Osteological Study of the Parietal Foramen in the Adult Human Skull Bones and its Clinical and Surgical Correlations / Estudio Osteológico del Foramen Parietal en los Huesos del Cráneo Humano Adulto y sus Correlaciones Clínicas y Quirúrgicas

SUMMARY: Parietal emissary foramina (PEF) are small holes, which are localized between the middle and posterior thirds of the parietal bone posterior surface close to the sagittal suture. PEF are important structures that protect the parietal emissary vein, which passes through it. During neurosurgery procedures, parietal foramina (PF) knowledge is crucial. This work aimed to evaluate presence and location of the PF in the skull of an adult human. Moreover, measure the distance amidst PF and the sagittal suture's midline to ascertain its clinical repercussions. 74 adult human skulls, without gross pathology, were observed for the PF's existence. The PF's and sagittal suture's midline distance were measured. According to the PF patterns of presence, five groups were distributed. Finally, specimens were photographed and subjected to statistical analysis. The PF was absent in 7 skulls (9.5 %). There were 9 skulls (12.2 %) exhibited central parietal foramen where the parietal foramen lies on the sagittal suture. 17 skulls (23 %) showed right unilateral parietal foramen, whereas 15 skulls (20.3 %) demonstrated left unilateral parietal foramen. The final 26 skulls (35.1 %) exhibited bilateral parietal foramen. This descriptive study supplies valuable information of PF variations, which is crucial for neurosurgeons in modifying surgical techniques and procedures to alleviate injury to PF-emerging structures such as emissary veins.

Los forámenes emisarios parietales (FEP) son pequeños orificios que se localizan entre los tercios medio y posterior de la superficie posterior del hueso parietal, cerca de la sutura sagital. Los FEP son estructuras importantes que protegen la vena emisaria parietal, que lo atraviesa. Durante los procedimientos de neurocirugía, el conocimiento de los forámenes parietales (FP) es crucial. Este trabajo tuvo como objetivo evaluar la presencia y ubicación del FP en el cráneo de hombres adultos, además, medir la distancia entre el FP y la línea mediana de la sutura sagital para conocer su repercusión clínica. Se examinaron 74 cráneos humanos adultos, sin patología grave, para determinar la existencia del FP. Se midió la distancia de la línea mediana de la sutura sagital y del FP. De acuerdo con los patrones de presencia del FP, se distribuyeron en cinco grupos. Finalmente, los especímenes fueron fotografiados y sometidos a análisis estadístico. El PF estaba ausente en 7 cráneos (9,5 %). Hubo 9 cráneos (12,2 %) que presentaban un PF central localizándose en la sutura sagital. 17 cráneos (23 %) presentaban un FP unilateral derecho, mientras que 15 cráneos (20,3 %) se observó un FP unilateral izquierdo. Los 26 cráneos restantes (35,1 %) exhibieron FP bilaterales. Este estudio descriptivo proporciona información valiosa sobre las variaciones del FP, que es fundamental para los neurocirujanos en el momento de modificar las técnicas y los procedimientos quirúrgicos para aliviar las lesiones de las estructuras emergentes del FP, como las venas emisarias.

Comparison between the parietal foramina observed in samples of African and European population groups / Comparación entre los forámenes parietales observados en muestras de grupos de población africanos y europeos

SUMMARY: Parietal foramina of the human skull act as a passageway for emissary veins, connecting the superior sagittal sinus to the veins of the scalp. This passageway can lead to the spread of infection from the scalp to the dural venous sinuses, but may also assist in relieving intracranial pressure. However, variation in the prevalence of parietal foramina has been noted among population groups. This observational and descriptive study aimed to determine the incidence, size and location of parietal foramina by using osteological specimens of 252 African skulls from the Sefako Makgatho Health Sciences University, South Africa and 95 European skulls from the University of Leipzig, Germany. Parietal foramina were significantly more common in the African sample (61.9 %) compared to the European sample (55.8 %). Moreover, the Central European sample displayed more unilateral foramina (29.5 %), while the African sample exhibited more bilateral foramina (40.8 %). The diameter of the parietal foramen average 1.98 mm and 1.88 mm for the European and African samples, respectively. In this study, a median foramen on the sagittal suture was observed in 14 of the overall skull caps (4 %). This study demonstrated that parietal foramina are more prevalent than anticipated in both population groups. Findings of this study, indicating an increased prevalence, and the subsequent possibility of more emissary veins encountered, can be used to improve the understanding of the variations in the prevalence and clinical implications of the parietal foramen among various population groups located world-wide.

