Etiopathogenesis of hyperostosis frontalis interna: A mystery still

Space invaders: Reassessing the histology of hyperostosis frontalis interna

Hyperostosis frontalis interna (HFI) is a human skeletal lesion characterized by nodules of hyperplastic bone and thickening of the frontal bone's inner surface. Despite its prevalence in the general population and its long history of observation-it is one of the most frequently observed pathologies in gross anatomy laboratories-HFI's etiology and pathogenesis remain poorly understood. This is largely due to the lack of a thorough survey of its histology across the various stages of its development. Our study has three major aims: (1) assess HFI histology from incipient to advanced lesions; (2) elucidate lamellar and trabecular structure in HFI; and (3) clarify impacts/roles of the dura mater in HFI. Sections of nondecalcified bone provide evidence for two different categories of lesions: (1) stratum lesions, characterized by lamellar-based overall thickening of the internal table, and (2) eruptive lesions, characterized by nodular formations of initially lamellar bone that appear to form the bulk of bone mass in advanced stages. Sections of nondecalcified bone also suggest that for both lesion types, HFI growths begin as deposits of lamellar bone, which are later remodeled into woven bone deposits; our data do not support the hypothesis that lesions begin as a "diploization" of cortical bone as suggested by prior studies. Trichrome-stained sections provide evidence that growing lesions erode through and engulf the dura mater, effectively destroying this tissue layer as they grow laterally and inwardly. Our results indicate possible avenues of research to better understand the root causes of this disorder.

Hyperostosis frontalis interna on fluorine-18 sodium fluoride PET/computed tomography of obese cancer patients: a potential mimicker of metastasis

OBJECTIVE

The objective of this retrospective study was to identify the uptake patterns and suggest a quantitative method to detect hyperostosis frontalis interna (HFI) on fluorine-18 sodium fluoride ([ 18 F]NaF) PET/computed tomography (CT).

METHODS

Between January 2019 and December 2021, patients who underwent [ 18 F]NaF PET/CT with a BMI of 30 and above, were included. Three nuclear medicine consultants reviewed the studies to determine the presence and identify the uptake patterns of HFI. Quantitative evaluation was performed on PET images using the total number of counts over the frontal bone and the ratio of counts between the frontal bone and iliac crest.

RESULTS

A total of 105 out of 249 cases were included in this study. Among these scans, there were 67 positive HFI in [ 18 F]NaF PET scans representing 64% of the studied population. As for the [ 18 F]NaF PET uptake pattern, there were 53 with uniformly diffused and 14 with heterogeneous uptake pattern. There were 17 out of 67 with positive HFI in [ 18 F]NaF PET scans but negative CT scans.

CONCLUSION

HFI is a common finding on [ 18 F]NaF PET in obese patients and is probably underdiagnosed. HFI may present with a heterogeneous and diffuse pattern of uptake on [ 18 F]NaF PET. The proposed quantitative analysis using the count ratios is in agreement with the visual evaluation of [ 18 F]NaF PET images regardless of the CT findings. Awareness of this condition and its scintigraphic patterns is warranted since it can have clinical significance and may mimic other pathologies including metastasis in cancer patients.

Evaluation of Facial Aging in Different Age and Gender Groups With Computed Tomography-Based Calvarium and Face Measurements

BACKGROUND

The human face is a complex area formed by the combination of many different components and varies among individuals according to gender, age, and ethnicity.

OBJECTIVE

The aim of this study was to evaluate age-related changes in the facial and calvarial bones in a large sample of both genders.

METHODS

The retrospective study included nontraumatic brain computed tomography scans of 280 Turkish adults. Participants were divided into 7-decade groups with the age ranging from 20 to 89 years. Measurements of the face and calvaria were recorded, and calvarial volume was calculated. The relationship of these parameters with age and gender was examined.

RESULTS

Statistically significant differences were observed in all the facial and calvarial measurements, except the transverse diameter of the head, with increasing age in both genders. Regardless of age, no significant differences were found in facial and calvarial measurements between genders. In addition, there was a significant decrease in the calvarial volume in both genders after the seventh decade of life.

