Skulls Research Articles

Application of augmented reality models of canine skull in veterinary anatomical education.

Veterinary anatomy plays a crucial role in the curriculum for veterinary medicine and surgery. The integration of modern information technology in veterinary education can greatly benefit from innovative tools such as augmented reality (AR) applications. The aim of this study was to develop an accurate and interactive three-dimensional (3D) digital model of an animal skull using AR technology, aiming to enhance the learning of skull anatomy in veterinary anatomy education. In this study, a canine skull specimen was isolated, and the skull bones were scanned using a structured light scanner to create a 3D digital model of the canine skull, which was found to be indistinguishable from the original specimen by measurement of skull proportions. Furthermore, the interactive AR model of the canine skull, displayed using Unity3D, was subjected to testing and evaluation by 60 first-year veterinary medical students attending the gross anatomy of the animal. The students were divided into two groups: the traditional group and AR group. Both groups completed an objective test and a questionnaire. The evaluation of learning effectiveness in the test revealed no significant difference between the traditional group (which learned using textbooks and a canine skull specimen) and AR group (which learned using AR tools). However, in the questionnaire, students displayed high enthusiasm and interest in using the AR tool. Therefore, the application of AR tools can improve students' motivation for learning and enhance the comprehension of anatomical structures in three dimensions. Furthermore, this study exemplifies the use of AR as an auxiliary tool for teaching and learning in veterinary anatomy education.

Controlled noninvasive modulation of deep brain regions in humans

Transcranial focused ultrasound provides noninvasive and reversible approaches for precise and personalized manipulations of brain circuits, with the potential to transform our understanding of brain function and treatments of brain dysfunction. However, effective applications in humans have been limited by the human head, which attenuates and distorts ultrasound severely and unpredictably. This has led to uncertain ultrasound intensities delivered into the brain. Here, we address this lingering barrier using a direct measurement approach that can be repeatedly applied to the human brain. The approach uses an ultrasonic scan of the head to measure and compensate for the attenuation of the ultrasound by all obstacles within the ultrasound path. No other imaging modality is required and the method is parameter-free and personalized to each subject. The approach accurately restores operators’ intended intensities inside ex-vivo human skulls. Moreover, the approach is critical for effective modulation of deep brain regions in humans. When applied, the approach modulates fMRI Blood Oxygen Level Dependent (BOLD) activity in disease-relevant deep brain regions. This tool unlocks the potential of emerging approaches based on low-intensity ultrasound for controlled manipulations of neural circuits in humans.

A Quantitative Evaluation of the Effectiveness of the Metal Artifact Reduction Algorithm in Cone Beam Computed Tomographic Images with Stainless Steel Orthodontic Brackets and Arch Wires: An Ex Vivo Study.

The presence of high-density and high-atomic number materials results in the generation of artifacts in cone beam computed tomographic (CBCT) images. To minimize artifacts in CBCT images, the metal artifact reduction (MAR) tool was developed. This study aims to quantitatively evaluate the effectiveness of the MAR algorithm in CBCT images of teeth with stainless steel orthodontic brackets with or without arch wires in buccal and lingual positions obtained using the Galileos Sirona CBCT scanner. In this in vitro study, 20 stainless steel brackets were attached to the maxillary dentition from the right second premolar to the left second premolar teeth of a human skull. In the first group, 10 brackets were bonded to the buccal surface, and in the second group, 10 brackets were bonded to the palatal surface of these teeth. CBCT scans were obtained for each group with or without orthodontic stainless steel wires using a Galileos Sirona CBCT scanner with exposure parameters of 85 kVp and 21 mAs. CBCT images were obtained two times with and two times without MAR activation. The DICOM format of the CBCT images was imported to ImageJ software (version 1.54), and the contrast-to-noise ratio (CNR) was calculated and compared for each bracket in 15 and 20 mm distances and 20, 40, and 90 degrees on each side. Statistical analysis was performed using the t test (α = 0.05). CNR values of different distances and different teeth were not significantly different between the two MAR modes (p > 0.05). MAR activation had a significant impact in increasing CNR and reducing artifacts only when brackets were in palatal (p = 0.03). In the other bracket and wire positions, the effect of the MAR algorithm on CNR was not significant (p > 0.05). In conclusion, MAR activation significantly increased CNR, but only when the brackets were in a palatal position. In the other bracket and wire positions, the effect of the MAR algorithm is not significant.