Los forámenes parietales del cráneo humano actúan como una vía para las venas emisarias, conectando el seno sagital superior con las venas del cuero cabelludo. Este pasaje puede conducir a la propagación de infecciones desde el epicráneo (calva) hasta los senos venosos durales, pero también puede ayudar a aliviar la presión intracraneal. Sin embargo, se ha observado una variación en la prevalencia de los forámenes parietales entre los grupos de población. Este estudio observacional y descriptivo tuvo como objetivo determinar la incidencia, el tamaño y la ubicación de los forámenes parietales mediante el uso de muestras osteológicas de 252 cráneos africanos de la Universidad de Ciencias de la Salud Sefako Makgatho, Sudáfrica, y 95 cráneos europeos de la Universidad de Leipzig, Alemania. Los forámenes parietales fueron significativamente más comunes en la muestra africana (61,9 %) en comparación con la muestra europea (55,8 %). Además, la muestra centroeuropea mostró más forámenes unilaterales (29,5 %), mientras que la muestra africana mostró más forámenes bilaterales (40,8 %). El diámetro del foramen parietal promedió 1,98 mm y 1,88 mm para las muestras europeas y africanas, respectivamente. En este estudio, se observó un foramen medio en la sutura sagital en 14 de los cráneos en general (4 %). El estudio demostró que los forámenes parietales son más frecuentes de lo previsto en ambos grupos de población. Los hallazgos de este estudio, que indican una mayor prevalencia y la subsiguiente posibilidad de que se encuentren más venas emisarias, pueden ser útiles para mejorar la comprensión de las variaciones en la prevalencia y las implicaciones clínicas del foramen parietal entre varios grupos de población ubicados en el mundo.

Anatomy and development of skull-neck boundary structures in the skeleton of the extant crocodylian Alligator mississippiensis.

A system-by-system approach dominates morphological and evolutionary study; however, some structures that are better understood within the context of an interface between two systems or traditional units remain less well understood. As part of a larger goal to clarify aspects of skull-neck boundary evolution, we herein describe the morphology and development of the occiput and atlas-axis complex in the crocodylian Alligator mississippiensis. We apply micro-computed tomography scanning, clearing and double staining, and histological analyses to skull-neck boundary structures at three stages of development (embryonic stage 22, 23, and hatchling). Regions of ossification that could possibly pertain to a postparietal were found adjacent to the parietal bone and supraoccipital; however, these were not deemed convincing and are considered part of the supraoccipital. Within the atlas-axis complex, the proatlas appears as two discrete cartilaginous elements in Stage 22 that ossify together at Stage 23. Posterior to the proatlas, the atlas-axis complex is composed of two centra, each with cervical ribs ventrally and neural arches dorsally that begin ossifying at Stage 23. Histology and clearing and staining of Stages 22 and 23 embryos reveal a discrete atlas intercentrum applied to the ventral part of the occipital condyle of the skull. Posterior to this is a cartilage that appears to be a co-chondrified atlas pleurocentrum, axis intercentrum, and axis pleurocentrum. Ossification of this cartilaginous structure produces discrete atlas inter- and pleurocentra, as well as a singular axis centrum. Together these data are discussed with reference to clarifying historical discrepancies concerning elements at the crocodylian skull-neck boundary.