CONCLUSION

The structure of the face and calvarium continues to change and differentiate throughout life. Taking these changes into account during surgical and facial rejuvenation procedures can help predict outcomes and avoid the use of incorrect techniques.

The clinical manifestations of hyperostosis frontalis interna: A qualitative systematic review of cases

Hyperostosis frontalis interna (HFI) is a condition defined as abnormal bone growth on the posterior aspect of the frontal bone. Despite uncertainties regarding its etiology and prognosis, clinicians typically consider HFI a benign pathology. There are no studies organizing all the possible manifestations of the disease. The present study aims to organize all the clinical manifestations of HFI within the current case report/series literature. A blinded PRISMA-guided search of HFI case reports and case series yielded 43 relevant articles and provided 110 patients for analysis. The symptoms presenting alongside HFI were extracted and tabulated. We found high-frequency clinical manifestations of HFI (>20% of patients) to include headaches, obesity, vertigo/dizziness symptoms, cognitive decline, and depression. An additional 15 symptoms were tabulated at frequencies found to be less than 20%. Based on our analysis, we suggest the constellation of high-frequency symptoms can offer a more comprehensive clinical picture of symptomatic HFI which may be valuable to consider for clinicians and future researchers in the field of HFI.

Hyperostosis Fronto-Parieto-Occipitalis: A Cadaveric Case Report

Hyperostosis of the skull is a rare bone dysplasia described in disorders such as hyperostosis cranialis interna (HCI) and hyperostosis frontalis interna (HFI). Other syndromes presenting with hyperostosis include Morgagni-Stewart-Morel (MSM) and Troell-Junet. HCI is an abnormal hyperostosis of most endosteal skull and calvarium surface regions. A more specific hyperostosis, HFI, is an unusual bone growth based on its volume and porosity; it is primarily located bilaterally on the frontal portions of the calvarium. However, the hyperossification does not cross the superior sagittal sinus. Upon cadaveric dissection, we found hyperossification beyond the frontal area, extending to the parietal and occipital bones with the significant characteristic of no midline interference. Hyperossification results in gross indentations on the corresponding frontal, parietal, and occipital hemispheric brain tissues. This report discusses possible differentials for this rare cadaveric finding of frontal, parietal, and occipital bone hyperostosis. This case report includes some major characteristic features indicative of HCI and HFI with some interesting variations and features suggestive of MSM and Troell-Junet syndromes. Due to the lack of patient history and medical records, no further conclusions about clinical differentials, symptoms, or causative syndromes could be drawn; further research needs to be conducted on HCI, HFI, and related syndromes to understand their presentations better.

Hyperostosis frontalis interna presenting as a forehead scar in a young male

Hyperostosis frontalis interna is a benign overgrowth of the inner table of the frontal bone. Exact etiology is unknown. The condition is often an incidental finding and requires no treatment unless there are neurological signs and symptoms.

Frequency of hyperostosis frontalis interna in patients with active acromegaly: is there a possible role of GH excess or hyperprolactinemia in its etiopathogenesis?

PURPOSE

Acromegaly is characterized by bone changes due to excessive growth hormone (GH) secretion. Hyperostosis frontalis interna (HFI) is described as an overgrowth in the inner plate of the frontal bone. An increased incidence of HFI has been reported in patients with acromegaly. Since the etiology of HFI is poorly understood, we have analyzed whether there is a relationship between the hormonal and metabolic status of patients with acromegaly (with or without hyperprolactinemia) and the pathogenesis of HFI.

METHODS

Forty-five patients with acromegaly and two control groups consisting of 25 patients with prolactinoma (group 1) and 47 healthy subjects (group 2) were included in this retrospective study. Baseline hormonal data and cranial imaging were obtained from medical records and analyzed.

RESULTS

Mean frontal bone thickness was 6.75 mm in acromegaly, 4.85 mm in group 1, and 5.1 mm in group 2 of controls (p < 0.001). The frequency of HFI was higher in acromegalic patients than in the controls (22%, 0%, and 2.2%, respectively). There was no difference between the HFI positive and negative acromegalic patients in basal GH, IGF-1, and PRL levels, IGF-1 index, diagnosis lag time, and insulin resistance. There was no difference between groups regarding parietal and occipital bone thickness.