Morphometric Comparison of Endoscopic Endonasal Transpterygoid and Precaruncular Contralateral Medial Transorbital Approaches to Sphenoid Sinus Lateral Recess.

The endoscopic endonasal transpterygoid approach (TPA), minimally invasive compared with the sublabial transmaxillary and transcranial approaches, still accounts for morbidity in benign lateral recess of sphenoid sinus (LRSS) pathologies. Others have suggested an alternative route to the LRSS, the endoscopic contralateral medial transorbital approach (cMTO). However, no quantitative evidence exists to support the clinical application of this approach. This cadaveric study, in a controlled laboratory setting, provides a morphometric comparison of the TPA and cMTO for accessing the LRSS. The study also details the anatomy and technical nuances for optimizing the cMTO corridor. Ten fresh preinjected human cadaveric specimens (20 sides) were dissected with neuronavigation, completing endoscopic cMTO and TPA on each side. Four parameters-working distance to lateral recess, surgical exposure area, angle of attack (AoA), and surgical freedom-were measured for each approach. Relevant osteological measurements in 10 dried human skulls were recorded. The mean distance from the superior margin of the lacrimal sac impression to the inferior margin of the trochlear fossa was 10.29 ± 1.13 mm, and that from the anterior ethmoidal artery foramina to the posterior lacrimal crest was 9.63 ± 1.23 mm. The mean exposure area around the LRSS was significantly higher in TPA (614.09 ± 40.38 mm2) than in cMTO (391.19 ± 59.01 mm2, P = .001). The mean AoA was 9.83° and 10.24° in the cMTO and TPA, respectively, in the craniocaudal direction (P = .529). In the horizontal plane, it was 9.29° and 10.76° (P = .012). There was no significant difference in surgical freedom between the cMTO and TPA (804.61 and 806.05 mm3, respectively; P = .993). Although comparatively limited exposure area, the cMTO approach has a similar AoA and surgical freedom as TPA and offers better visualization and ergonomic advantages. cMTO provides a feasible, less morbid, multiport technique for benign sphenoid sinus lateral recess pathologies.

A Cross-sectional Study of Wormian Bones in the Cranium: Exploring their Clinical Significance and Diagnostic Implications

Introduction: Wormian Bones (WBs) are small, irregularly shaped ossicles often located within the cranial sutures and at the fontanelles, with the majority found in the lambdoid sutures. They result from the formation of abnormal ossification centres in the cranium that develop through an unknown mechanism. Clinically, Significant Wormian bones (SWBs) are defined as bones arranged in a general mosaic-like pattern with a size larger than 6×4 mm; for pathological significance, more than 10 such SWBs should be present. Aim: To study the incidence of WBs in various sutures of human dry skulls and to investigate the incidence of the metopic suture and Inca bone in human dry skulls. Materials and Methods: The present cross-sectional study was conducted in the Department of Anatomy, Government Doon Medical College, Dehradun, Uttarakhand, India, from January 2024 to May 2024. In the present study, 38 dried adult human skulls of unknown age and sex were examined for the presence, number and location of WBs, the metopic suture, and the Inca bone in various sutures of the skull. The data were analysed using descriptive statistics, and results were expressed in terms of incidence. Results: Wormian bones were present in 21 (55.26%) skulls, while 17 (44.74%) had no WBs. One (0.27%) skull had a metopic suture, and 1 (0.27%) skull had an Inca bone. Pathologically significant WBs were not found in any of the skulls examined. Conclusion: The overall incidence of WBs is 55.26%, while the incidences of the metopic suture and Inca bone are both 2.63%. Thus, WBs may mimic a cranial fracture, leading to misdiagnosis, which could delay or alter treatment. Additionally, some WBs may be lost during putrefaction, giving the appearance of an entry/exit gunshot wound in postmortem cases.