The morphometric study of parietal emissary foramen related with clinical implications in Thais / Estudio morfométrico del foramen emisario parietal relacionado con las implicaciones clínicas en tailandeses

SUMMARY: Parietal emissary foramina (PEF) are an important structure which the parietal emissary vein passes through. Aims of this study were to study morphometry of the PEF and its clinical implications. The present study examined in 800 parietal bones (400 Thai skulls; 200 males and 200 females). A total of 587 emissary foramina were found in 344 skulls. The PEF were found on the right side (298), left side (256). One hundred fifty-five unilateral, 189 bilateral, and 33 center of PEF were found in our study. The average of foramina to sagittal suture were 5.67 ? 2.73 mm on the right and 5.91 ? 2.37 mm on the left in male, while in female it was 5.28 ? 2.61 mm on the right and 5.48 ? 2.54 mm on the left. The shape was mostly circular with mean diameter of 1.27 ? 0.56 mm on the right, 1.23 ? 0.52 on the left and 1.11 ? 0.49 mm at the center in male. In female, the mean diameter of 1.19 ? 0.42 mm on the right, 1.12 ? 0.41 mm on the left and 1.60 ? 0.92 mm at the center. The ratio of distance from the external occipital protuberance (EOP)to PEF and to glabella in males on the right side is 0.342 cm. (3/8) and 0.349 cm. (3/8) on the left side. While the ratio of females is 0.367 cm. (3/8) and 0.388 cm. (3/8), respectively. Our finding obtained in this study scientists can be essentially benefited for anatomists, radiologists, neurosurgeons, and forensic to aware this anatomical structure.

RESUMEN: El foramen emisario parietal (FEP) es una importante estructura a través de la cual atraviesa la vena emisaria parietal. Los objetivos de este estudio fueron estudiar la morfometría del FEP y sus implicaciones clínicas. Se examinaron 800 huesos parietales (400 cráneos tailandeses pertenecientes a 200 hombres y 200 mujeres). Se encontró un total de 587 FEP en 344 cráneos, de los cuales 298 estaban presentes en el lado derecho y 256 en el lado izquierdo, siendo 155 FEP unilaterales, 189 bilaterales y 33 localizados en el centro. El promedio de la distancia de los FEP a la sutura sagital en los hombres fue de 5,67 ? 2,73 mm a la derecha y 5,91 ? 2,37 mm a la izquierda, mientras que en las mujeres fue de 5,28 ? 2,61 mm a la derecha y 5,48 ? 2,54 mm a la izquierda. La forma era mayoritariamente circular con un diámetro medio de 1,27 ? 0,56 mm en el lado derecho, 1,23 ? 0,52 en el lado izquierdo y 1,11 ? 0,49 mm en el centro en los cráneos de los hombres. En las mujeres, el diámetro medio del FEP en el lado derecho fue de 1,19 ? 0,42 mm, en el lado izquierdo 1,12 ? 0,41 mm 1,60 ? 0,92 mm en el centro. La relación de la distancia desde la protuberan- cia occipital externa al FEP y a la glabela en el lado derecho en los hombres fue de 0,342 cm (3/8) y en el lado izquierdo 0,349 cm (3/8). Mientras en las mujeres fue de 0,367 cm (3/8) y 0,388 cm (3/8), respectivamente. Nuestros hallazgos obtenidos en este estudio puede ser útil para que los anatomistas, radiólogos, neurocirujanos y científicos forenses conozcan esta estructura anatómica.

The character of parietal and orbital alterations in the superfamily Hominoidea (families Hominidae [exclusive of Homo] and Hylobotidae).