CONCLUSION

Although the frequency of HFI is 22% in patients with acromegaly, neither excess GH nor hyperprolactinemia plays a role in its etiopathogenesis. Various genetic or epigenetic factors may contribute to its etiology.

A Case Report of Hyperostosis Frontalis Interna

A routine dissection of an 89-year-old female cadaver who had died of cardiopulmonary arrest revealed a unique case of hyperostosis frontalis interna (HFI). Multiple layers of spongy bone growth deep to the internal table were coupled with asymmetrical nodular growths. Slight superior sagittal sinus growth was also noted, which is atypical of this condition. Additionally, this cadaver represents one of the rarer and more severe forms of HFI, class C. A clear consensus on whether HFI presents a clinical risk has not been reached. We hope that this report on a unique manifestation of HFI will help clinicians in evaluating patients with this condition.

Single-subject analysis of regional brain volumetric measures can be strongly influenced by the method for head size adjustment

Purpose

Total intracranial volume (TIV) is often a nuisance covariate in MRI-based brain volumetry. This study compared two TIV adjustment methods with respect to their impact on z-scores in single subject analyses of regional brain volume estimates.

Methods

Brain parenchyma, hippocampus, thalamus, and TIV were segmented in a normal database comprising 5059 T1w images. Regional volume estimates were adjusted for TIV using the residual method or the proportion method. Age was taken into account by regression with both methods. TIV- and age-adjusted regional volumes were transformed to z-scores and then compared between the two adjustment methods. Their impact on the detection of thalamus atrophy was tested in 127 patients with multiple sclerosis.

Results

The residual method removed the association with TIV in all regions. The proportion method resulted in a switch of the direction without relevant change of the strength of the association. The reduction of physiological between-subject variability was larger with the residual method than with the proportion method. The difference between z-scores obtained with the residual method versus the proportion method was strongly correlated with TIV. It was larger than one z-score point in 5% of the subjects. The area under the ROC curve of the TIV- and age-adjusted thalamus volume for identification of multiple sclerosis patients was larger with the residual method than with the proportion method (0.84 versus 0.79).

Conclusion

The residual method should be preferred for TIV and age adjustments of T1w-MRI-based brain volume estimates in single subject analyses.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-022-02961-6.

Hyperostosis in Combination With Low Skull Density Ratio: A Potential Contraindication for Magnetic Resonance Imaging-Guided Focused Ultrasound Thalamotomy

Since its approval in treating a number of movement disorders, magnetic resonance imaging–guided focused ultrasound (MRgFUS) has been adopted rapidly as one of the standard treatment modalities internationally. However, the efficiency of the energy delivered by the ultrasonic waves is largely determined by the highly variable bone morphology and density characteristics of the skull. One of the widely accepted indices used to facilitate patient selection is the skull density ratio (SDR). Earlier literature suggested that an SDR of less than 0.4 would be unfavorable for MRgFUS treatment. Some prior studies have excluded patients with hyperostosis. However, there is little published data regarding the impact of other skull features such as hyperostosis on treatment success. We present the case of a 66-year-old man with medically refractory essential tremor who had an SDR of 0.38 and extensive hyperostosis frontalis interna and underwent attempted MRgFUS thalamotomy treatment. However, intraoperatively the treatment was unsuccessful in generating sufficiently elevated temperature to create a lesion of the usual desired volume, and as expected, there was minimal clinical improvement. For comparison, we also summarize a case series of 4 other patients with an SDR of less than 0.4 who had successful outcomes. We believe that SDR should not be used as the only means of selecting patients for MRgFUS. Instead, important factors such as hyperostosis should be taken into consideration for patient selection and pretreatment counseling.