Transcranial Phase Correction Using Pulse-Echo Ultrasound and Deep Learning: A 2-D Numerical Study.

Phase aberration caused by human skulls severely degrades the quality of transcranial ultrasound images, posing a major challenge in the practical application of transcranial ultrasound techniques in adults. Aberration can be corrected if the skull profile (i.e., thickness distribution) and speed of sound (SOS) are known. However, accurately estimating the skull profile and SOS using ultrasound with a physics-based approach is challenging due to the complexity of the interaction between ultrasound and the skull. A deep learning approach is proposed herein to estimate the skull profile and SOS using ultrasound radiofrequency (RF) signals backscattered from the skull. A numerical study was performed to test the approach's feasibility. Realistic numerical skull models were constructed from computed tomography (CT) scans of five ex vivo human skulls in this numerical study. Acoustic simulations were performed on 3595 skull segments to generate array-based ultrasound backscattered signals. A deep learning model was developed and trained to estimate skull thickness and SOS from RF channel data. The trained model was shown to be highly accurate. The mean absolute error (MAE) was 0.15 mm (2% error) for thickness estimation and 13 m/s (0.5% error) for SOS estimation. The Pearson correlation coefficient between the estimated and ground-truth values was 0.99 for thickness and 0.95 for SOS. Aberration correction performed using deep-learning-estimated skull thickness and SOS values yielded significantly improved beam focusing (e.g., narrower beams) and transcranial imaging quality (e.g., improved spatial resolution and reduced artifacts) compared with no aberration correction. The results demonstrate the feasibility of the proposed approach for transcranial phase aberration correction.

Cranial anatomy of Indohyus indirae (Raoellidae), an artiodactyl from the Eocene of India, and its implications for raoellid biology

Cranial anatomy of Indohyus indirae (Raoellidae), an artiodactyl from the Eocene of India, and its implications for raoellid biology

Occurrence of a Persistent Mendosal Suture in an Ancient Adult Human Cranium From India

Occurrence of a Persistent Mendosal Suture in an Ancient Adult Human Cranium From India

3D Transcranial ultrasound localization microscopy reveals major arteries in the sheep brain.

Cerebral circulation ensures the proper functioning of the entire human body, and its interruption, i.e. stroke, leads to irreversible damage. However, tools for observing cerebral circulation are still lacking. Although MRI and CT scans serve as conventional methods, their accessibility remains a challenge, prompting exploration into alternative, portable, and non-ionizing imaging solutions like ultrasound with reduced costs. While Ultrasound Localization Microscopy (ULM) displays potential in high-resolution vessel imaging, its 2D constraints limit its emergency utility. This study delves into the feasibility of 3D ULM with multiplexed probe for transcranial vessel imaging in sheep brains, emulating human skull characteristics. Three sheep underwent 3D ULM imaging, compared with angiographic MRI, while skull characterization was conducted in vivo using ultrashort bone MRI sequences and ex vivo via micro CT. The study showcased 3D ULM's ability to highlight vessels, down to the Circle of Willis, yet within a confined 3D field-of-view. Future enhancements in signal, aberration correction, and human trials hold promise for a portable, volumetric, transcranial ultrasound angiography system.