Parietal external surface disruption routinely referred to as porotic hyperostosis, and orbital alterations (cribra orbitalia), have been attributed to anemia-related bone marrow hyperplasia in humans. A recent study in humans identified that they were actually vascular in nature. Skeletons were examined and epi-illumination surface microscopy was performed on the parietal region and orbit of 156 Hominidae and 123 Hylobotidae to assess if these phenomena were trans-phylogenetic. Trans-cortical channels were recognized on the basis of visualized ectocranial surface defects penetrating the parietal; cribra orbitalia, by alteration of the normally smooth orbital roof appearance. Trans-cortical parietal channels, ranging in size from 20 to 100 µm, are rare in Gorilla and Pan troglodytes and absent in Pan paniscus. They are universally present in adult Pongo abeli and in Hylobatidae, independent of species. Cribra orbitalia was common in Hylobotidae, Pongo pygmaeus and P. abelii, less prevalent in adult P. troglodytes, and not recognized in any Gorilla gorilla or P. paniscus examined. The proliferative form predominated, with the exception of Hylobates concolor and muelleri, in which uncalcified vascular grooves predominated. No correlation was observed between the presence of either trans-cortical channels or cribra orbitalia and fractures, osteoarthritis, or inflammatory arthritis. Parietal alterations observed in apes are trans-cortical channels, analogous to those observed in humans, and do not represent porosity. Similarly, cribra orbitalia in apes is confirmed as vascular in nature. The proliferative form apparently represents calcification of blood vessel walls, indistinguishable from observations in humans. Predominant presence in adults rather than in juveniles suggests that both forms are acquired rather than developmental in derivation. Sex and bone alteration/disease-independence suggests that mechanical, endocrine, and inflammatory phenomena do not contribute to the development of either. Further, independent occurrence of trans-cortical channels and cribra orbitalia suggests that they do not have a shared etiology.

Stress and strain propagation on infant skull from impact loads during falls: a finite element analysis.

Background and Objective: To simulate infant skull trauma after low height falls when variable degrees of ossification of the sutures are present. Methods: A finite elements model of a four-week-old infant skull was developed for simulating low height impact from 30 cm and 50 cm falls. Two impacts were simulated: An occipito-parietal impact on the lambdoid suture and a lateral impact on the right parietal and six cases were considered: unossified and fully ossified sutures, and sagittal, metopic, right lambdoid and right coronal craniosynostosis. Results: 26 simulations were performed. Results showed a marked increase in strain magnitudes in skulls with unossified sutures and fontanels. Higher deformations and lower Von Mises stress in the brain were found in occipital impacts. Fully ossified skulls showed less overall deformation and lower Von Mises stress in the brain. Results suggest that neonate skull impact when falling backward has a higher probability of resulting in permanent damage. Conclusion: This work shows an initial approximation to the mechanisms underlying TBI in neonates when exposed to low height falls common in household environments, and could be used as a starting point in the design and development of cranial orthoses and protective devices for preventing or mitigating TBI.

Potential donor sites of the parietal for bone grafting and its relationship to the cephalic index / Sitios donantes potenciales del hueso parietal para injerto óseo y su relación con el índice cefálico

The purpose of the present study was to chart the thickness of the parietal bone and establish its relationship with the cephalic index and sex aiming at improving current knowledge and guidance for obtaining calvarial bone auto-graft material. Both left and right parietal bones of 150 skulls of adult human cadavers classified as either dolicho-, meso-, or brachicephalic, and as either male or female had their thickness measured at 3 levels ­ superior (S), middle (M) and inferior (I) ­ and at 3 points ­ anterior (a), middle (m) and posterior (p) ­ in each level, all evenly laid out. No relevant differences in thickness whether comparing sex or cephalic index was evidenced. The thickest measurements were found at points located at superior and middle levels in middle and posterior positioning ­ Sm, Sp, Mm and Mp ­ with median values ranging from about 5.5mm to 7.13mm. At inferior level and posterior positioning, thickness median values ranged from 4.71 to 5.84mm. Safer harvesting of bone graft material occurs in Sm, Sp, Mm and Mp areas of the parietal bone. Only exceptionally should Ip domain be used, whereas Sa, Ia and Im regions should be considered non-donor sites.

El propósito del estudio fue medir el grosor del hueso parietal y establecer su relación con el índice cefálico y el sexo, con el objetivo de mejorar el conocimiento actual y la orientación para el auto-injerto de material óseo. Fueron estudiados huesos parietales, tanto izquierdos como derechos, de 150 cráneos de cadáveres humanos adultos, de hombres y mujeres, clasificados como dolico-, meso- o braquicefálico; el espesor fue medido en 3 niveles: superior (S), medio (M) e inferior (I) - y en 3 puntos - anterior (a), medio (m) y posterior (p) - en cada nivel, todas uniformemente establecidas. No se observaron diferencias relevantes en el grosor a nivelrespecto del sexo o el índice cefálico. Las mediciones más gruesas se encontraron en los puntos situados en los niveles superior y medio, y en posiciones medias y posteriores - Sm, Sp, Mm y Mp - con valores medianos que oscilaban entre aproximadamente 5,5 mm y 7,13 mm. En el nivel inferior y posicionado posterior, los valores medianos del espesor oscilaron entre 4,71 y 5,84 mm. La recolección más segura del material de injerto óseo ocurre en las áreas Sm, Sp, Mm y Mp del hueso parietal. Sólo excepcionalmente se debe utilizar el dominio Ip, mientras que las regiones Sa, Ia e Im deben considerarse sitios no donantes.