Imaging Spectrum of Calvarial Abnormalities

Calvarial abnormalities are usually discovered incidentally on radiologic studies or less commonly manifest with symptoms. This narrative review describes the imaging spectrum of the abnormal calvaria. The extent, multiplicity, and other imaging features of calvarial abnormalities can be combined with the clinical information to establish a final diagnosis or at least narrow the differential considerations. Prior trauma (congenital depression, leptomeningeal cysts, posttraumatic osteolysis), surgical intervention (flap osteonecrosis and burr holes), infection, and inflammatory processes (sarcoidosis) can result in focal bone loss, which may also be seen with idiopathic disorders without (bilateral parietal thinning and Gorham disease) or with (Parry-Romberg syndrome) atrophy of the overlying soft tissues. Anatomic variants (arachnoid granulations, venous lakes, parietal foramina) and certain congenital lesions (epidermoid and dermoid cysts, atretic encephalocele, sinus pericranii, and aplasia cutis congenita) manifest as solitary lytic lesions. Other congenital entities (lacunar skull and dysplasia) display a diffuse pattern of skull involvement. Several benign and malignant primary bone tumors involve the calvaria and manifest as lytic, sclerotic, mixed lytic and sclerotic, or thinning lesions, whereas multifocal disease is mainly due to hematologic or secondary malignancies. Metabolic disorders such as rickets, hyperparathyroidism, renal osteodystrophy, acromegaly, and Paget disease involve the calvaria in a more diffuse pattern. Online supplemental material is available for this article. ^©RSNA, 2021.

The Skinner Burial of Ontario, Canada, and the Question of Paget's Disease in the Americas

PURPOSE

To examine a possible case of Paget's disease of bone (PDB) in an Indigenous pre-contact male from Canada, individual D of the Skinner site in Ontario.

METHODS

Radiographs, CT scan and histological analysis.

RESULTS

The histological analysis revealed the mosaic pattern that characterizes PDB. CT scans show advanced sclerosis of the cranium and a diminished diplӧe with osteolytic lesions.

CONCLUSIONS

The pathological features that have been identified are collectively characteristic of PDB.

SIGNIFICANCE

The Skinner case advances our understanding of the global history and distribution of PDB.

LIMITATIONS OF STUDY

Only two New World cases have been identified and neither has been studied in sufficient detail.

SUGGESTIONS FOR FUTURE RESEARCH

The older individuals in precolonial New World skeletal series should be given CT scans, which are non-intrusive, to be followed by histological and genetic analyses when indicated.

Diffuse Calvarial Hyperostosis in Patients with Spontaneous Intracranial Hypotension

BACKGROUND

Diagnosis of spontaneous intracranial hypotension (SIH) may be delayed due to nonspecific symptoms and variable imaging findings. Cases of hyperostosis in children who are overshunted, a process that may be physiologically analogous to adults with SIH, have been reported by others and observed in our practice. The purpose of this retrospective study was to assess the frequency and pattern of calvarial hyperostosis in patients with SIH.

METHODS

We retrospectively reviewed computed tomography and magnetic resonance imaging examinations from consecutive patients who underwent myelography for the evaluation of SIH to assess for the presence of generalized calvarial thickening or development of a secondary layer of bone. Patients with typical benign hyperostosis frontalis were excluded. Patient demographics and clinical factors were evaluated for association with hyperostosis.

RESULTS

Among 285 patients with SIH, 40 (14.0%) demonstrated diffuse calvarial hyperostosis on imaging. Most of these patients (32/40; 80.0%) demonstrated a distinct circumferentially layered appearance to the skull, whereas 8 of 40 (20.0%) had generalized calvarial thickening without layering.

CONCLUSIONS

Diffuse calvarial hyperostosis, particularly the concentrically layered form that we term "layer cake skull," is a relatively common imaging feature in patients with SIH. In the appropriate clinical context, this finding will allow the possibility of SIH to be raised based on computed tomography imaging, which is otherwise of limited utility in the initial diagnosis of this condition.