Morphological and Morphometric Study of Greater Palatine Foramen in Dry Skulls of Eastern Indian Population

Abstract Background: Greater palatine foramen (GPF) transmits important neurovascular structures which may get injured during different operative procedures such as intraoral maxillary nerve block, cleft palate repair, and operative procedures involving maxillary sinus and maxillary molars. Hence, proper knowledge about the GPF is very essential. The aim of this study was to study the shape of GPF and its location in relation to molar tooth, measure the diameters of GPF, and measure the distances of GPF from different landmarks of palate. Methodology: A dry bone-based study was conducted on dry human skulls of Eastern Indian population using digital Vernier caliper. At first location of GPF in relation to maxillary molars was noted, followed by anteroposterior (AP) and transverse diameter of GPF and distance of GPF from incisive fossa, posterior border of hard palate (PBHP) and interpalatine suture was measured. Results: In 69.64% of cases, GPF was present medial to the maxillary molar tooth and most common shape is oval type which is found in 44.64% of cases. AP diameter was almost same in both the sides which is 5.13 mm in average and transverse diameter is 2.91 mm. The mean distance of GPF from incisive fossa, PBHP, and interpalatine suture (IPS) is as follows in sequence, 37.24 mm, 3.21 mm, and 13.68 mm. Conclusion: The findings from the present study can be used as a guide for locating GPF during different operative procedures such as palatal reconstruction in cleft palate, maxillary surgeries, and intraoral maxillary nerve block. GPF is located about 3 mm in front of PBHP, most commonly medial to the third maxillary molar, about 15 mm lateral to IPS in the present study among Eastern Indian population.

Template-based target point localization for occlusion of the middle meningeal artery during evacuation of space-occupying chronic subdural hematoma.

Endovascular middle meningeal artery (MMA) occlusion may help reduce the risk of recurrence after burr hole evacuation of chronic subdural hematoma (cSDH) but carries an additional periprocedural risk and remains hampered by logistical and financial requirements. In this study, the authors aimed to describe a simple and fast technique for preoperative MMA localization to permit burr hole cSDH evacuation and MMA occlusion through the same burr hole. The authors performed a preclinical anatomical and prospective clinical study, followed by a retrospective feasibility analysis. An anatomical cadaver study with 33 adult human skulls (66 hemispheres) was used to localize a suitable frontal target point above the pterion, where the MMA can be accessed via burr hole trephination. Based on anatomical landmark measurements, the authors designed a template for projected localization of this target point onto the skin. Next, the validity of the template was tested using image guidance in 10 consecutive patients undergoing elective pterional craniotomy, and the feasibility of the target point localization for cSDH accessibility was determined based on hematoma localization in 237 patients who were treated for a space-occupying cSDH in the authors' department between 2014 and 2018. In the anatomical study, the mean perpendicular distance from the zygomatic process to the target point in the frontoparietal bone was 4.1 cm (95% CI 4-4.2 cm). The mean length along the upper margin of the zygomatic process from the middle of the external auditory canal to the point of the perpendicular distance was 2.3 cm (95% CI 2.2-2.4 cm). The template designed according to these measurements yielded high agreement between the template-based target point and the proximal MMA groove inside the frontoparietal bone (right 90.9%; left 93.6%). In the clinical validation, we noted a mean distance of 4 mm (95% CI 2.1-5.9 mm) from the template-based target point to the actual MMA localization. The feasibility analysis yielded that 95% of all cSDHs in this cohort would have been accessible by the new frontal burr hole localization. A template-based target point approach for MMA localization may serve as a simple, fast, reliable, and cost-effective technique for surgical evacuation of space-occupying cSDHs with MMA obliteration through the same burr hole in a single setting.