A Macro-Anatomical Investigation of the Some Skull Bones of Nehring's Blind Mole Rats (Spalacidae: Nannospalax nehringi).

This study was aimed to demonstrate the specific anatomical features of the skull bones of Nehring's blind mole rats. Eight skulls, belonging to animals of both sexes, were used. The occipital squama contributed to the formation of the caudal portion of the skull roof. The foramen magnum was quite large. The external occipital crest was present only in the males. The parietal bones formed the middle portion of the skull roof together with the well-developed inter-parietal bones. The zygomatic process of the temporal bone formed the zygomatic arch by extending to the temporal process of the zygomatic bone. The zygomatic process of the frontal bone and the frontal process of the zygomatic bone laterally bordered the orbit. There was a single septal process of the nasal bone. Each ramus of the mandibula had four processes. The mandibular ramus had an angular process on its caudal rim, which extended dorsolaterally. The dorsal free end of the mandibular ramus possessed a coronoid process. In the back, there were two other processes, situated medially and laterally. The medially situated process was referred to as a condylar process, and the laterally situated process was referred to as an alveolar process. The alveolar process detected on the mandibular ramus has not been reported in any rodent species, other than those of the family Spalacidae. Blind mole rats can be a real eye-opener for evolutionary science. The burrowing rodents are key to answering a controversial question about how new species arise.

Effect of Wnt3a delivery on early healing events during guided bone regeneration.

OBJECTIVE: To evaluate the effect of recombinant Wnt3a delivery on the bone regeneration potential following application of the guided bone regeneration (GBR) principle. MATERIALS AND METHODS: A critical-size calvarial defect was created on each parietal bone of 14 Wistar strain rats. One defect was used as the test side and was treated with a collagen sponge carrying 2.0 µg of recombinant Wnt3a protein, whereas the contralateral side served as sham-operated control. Both defects were covered at both the extracranial and intracranial aspects with ePTFE non-resorbable membranes, according to the GBR principle. Following healing periods of 4 and 7 days, qualitative histological and histomorphometric evaluation of undecalcified sections was performed in subgroups of seven animals. The primary outcome parameter was the mean percentage of defect closure in the test and control defects. RESULTS: At 4 days of healing, a network of coagulum and fibrin was observed and initial signs of granulation tissue formation were evident with no apparent differences between the test and control groups. At 7 days of healing, the test group presented newly formed woven bone, originating from the borders of the defect, as opposed to the control group, whereby woven bone formation was not observed in any of the specimens. CONCLUSIONS: The delivery of mouse recombinant Wnt-3a protein in combination with GBR may promote woven bone formation in critical-size calvarial defects at 7 days of healing.

Parietal Bone Thickness and Vascular Diameters in Adult Modern Humans: A Survey on Cranial Remains.

Cranial bone thickness varies among modern humans, and many factors influencing this variability remain unclear. Growth hormones and physical activity are thought to influence the vault thickness. Considering that both systemic factors and energy supply influence the vascular system, and taking into account the structural and biomechanical interaction between endocranial vessels and vault bones, in this study we evaluate the correlation between vascular and bone diameters. In particular, we tested the relationship between the thickness of the parietal bone (which is characterized, in modern humans, by a complex vascular network) and the lumen size of the middle meningeal and diploic vessels, in adult modern humans. Our results show no patent correlation between the thickness of parietal bone and the size of the main vascular channels. Values and distributions of the branching patterns, as well as anatomical relationships between vessels and bones, are also described in order to provide information concerning the arrangement of the endocranial vascular morphology. This information is relevant in both evolutionary and medical contexts. Anat Rec, 299:888-896, 2016. © 2016 Wiley Periodicals, Inc.