Fibrous Dysplasia, Paget's Disease of Bone, and Other Uncommon Sclerotic Bone Lesions of the Craniofacial Bones

Imaging studies of the brain, head and neck, sinuses, and dental computed tomography are among the most frequently performed procedures in radiologic departments. Systematic evaluation in the bone window may reveal common and uncommon sclerotic osseous abnormalities of the craniofacial skeleton.Most of these findings are incidental and unrelated to the initial clinical indications. Sporadically symptoms may arise due to lesional mass effect with compression on adjacent structures and neuroforaminal encroachment, resulting in proptosis, vision, or hearing loss. Other symptoms include craniofacial deformity, mandibular occlusion deformity, and local pain.This article reviews the most common disorders characterized by an increased bone density involving the craniofacial bones including fibrous dysplasia, Paget's disease of bone, meningioma with associated hyperostosis, and osteoma. Finally, typical examples of rarer sclerosing bone dysplasias are discussed as well.Emphasis is placed on imaging features and the differential diagnosis.

Micro-computed Tomography Study of Frontal Bones in Males and Females with Hyperostosis Frontalis Interna

Hyperostosis frontalis interna (HFI) represents irregular thickening of the endocranial surface of the frontal bone, mostly seen in postmenopausal females. The microarchitecture of this condition is poorly studied. The aim of this cross-sectional autopsy study was to investigate and compare microarchitectural structure of the frontal bone affected with HFI in both sexes and to test whether HFI severity could be distinguished at the microarchitectural level. The sample was taken from human donor cadavers, 19 males (61 ± 15 years old) and 17 females (75 ± 15 years old). After classification of HFI severity (type A, B, C or D), samples of the frontal bone were taken and scanned using micro-computed tomography. Bone volume fraction was higher and total porosity lower only in the outer table of males with HFI, compared to females with HFI. Mean total sample thickness differed only between males with HFI type A and D. Bone microarchitecture between males and females with corresponding HFI types (e.g., male with type A versus female with type A) differed only in HFI type C regarding the fractal dimension of diploe. The degree of anisotropy differed between HFI subtypes in males, but the post hoc analysis revealed no significant differences between individual groups. Other microarchitectural parameters did not differ among males with different HFI subtypes, as well in females, in any part of the frontal bone. There is no difference in microarchitectural structure of the frontal bone between males and females with HFI, in general aspect and within corresponding HFI subtypes. HFI severity could not be distinguished at the microarchitectural level, neither in males nor in females.

Hyperostosis frontalis interna in ancient populations from the Carpathian Basin - A possible relationship between lifestyle and risk of development

OBJECTIVE

The prevalence of hyperostosis frontalis interna (HFI) was examined in different periods of the Carpathian Basin from 4900 BCE to 17th century AD. The study seeks to evaluate temporal changes in HFI and the possible impact of lifestyle on it.

MATERIALS

The studied material consisted of 4668 crania from Hungary and Serbia.

METHODS

The crania were analyzed employing macroscopic and endoscopic examination.

RESULTS

In historic periods, sex and age played a pivotal role in HFI development. Among predominantly pastoralist populations of the 5th-8th and 10th centuries, prevalence of HFI was considerably higher than in the medieval populations of the 9th-17th centuries.

CONCLUSIONS

In addition to age and sex, other factors could be implicated in HFI development. The physiological effects of the pastoralist lifestyle and diet on insulin regulation could explain the increased risk of developing HFI in the 5th-8th and 10th-century populations.

SIGNIFICANCE

The study provides the first comprehensive dataset of HFI from different archaeological periods from the Carpathian Basin. It has implications for lifestyle and risk of HFI development in past populations.

LIMITATIONS

The archaeological periods are not equally represented.

SUGGESTIONS FOR FURTHER RESEARCH

In order to better understand the etiology of HFI, lifestyle factors can be used to elucidate the risk of developing HFI in ancient populations.

Hyperostosis Frontalis Interna in a Child With Severe Traumatic Brain Injury

Hyperostosis frontalis interna is an unexplained irregular thickening of the inner table of the frontal bone. Hyperostosis frontalis interna was first identified in 1719 by Morgagni as a symptom of a more generalized syndrome characterized by virilism and obesity. Most current studies have shown hyperostosis frontalis interna to be a sex- and age-dependent phenomenon, and females manifest a significantly higher prevalence of hyperostosis frontalis interna than males. In this article, the authors report the clinical case of hyperostosis frontalis interna in a 7-year-old child who had severe traumatic brain injury in the past; review the related literature; and discuss the clinical, radiological, and therapeutic features of this condition.