The Erratic History of Electroencephalography

The history of electroencephalography begins around 1850 with a supposition of Emil du Bois-Reymond concerning the transfer of information by electric currents over the nerve to the effector. Luigi Galvani in Bologna showed with his frog legs experiments 1786 indeed the existence of animal electricity. Richard Caton in Liverpool placed in 1875 as the first electrodes on the brains of rabbits and was able to record the electrical brain activity. Caton received little attention for his research and left with his animal experiment aversion the field. In contrast to Caton, Adolf Beck in Kraków, got a huge attention for his recordings of the electrical activities of the frog brain. The most interesting response to his important paper of 1890 came from Vasili Danilewski from Charkov, mentioning his unpublished doctoral thesis of 1877. He did his dog recordings before Beck, but one year after Caton who send him his abstract, remaining that he discovered before him electric brain waves. Colleagues of Danilewski such as Práwdicz- Neminski from Kyiv performed also adequate work in this field, but due to Stalin's dogmatic regime, electrophysiology became prohibited and disappeared in Russian. Jewish Adolf Beck, now professor in Lwów, experienced there in war time in 1940 dangerous times and ultimately the Nazi’s came for him. His son succeeded to hand him a cyanide capsule to save him from the gas chamber. By the tragedies of the war in Poland and the split between East and West Europe, Beck and his work go lost. Hans Berger began in Jena with brain recordings in humans and in 1927 he exclaimed ‘I can record brain actvity from an intact human skull’. This was replicated abd agreed upon by Edgar Adrian in 1934, and Berger received international fame, but not in Germany. The often authoritative Berger hated the Nazi’s and was suspended by the regime. He came in a severe depression and ended his life by hanging in June 1941. In this heavy war time, electrophysiology moved to the USA. Frederic and Erna Gibbs at Harvard got, with their studies of epilepsy in 1934 a breakthrough in clinical electroencephalography, Alfred Loomis and Herbert Jasper used the electrical brain actvity to identify several stages of sleep. Later, Jasper performed in Montreal, with neurosurgeon Wilder Penfield, important research on focal epilepsies. After the second world war, around 1950, electroencephalography blossomed up, in the USA as well as in Europe. Recording electroencephalograms for studying the functioning of the brain and in particular investigating domains of sleep and epilepsy. It became common that almost every university and hospital had a resording device. That electroencephalography was a mature methodology, was demonstrated by great discoveries for example through the finding of REM sleep by Kleitman and Aserinski in 1953.

Determination of Sexual Dimorphism from Foramen Magnum in an Eastern Indian Population

Human identification is an important arena of forensic investigation, it includes sex determination which becomes extremely difficult in fragmented skeletal remains. Skull dimensions are measured for the purpose of sexual dimorphism which vary in different populations. In this study, we attempted to analyse the measurements from adult human skulls and employ discriminant function to predict sex accurately. A manual vernier calliper was used to measure the antero-posterior (AP) diameter and transverse diameter of foramen magnum of 88 skulls (49 males, 39 females) from the collection housed at the department of Anatomy, RG KAR medical college and Calcutta medical college. The Wilk's lambda for the model is 0.795. The discriminant function equation is, Df= 3.342× (APdiameter of foramen magnum) +0.725× (Transverse diameter of foramen magnum) -13.641(constant). The cut-off point is 0.505. So above this value 0.505, the cases are male and below it, the cases are female. On comparing the measurements, we found that antero-posterior dimensions and transverse dimensions of foramen magnum were greater in males than females. Collectively, all the results indicate that dimensions of foramen magnum can be used as a moderate indicator for sex determination in regional populations.

Osteological Analysis of Hard Palate in North Indian Skulls and its Forensic Significance: A Cross-sectional Study

Introduction: Various therapeutic procedures, such as cleft palate surgery, uvulopalatopharyngoplasty, nasopharyngoscopy, and nasogastric intubation, rely on the morphometric measurements of the hard palate. Additionally, it plays a crucial role in passive speech articulation. Therefore, understanding the morphological and osteological diversity of the hard palate holds clinical significance. Aim: To assess the normal and aberrant morphology and morphometry of the hard palate. Materials and Methods: The present cross-sectional study was initiated in December 2017 and completed in December 2021. It was conducted on 100 dry adult human skulls collected from the Department of Anatomy, Government Medical College, Amritsar, Punjab, India. The palate was analysed to determine the mean palatal length, breadth, and height. Additionally, the palatal index and palatal height index were calculated. Different osteological parameters of the lesser palatine foramen, including its number, distance from the greater palatine foramen, palatomaxillary suture, and interpalatine suture, were measured. Mean, standard deviation, range, and p-value were calculated for the metric parameters. Results: The mean palatal length, breadth, and height were 46.16±4.18 mm, 33.01±2.67 mm, and 11.06±1.88 mm, respectively. In the present study, 83% of skulls belonged to the leptostaphyline type, 10% to the mesostaphyline type, and 7% to the brachystaphyline type. The number of lesser palatine foramen varied from 0-2 on both sides, with predominance of a single foramen on both sides. The distances of the lesser palatine foramen from the greater palatine foramen, palatomaxillary suture, and intermaxillary suture were found to be 3.55±1.56 mm, 11.45±2.42 mm, and 17.57±3.06 mm on the right side, and 3.38±1.57 mm, 10.90±2.39 mm, and 17.47±2.99 mm on the left side, respectively. Conclusion: The data provided by this study will be helpful in various disciplines of medical, dental, and anthropometrical sciences.