Os parietale partitum: Exploring the prevalence of this trait in four contemporary populations.

Os parietale partitum is a variable segmentation of the parietal bone. This manifests as a parietal division in the anteroposterior or superoinferior planes that is separated by an unusual suture and can be complete or incomplete. The existence of parietal divisions was observed and documented more than 260 years ago. The main objectives of this paper are to record the incidence of this rare trait in four modern populations with no previous records of it and provide a review of the literature. Four contemporary skeletal collections from Crete (Greece), Limassol (Cyprus), Coimbra (Portugal) and Salvador (Brazil) were assessed by the authors of this paper for non-metric cranial traits. Out of 711 skulls, only three cases of parietal division were found and all three originated from the Cypriot collection. These three cases were anatomically analyzed, showing that all three cases were adult females and showed unilateral expression of the trait. Two skulls showed superoinferior division, and the third case showed anteroposterior division. Numerous other cranial non-metric traits were found in these three skulls. Based on the cemetery archives, there seems to be no genetic link between the individuals bearing this trait. Further genetic analysis is suggested in order to verify this conclusion.

Pediatric Orbital Depth and Growth: A Radiographic Analysis.

BACKGROUND: Orbital reconstruction requires knowledge of orbital depth in order to prevent optic nerve injury. Numerous analyses of adult orbital dimensions have been undertaken previously in order to characterize this measurement, including skull specimen and computerized tomography studies. However, there is a paucity of information regarding the pediatric orbit. METHODS: The authors used pediatric magnetic resonance imaging (MRI) studies in order to quantify the change in orbital depth in relationship to patient age, and to develop methods to estimate and calculate orbital depth for individual pediatric patients. MRIs of the head in normal pediatric patients were reviewed retrospectively. Orbital depths were measured and correlated with age and cephalometric dimensions. In a randomly selected subgroup of patients, measurements were repeated by an independent investigator to determine interobserver reliability. RESULTS: Measurements were obtained in 72 patients ranging from 3 months to 18 years of age (mean=7.8 years). There was a significant exponential relationship between orbital depth and patient age (r=0.81, F(2,69)=143.97, P<0.001). Depth increased more rapidly in the first 6 years of life, but leveled off in the early teen years toward a horizontal asymptote of approximately 45 mm. There was also a significant relationship between orbital depth and the sum of the biparietal width plus the anterior-posterior length (r=0.72, F(2,69)=87.44, P<0.0001). There was high interobserver reliability in measurements between 2 independent investigators (r=0.79, P<0.0001). CONCLUSION: In children, orbital depth increases predictably with rising age and increasing head size. Knowledge of this growth curve and the relationship between head size and orbital depth can complement careful surgical dissection to improve safety and efficacy in pediatric orbital reconstructions.

Frontoparietal Bone in Extinct Palaeobatrachidae (Anura): Its Variation and Taxonomic Value.

Palaeobatrachidae are extinct frogs from Europe closely related to the Gondwanan Pipidae, which includes Xenopus. Their frontoparietal is a distinctive skeletal element which has served as a basis for establishing the genus Albionbatrachus. Because little was known about developmental and individual variation of the frontoparietal, and its usefulness in delimiting genera and species has sometimes been doubted, we investigate its structure in Palaeobatrachus and Albionbatrachus by means of X-ray high resolution computer tomography (micro-CT). To infer the scope of variation present in the fossil specimens, we also examined developmental and interspecific variation in extant Xenopus. In adults of extinct taxa, the internal structure of the frontoparietal bone consists of a superficial and a basal layer of compact bone, with a middle layer of cancellous bone between them, much as in early amphibians. In Albionbatrachus, the layer of cancellous bone, consisting of small and large cavities, was connected with the dorsal, sculptured surface of the bone by a system of narrow canals; in Palaeobatrachus, the layer of cancellous bone and the canals connecting this layer with the dorsal surface of the frontoparietal were reduced. The situation in Palaeobatrachus robustus from the lower Miocene of France is intermediate-while external features support assignment to Palaeobatrachus, the inner structure is similar to that in Albionbatrachus. It may be hypothesized that sculptured frontoparietals with a well-developed layer of cancellous (i.e., vascularized) bone may indicate adaptation to a more terrestrial way of life, whereas a reduced cancellous layer might indicate a permanent water dweller.