Hyperostosis frontalis interna in female historic skeletal populations: Age, sex hormones and the impact of industrialization

OBJECTIVES

This analysis aims to investigate the impact of industrialization on the prevalence of Hyperostosis Frontalis Interna (HFI), focusing on the roles of age and parity to examine the claim that longevity and changing reproductive patterns have led to increased rates in modern populations.

MATERIALS AND METHODS

A total of 138 individuals from two documented London skeletal assemblages of the Industrial period were analyzed employing macroscopic observation, digital radiography and MicroCT scanning to establish the prevalence rates of HFI according to modern clinical standards. Statistical analysis was also undertaken on a sub-sample of 51 females of post-menopausal age to identify any relationship between parity and HFI.

RESULTS

The majority of cases of HFI were found in older females, reflecting clinical observations. The prevalence rates of HFI corresponded well to those predicted from the proportion of old age females present within populations. Age was therefore shown to be a predominant factor in HFI presence. A plateau in HFI prevalence was noted from the age of 50-59 years onwards. No statistically significant relationship was found between parity and HFI.

DISCUSSION

When recorded consistently, HFI was positively correlated with age and longevity but had also increased among old age females over time. Our results suggest that nulliparity co-occurs with HFI but is not a primary factor in its pathogenesis. Key factors in HFI presence in females are likely to be increased androgens and the dysregulation of insulin and insulin-like growth factor-1.

3D-Microarchitectural patterns of Hyperostosis frontalis interna: a micro-computed tomography study in aged women

Although seen frequently during dissections and autopsies, Hyperostosis frontalis interna (HFI) - a morphological pattern of the frontal bone thickening - is often ignored and its nature and development are not yet understood sufficiently. Current macroscopic classification defines four grades/stages of HFI based on the morphological appearance and size of the affected area; however, it is unclear if these stages also depict the successive phases in the HFI development. Here we assessed 3D-microarchitecture of the frontal bone in women with various degrees of HFI expression and in an age- and sex-matched control group, hypothesizing that the bone microarchitecture bears imprints of the pathogenesis of HFI and may clarify the phases of its development. Frontal bone samples were collected during routine autopsies from 20 women with HFI (age: 69.9 ± 11.1 years) and 14 women without HFI (age: 74.1 ± 9.7 years). We classified the HFI samples into four groups, each group demonstrating different macroscopic type or stage of HFI. All samples were scanned by micro-computed tomography to evaluate 3D bone microarchitecture in the following regions of interest: total sample, outer table, diploe and inner table. Our results revealed that, compared to the control group, the women with HFI showed a significantly increased bone volume fraction in the region of diploe, along with significantly thicker and more plate-like shaped trabeculae and reduced trabecular separation and connectivity density. Moreover, the inner table of the frontal bone in women with HFI displayed significantly increased total porosity and mean pore diameter compared to controls. Microstructural reorganization of the frontal bone in women with HFI was also reflected in significantly higher porosity and lower bone volume fraction in the inner vs. outer table due to an increased number of pores larger than 100 μm. The individual comparisons between the control group and different macroscopic stages of HFI revealed significant differences only between the control group and the morphologically most pronounced type of HFI. Our microarchitectural findings demonstrated clear differences between the HFI and the control group in the region of diploe and the inner table. Macroscopic grades of HFI could not be distinguished at the level of bone microarchitecture and their consecutive nature cannot be supported. Rather, our study suggests that only two different types of HFI (moderate and severe HFI) have microstructural justification and should be considered further. It is essential to record HFI systematically in human postmortem subjects to provide more data on the mechanisms of its development.

