevant in paleoneurology, considering the large shape and size differences described for fossil hominid brains.

Comparison of the endocranial ontogenies between chimpanzees and bonobos via temporal regression and spatiotemporal registration

This paper aims at quantifying ontogenetic differences between bonobo ( Pan paniscus) and chimpanzee ( Pan troglodytes) endocrania, using dental development as a timeline. We utilize a methodology based on smooth and invertible deformations combined with a metric of “currents” that defines a distance between endocranial surfaces and does not rely on correspondence between landmarks. This allows us to perform a temporal surface regression that estimates typical endocranial ontogenetic trajectories separately for bonobos and chimpanzees. We highlight non-linear patterns of endocranial ontogenetic change and significant differences between species at local anatomical levels rather than considering the endocranium as a uniform entity. A spatiotemporal registration permits the quantification of inter-species differences decomposed into a morphological deformation (accounting for size and shape differences independently of age) and a time warp (accounting for changes in the dynamics of development). Our statistical simulations suggest that patterns of endocranial volume (EV) increase may differ significantly between bonobos and chimpanzees, with an earlier phase of a relatively rapid increase (preferentially at some endocranial subdivisions) in the former and a much later phase of relatively rapid increase in the latter. As a consequence, the chimpanzee endocranium appears to reach its adult size later. Moreover, the time warp indicates that juvenile bonobos develop much slower than juvenile chimpanzees, suggesting that inter-specific ontogenetic shifts do not only concern EV increase, but also the rate of shape changes over time. Our method provides, for the first time, a quantitative estimation of inter-specific ontogenetic shifts that appear to differentiate non-linearly.

Surgery in the early middle ages: Evidence of cauterisation from Pisa

ARCHEOLOGIC EXCAVATIONS carried out in the famous Cathedral Square of Pisa brought to light a multiple ground grave dating to the early Middle Ages (8th–10th Centuries AD). The well preserved skull of an adult female aged about 30 years revealed some form of ‘‘surgical’’ intervention. In the central part of the frontal bone, 4 cm from the bregma, a 20 3 17 mm elliptical lesion limited by a shallow 1-mm thick groove is easily visible (Fig, A); the surface of the lesion appears to be finely cribrose with minute bone crests radially disposed around a more marked central crest (Fig, B). The endocranial surface is intact. The lesion appears to be the result of an inflammatory process of the soft tissues and the periostium that involved the underlying skull vault. The central position on the sagittal axis and the size and regular shape of the lesion excludes some disease as the cause, suggesting that this lesion is an artifact, in particular the result of cauterization, a surgical practice attested since the time of Hippocrates. The last sentence of his Aphorisms, which had a large circulation in the Antiquity and in the Middle Ages, reads: ‘‘What drugs will not cure, the knife will; what the knife will not cure, the cautery will; what the cautery will not cure must be considered incurable.’’ The Roman iron cautery, ferrum candens, was heated and used extensively in Roman medicine

Bruxism and Temporal Bone Hypermobility in Patients with Multiple Sclerosis

In this study, the authors investigated the link between jaw clenching/bruxism and temporal bone movement associated with multiple sclerosis (MS). Twenty-one subjects participated in this study (10 patients with MS and 11 controls). To quantify the change in intracranial dimension between the endocranial surfaces of the temporal bones during jaw clenching, an ultrasonic pulsed phase locked loop (PPLL) device was used. A sustained jaw clenching force of 100 lbs was used to measure the mean change in acoustic pathlength (ΔL) as the measure of intracranial distance. In the control subjects the mean ΔL was 0.27 mm±0.24. In subjects with MS the mean ΔL was 1.71 mm±1.18 (p<0.001). The increase in magnitude of bi-temporal bone intracranial expansion was approximately six times greater in subjects with MS compared to controls. Therefore, jaw clenching/bruxism is associated with more marked displacement of the temporal bones and expansion of the cranial cavity in patients with MS than in control subjects.