The brain and the braincase: a spatial analysis on the midsagittal profile in adult humans.

The spatial relationships between brain and braincase represent a major topic in surgery and evolutionary neuroanatomy. In paleoneurology, neurocranial landmarks are often used as references for brain areas. In this study, we analyze the variation and covariation of midsagittal brain and skull coordinates in a sample of adult modern humans in order to demonstrate spatial associations between hard and soft tissues. The correlation between parietal lobe size and parietal bone size is very low, and there is a marked individual variation. The distances between lobes and bones are partially influenced by the dimensions of the parietal lobes. The main pattern of morphological variability among individuals, associated with the size of the precuneus, apparently does not influence the position of the neurocranial sutures. Therefore, variations in precuneal size modify the distance between the paracentral lobule and bregma, and between the parietal lobe and lambda. Hence, the relative position of the cranial and cerebral landmarks can change as a function of the parietal dimensions. The slight correlation and covariation among these elements suggests a limited degree of spatial integration between soft and hard tissues. Therefore, although the brain influences the cranial size and shape during morphogenesis, the specific position of the cerebral components is sensitive to multiple effects and local factors, without a strict correspondence with the bone landmarks. This absence of correspondent change between brain and skull boundaries suggests caution when making inferences about the brain areas from the position of the cranial sutures. The fact that spatial relationships between cranial and brain areas may vary according to brain proportions must be considered in paleoneurology, when brain anatomy is inferred from cranial evidence.

The Incidence and Topographic Distribution of Sutures Including Wormian Bones in Human Skulls.

OBJECTIVE: The Wormian Bones are accessory bones located within the cranial sutures and fontanelles. The present article examines the incidence of Wormian Bones and compares the number and topographic distribution between the sutures including Wormian Bones in skulls of West Anatolian Population. METHODS: One hundred fifty crania were examined. The parameters evaluated in the present study were as follows: the rate of skulls including Wormian Bones; the topographic distribution and frequencies of the sutures including Wormian Bones; the number of these sutures for each skull; the name and number of sutures that were bilaterally and symmetrically located on the right and left side of skull (paired sutures) and which coincidentally had Wormian Bones for each skull; the differences of frequencies between the paired sutures including Wormian Bones. RESULTS: The rate of skulls including Wormian Bones was determined as 59.3%. The maximum and minimum numbers of sutures, including Wormian Bones, were 6 in 1 skull and 1 in each of 30 skulls, respectively. The maximum and minimum rates of sutures that had Wormian Bones were found in left lambdoid 40.7% and right occipitomastoid 1.3% sutures, respectively. There was only a significant difference between the rate of right and left squamous sutures (P = 0.04). Forty-five skulls were including 55 pairs of bilaterally and symmetrically located sutures that coincidentally had Wormian Bones in each pair. Each of 35 skulls had 1 pair of sutures including Wormian Bones and each of 10 skulls had 2 pairs. CONCLUSIONS: In the present study, the rate of Wormian Bones was determined as 59.3% in West Anatolian Population. This incidence rate is considerably lower than the other reports, and it may be as a result of racial variations. These divergent bones were more frequently found in left lambdoid sutures (40.7%) and less frequently in right occipitomastoid sutures (1.3%). This study may guide the investigators dealing with the neurosurgery, orthopedy, radiology, anatomy, and anthropology in their practice.

Differences in biomechanical properties and thickness among frontal and parietal bones in a Japanese sample.