Diachronic Comparison of Three Historical Skeletal Series from Croatia with Regard to Mandibular Bone Quality

The aim of this study was to assess the quality of mandibular bone using CBCT images in archeological populations that inhabited Croatia from the medieval to the Early Modern Period. A total of 88 human skulls (45 male and 43 female) from three samples (pre-Ottoman (N = 27), Ottoman (N = 32), and Vlach (N = 29)) were analyzed by using CBCT. The mental index, gonion index, antegonion index, panoramic mandibular index, degree of resorption of the alveolar ridge, and cortical index of the mandible were evaluated using the OnDemand3DApp. The results showed an expected higher value of cortex thickness in males when compared to females. Females in the younger groups had higher values of cortical thickness than those in the older age group. The Ottoman sample had significantly lower values of mandibular indices than the other two samples. There were no age-related differences in bone thickness in males, suggesting that hormonal changes have a stronger influence in females. Lower values of mandibular indices in the Ottoman sample may be an indicator of specific factors that influenced this population. Our study of bone changes in archeological populations with different living conditions may contribute to a better understanding of impact of biocultural factors on physiological and pathological processes, which are extremely complex in bone tissue.

Morphological analysis of the hypoglossal canal and its relationship with surrounding anatomical structures

Aim: The aim of this study was to investigate the hypoglossal canal morphologically and to emphasize the importance of its relation to the adjacent anatomical structures, which may affect some surgical procedures, such as the transcondylar surgical approach. Methods: In the study, 25 adult human skulls belonging to Bursa Uludağ University Anatomy Laboratories were evaluated. The 22 parameters were measured on the skulls. Results: The distance between the hypoglossal canal and the anterior border of the occipital condyle was found to be 15.8±2.8 mm on the left side and 15.8±3.1 mm on the right side. The external distance between the hypoglossal canal and the anterior border of the occipital condyle was found to be 11.5±2 mm on the left and 11.6±2 mm on the right. The distance between the hypoglossal canal and the posterior margin of the occipital condyle was 11.7±1.8 mm on the left side and 12.2±2.1 mm on the right side. Furthermore, the distance measured externally between the same anatomical structures was found to be 14.04±1.89 mm and 14.4±1.6 mm on the left and right, respectively. We also found a positive correlation between the length of the foramen magnum and the occipital condyle. In addition, the diameter of the foramen magnum and the distance between the hypoglossal canal and the anterior margin of the occipital condyle were positively correlated. Conclusion: In the transcondylar approach, the locations of important anatomical structures must be well known to perform a safe occipital condyle resection without harming the neural tissue. Especially surgeons should pay attention to the distances between the hypoglossal canal and the anterior and posterior margins of the occipital condyle in order to prevent hypoglossal nerve injury. The operational success of a condylectomy may be affected by the length of the hypoglossal canal. A detailed anatomical assessment is needed before similar procedures to avoid surgical injuries. How to cite this article: Yıldız Yılmaz M, Babacan S, Kafa İM, Coşkun İ. Morphological analysis of the hypoglossal canal and its relationship with surrounding anatomical structures. J Med Dent Invest 2023; 4: e230343. https://doi.org/10.5577/jomdi.e230343

The development of a 1.25 MHz 1024-channel sparse array for human transcranial imaging: in vitro characterization