CT Examination of Nose and Paranasal Sinuses of Egyptian Mummies and Three Distinct Human Population Groups: Anthropological and Clinical Implications

The interaction of nasal morphology and climatic conditions has resulted in diverse hard- and soft-tissue configurations across human population groups. While the processes of skull pneumatization are not fully understood, the invasions of the paranasal sinuses [PNS] into the cranium have contributed to assorted morphologies. Human migratory patterns and the strong association with climatic variables through time and space may explain this diversity. This study examined four multiregional populations of which two are from Egypt but of widely divergent eras. Three Egyptian mummies [EG-M] from the middle kingdom were CT scanned providing a unique opportunity to investigate the status of PNS anatomy within a time frame from 1567 BCE to 600 CE and compare it to a contemporary Egyptian [EG] (n = 12) population. Dry skulls of Inuit [IT] (n = 10) and East African [EA] (n = 8) provide out-group comparisons, as one group represents an isolated geographic environment far different from that of Egypt and the other group inhabiting distinct environmental conditions albeit located within the same continent. Results showed EG-M and EG frontal sinus volumes were diminutive in size with no statistically significant difference between them. Maxillary sinus size values of EG-M and EG clustered together while IT and EA significantly differed from each other (P = 0.002). The multiregional groups exhibited population specific morphologies in their PNS anatomy. Ecogeographic localities revealed anatomical differences among IT and EA, while the potential time span of about 3,500 years produced only a negligible difference between the Egyptian groups. The small sample sizes incorporated into this research requires confirmation of the results by analyses of larger samples from each geographic region and with the integration of a larger group of Egyptian mummified remains.

Anatomical variations: How do surgical and radiology training programs teach and assess them in their training curricula?

Sound knowledge of anatomy and Anatomical variations plays an integral role in surgical and radiology specialties. This study investigated the current teaching and assessment trends on Anatomical variations in various surgical and radiology specialty training curricula in Canada and Australia. A survey was sent to 122 Program Directors and Chairs of specialty committees in Canada and Directors of Training/Education in Australia of selected surgical and radiology specialties. A total of 80.7% of respondents report that their training curricula include Anatomical variations. The highest rated classes of variations included in the curriculum are arterial (76%), venous (68%), followed by organs (64%). All trainees learn about Anatomical variations from surgeons and radiologists (100%) and via suggested textbooks of the specialty (87.1%). A total of 54.8% report that specialty training curricula do not suggest specific anatomical variation classifications for the trainees to learn, and 16.1% are uncertain if the colleges provide such kind of instruction. Trainees typically communicated findings of variations in case presentations and clinic's meetings. About 32.3% of respondents report that Anatomical variations are not assessed in their training curriculum. About 39.3% of experienced clinicians in the study report they encounter variations on a monthly basis and 25 and 21.4% on a weekly and daily basis, respectively. Surgical and radiology colleges need to investigate for hidden curriculum in their specialty training programs to ensure there are no gaps in knowledge and training related to Anatomical variations. Most educational leaders surveyed believe more teaching on Anatomical variations in the first 4 years of training would benefit resident doctors.

Evaluation of morphological changes in the adult skull with age and sex

The morphology of the brain and skull are important in the evaluation of the aging human; however, little is known about how the skull may change with age. The objective of this study was to evaluate the morphological changes of the adult skull using three-dimensional geometric morphometric analysis of thousands of landmarks with the focus on anatomic regions that may be correlated with brain atrophy and head injury. Computed tomography data were collected between ages 20 and 100. Each scan was segmented using thresholding techniques. An atlas image of a 50th percentile skull was registered to each subject scan by computing a series of rigid, affine, and non-linear transformations between atlas space and subject space. Landmarks on the atlas skull were transformed to each subject and partitioned into the inner and outer cranial vault and the cranial fossae. A generalized Procrustes analysis was completed for the landmark sets. The coordinate locations describing the shape of each region were regressed with age to generate a model predicting the landmark location with age. Permutation testing was performed to assess significant changes with age. For the males, all anatomic regions reveal significant changes in shape with age except for the posterior cranial fossa. For the females, only the middle cranial fossa and anterior cranial fossa were found to change significantly in shape. Results of this study are important for understanding the adult skull and how shape changes may pertain to brain atrophy, aging, and injury.