The aim of this study was to assess the mechanical properties and thickness of adult frontal and parietal bones. The heads of 114 Japanese cadavers (78 male cadavers and 36 female cadavers) of known age and sex were used. A total of 912 cranial samples, 8 from each skull, were collected. Samples were imaged using multidetector computed tomography to measure sample thickness. The fracture load of each sample was measured using a bending test with calculation of flexural strength. Statistical analyses demonstrated no significant bilateral difference in either the mechanical properties or thickness of frontal or parietal bones. The mechanical properties and thicknesses of frontal bones were significantly greater than those of parietal bones regardless of sex. Therefore, the skull may have a great ability to resist frontal impacts compared with parietal impacts. In female samples, parietal bones were found to have a more uniform structure when compared with male samples. Male parietal bones were found to be thicker at medial sites than at lateral sites. This study also revealed parietal bones at lateral sites in female samples were thicker than in male samples. No strong association was observed between age and flexural strength of frontal or parietal bones. However, the fracture load was negatively correlated with age most likely due to the reduction of thickness.

Homo erectus in Salkhit, Mongolia?

In 2006, a skullcap was discovered in Salkhit, Mongolia. The Salkhit skullcap has a mostly complete frontal, two partially complete parietals, and nasals. No chronometric dating has been published yet, and suggested dates range from early Middle Pleistocene to terminal Late Pleistocene. While no chronometric date has been published, the presence of archaic features has led to a potential affiliation with archaic hominin species. If it is indeed Homo erectus or archaic Homo sapiens, Salkhit implies a much earlier spread of hominins farther north and inland Asia than previously thought. In this paper, the nature of the archaic features in Salkhit is investigated. The Salkhit skullcap morphology and metrics were compared with Middle and Late Pleistocene hominin fossils from northeast Asia: Zhoukoudian Locality 1, Dali, and Zhoukoudian Upper Cave. Results show an interesting pattern: on one hand, the archaic features that Salkhit shares with the Zhoukoudian Locality 1 sample also are shared with other later hominins; on the other hand, Salkhit is different from the Middle Pleistocene materials in the same way later hominins differ from the Middle Pleistocene sample, in having a broader frontal and thinner supraorbital region. This may reflect encephalization and gracilization, a modernization trend found in many places. It is concluded that the archaic features observed in Salkhit are regionally predominant features rather than diagnostic features of an archaic species.

Stereotaxis of mandibular nerve initial point of trigeminal ganglion in rats.

OBJECTIVE: To acquire parameters for stereotaxis of the mandibular nerve initial point of the trigemenial ganglion (TG) and to test the accuracy of the acquired parameters for microinjection into the mandibular nerve initial point of TG in adult rats. METHODS: Sprague-Dawley rats (260-270 g) were mounted onto a stereotaxic frame. The bregma was set as an anchor point and the three-dimensional parameters between the mandibular nerve initial point of the bilateral TGs and the bregma were measured in 25 rats. The accuracy of these parameters was tested using microinjection of Evans blue dye into the mandibular nerve initial point of the bilateral TGs in 30 rats and the injection sites were evaluated by dissection. RESULTS: The three-dimensional parameters of the mandibular nerve initial point of the bilateral TGs were 3.5 ± 0.1 mm posterior and 3.6 ± 0.2 mm lateral to the bregma, and 12.0 ± 0.2 mm inferior to the skull surface. Accuracy for the microinjection of Evans blue dye into the mandibular nerve initial point of the bilateral TGs was 86.7% (52/60). CONCLUSION: The acquired parameters served well for stereotaxis and microinjection of reagents into the mandibular nerve initial point of TG.

[Clinico-morphological substantiation of feasibility of angiosomic adipose-cutaneous flaps from temporal and parietal regions application].

Actuality of the problem, consisting of restoration of defects and deformity zones on head and neck, is caused by great quantity of patients, surgical treatment of which constitute important medico-social problem. The flaps, raised from temporal and parietal regions, are considered perspective for replacement of defects and the deformity zones on head and neck. But, for their correct isolation and mobilization it is necessary to know the topographoanatomical peculiarities of superficial temporal artery, localization of which differs, depending on the head form. The methods of isolation and mobilization of angiosomic preauricular, postauricular and fascial temporal-parietal flaps were optimized in the clinic, basing on analysis of results of the investigations performed and computeric modeling of the superficial temporal artery branches.