Ultrasound imaging is overwhelmingly used as 2D modality even though 3D imaging capabilities have existed for decades. Recent generational shifts toward super-resolution ultrasound imaging and functional ultrasound imaging, especially in the brain, have generated renewed and sustained interest in acquiring truly volumetric, 4D data. However, volumetric imaging approaches are currently limited to small animals, due in part to the difficulty of imaging transcranially in humans and due to a lack of imaging arrays designed for this purpose. Clinical translation of these recent techniques as well as conventional diagnostic B-mode imaging may thus benefit from array designs that capitalize on large channel count imaging systems. We have designed and developed a 1024-channel sparse array with a 65 mm circular aperture and a 1–2 MHz bandwidth. This unique transducer achieves an aperture that is far larger than conventional matrix probes using a sparse arrangement of elements ordered in a density-tapered spiral design. This design has significantly decreased grating lobes compared to a matrix array probe. The large aperture of this probe also enables acquisition over a large field of view with a significant depth of more than 100 mm. Simulations, acoustic characterization, and in vitro tests demonstrate that this transducer achieves a high focal gain that enables ultrasonic visualization beneath the human skull and at large depths due to its low F-number capabilities. Furthermore, we show that this transducer is capable of high point target contrast and high soft tissue contrast, with contrast-to-noise ratios up to 1.9 when imaging transcranially through a 3 mm thick section of human skull. Because of the large surface area of this probe, it can capture over 3 coherence lengths in each dimension and is, therefore, able to able to ‘average out’ the aberration over a large surface area. This transducer is poised to have a significant clinical impact in transcranial human imaging.

Atlanto-occipital fusion: Case report

The article discusses cranio-cervical joints, specifically the atlanto-occipital and atlantoaxial joints. The atlanto-occipital joints include the occipital condyle and the superior articular surfaces of the first cervical vertebra (C1 or Atlas), allowing flexion, extension and lateral tilt of the head. The atlantoaxial joints include C1 and C2 (Axis) vertebrae, enabling rotation. Atlanto-occipital fusion is a rare congenital condition in which C1 fuses with the occipital bone of the skull. This can lead to narrowing of the Foramen Magnum, with or without compression of central structures (spinal cord or brain stem). Although this condition can be asymptomatic, when associated with other cranio-cervical anomalies, such as Basilar Invagination and Platybasia, it can bring instability to the neck, in addition to tonsillar herniation, neural compression and cerebral ischemia. This condition is related to an embryonic malformation of the Pro Atlas, which can occur in different regions of the joint. Furthermore, the type of fusion can vary, eventually resulting in stress at the C1-C2 junction, leading to subluxations and neurovascular complications. Despite its rarity, preoperative diagnosis using computed tomography or magnetic resonance imaging is essential to identify these changes and avoid injuries during surgery. In conclusion, atlanto-occipital fusion is a rare condition that, when associated with other anomalies, can cause damage to the central nervous system, highlighting the importance of adequate diagnosis and treatment. The objective of the study is to illustrate, discuss and investigate the prevalence of atlanto-occipital fusion in human skulls, which the authors found one case among the 117 skulls analyzed.

Peculiarities of the parietal bones of the vault of the human skull structure and shape, taking into account sex and craniotype

The development of neurosurgery and the increase in requirements for the performance of surgical approaches performed through the bones of the skull vault lead to the formation of new requests for detailing and clarification of the craniometric characteristics of the parietal bones. The purpose of our study is to establish the features of the shape and other spatial indicators of the parietal bones of the skull of a mature person, taking into account sex and certain types of craniotype. The study was conducted on 130 studied preparations of bone structures of the head of adults from the collected collection of the Department of Normal Anatomy of the Kharkiv National Medical University, in the amount of 82 bone preparations, including isolated parietal bones, as well as 48 tomograms obtained during the examination of patients. The basis for establishing a craniotype is the principle of calculating the cranial index. For statistical analysis, we used the programs Statistica 13.5.0.17 (trial version) and Microsoft Excel of the corporate package MS 365. To establish the peculiarities of the structure and shape of the parietal bones, the following craniometric indicators were determined: the length and width of the parietal tubers, the parietal chord and the arch, calculated the curvature index of the parietal bone. The obtained data were analyzed for mature people of different genders and three established craniotypes. It has been established that brachycephals are characterized by an expanded and expanded form of the parietal bones, which is associated with the predominance of the transverse dimensions of the entire cerebral skull. For mesocephals, the most typical intermediate- average form depending on the values of the cranial index. Dolichocephals have an elongated and narrowed form of the parietal bones, which is combined with general changes in the cerebral skull. Additional linear parameters of the parietal bones are directly dependent on the established craniotype. The dolichocephalic type is characterized by maximum length values of parietal tubers: ¯x =18.43 mm (right) and ¯x =18.24 mm (left) with minimum width parameters: up to ¯x =15.71 mm and ¯x =15.02 mm. Representatives of the brachycranic type are characterized by the minimum indicators of the length of the parietal tubers: from ¯x =12.73 mm to ¯x =12.81 mm and the maximum indicators for the width - ¯x =23.52 mm (right) and ¯x =23.04 mm (left). The parietal chord, like the parietal arch, had a similar trend in the distribution of indicators, namely: an increase from dolichocrania to brachycrania. In men with a dolichocephalic type of skull structure, the average values of these parameters were at the level of ¯x =108.2 mm (right) and 107.6 mm (left) for the parietal chord, and ¯x =114.2 mm and ¯x =113.2 mm for the parietal arcs In men with brachycranic type, the parietal chord reached - ¯x =116.6 mm (right) and ¯x =115.8 mm (left), and the parietal arch reached - ¯x =127.8 mm (right) and ¯x =126.9 mm ( left). In women, a similar principle of size distribution has been established, taking into account a small, 2-3 mm, general decrease in indicators compared to men. The curvature index of the parietal bones was determined: the maximum average values ¯x =83.00-83.58 were obtained in dolichocephals, the minimum values were ¯x =80.56-81.64 in brachycephals. This indicates an increase in the curvature of bones in brachycephals, given that the absolute value of the index is inversely proportional to the degree of curvature. Thus, the obtained data indicate a stable relationship between the craniotype of the skull and additional parameters of the parietal bones.

Beyond the walls: the design and development of the Petralona Cave virtual museum utilising 3D technologies

The Petralona Cave, which local inhabitants discovered by chance in 1959, is a remarkable natural and cultural landmark close to the village of Petralona, in the Chalkidiki peninsula of Greece. The site has gained global recognition for the discovery of a remarkably well-preserved Palaeolithic human skull, unearthed in 1960; it also holds archaeological and palaeontological significance. In this paper, the researchers introduce the Petralona Cave Virtual Museum: an innovative project whose mission is to increase public awareness and comprehension of the site. Our approach goes beyond mere replication of the physical museum located close to the cave; instead, the objective is to create an independent and comprehensive experience that is accessible to all visitors, irrespective of their ability to visit the site in person. Our methodology involved the documentation of the site and its history, analysis of user requirements, development of use cases to steer the design process, as well as architectural designs creation, itineraries and findings digitisation, and architectural structure finalisation. The Virtual Museum provides a well-organised frame structure that serves as an efficient gateway to the content, making navigation easy for visitors. Thanks to various presentation methods, including videos, high-quality images, interactive maps, animated content, interactive 3D models, plus searchable item libraries, among others, users are empowered to create a highly personalised navigation plan; thus the Virtual Museum experience is comparable to visiting the physical museum or cultural site. Cutting-edge digitisation techniques were employed to create highly detailed 3D models of the site. The Petralona Cave Virtual Museum is expected to offer an immersive experience, engaging diverse audiences; the interactive and educational exploration provides highly innovative access to archaeological knowledge. The visibility of the Petralona site is amplified and there is a significant contribution to knowledge dissemination about this important cultural heritage site.