Fractality of Cranial Sutures.

It has long been known that skull suture has a typical fractal structure. Although the fractal dimension has been utilized to assess morphology, the mechanism of the fractal structure formation remains to be elucidated. Recent advances in the mathematical modeling of biological pattern formation provided useful frameworks for understanding this mechanism. This chapter describes how various proposed mechanisms tried to explain the formation of fractal structures in cranial sutures.

Wormian Bones: Prevalence, Topography, and Implications.

BACKGROUND: Wormian bones also known as sutural bones are asymmetrical and shapeless bones occurring in cranial sutures and fontanelle of the skull. Their incidence is reported to vary in population. The exact etiology is debatable, but their formation is under the control of both genetic and environmental factors and has great anthropological and clinical implications related to the cranium. Due to high clinical relevance of Wormian bones, the study was carried out. The aim of the study is to expound the incidence and topography of Wormian bones along with clinical significance in dry adult skulls of Indian origin. METHODS: The study was conducted in the Department of Anatomy using 200 complete adult dry skulls of unknown age and sex. All the sutures in the skull were inspected for the presence of Wormian bones. The Wormian bones were classified into 10 categories, and associated implications were brought out. The Wormian bones were photographed, and details were compared with the available literature. RESULTS: The Wormian bones were observed in 190 (380 sides) skulls with 186 on the right side and 108 on the left side. The predominance site of sutural bone was lambdoid suture followed by sagittal suture. The least common site of Wormian bone was lambda. CONCLUSION: The detailed information of precise topography, frequency, and number of Wormian bones is of utmost use for surgeons performing surgery on the skull, anthropologists for identifying races, and forensic scientists for investigating child abuse cases.

Comparative digital reconstruction of Pica pica and Struthio camelus and their cranial suture ontogenies.

To date, several studies describe post-hatching ontogenetic variation in birds; however, none of these studies document and compare ontogenetic variation of the entire skull in multiple avian species. Therefore, we studied ontogenetic skull variation of two bird species with very different ecologies, Pica pica, and Struthio camelus, using µCT based 3D reconstructions. For each specimen, we performed bone-by-bone segmentation in order to visualize and describe the morphological variation of each bone during ontogeny and estimated the average sutural closure of the skulls to identify different ontogenetic stages. Although bone fusion of P. pica occurs more rapidly than that of S. camelus the general sequence of bone fusion follows a similar trend from posterior to anterior, but a more detailed analysis reveals some interspecific variation in the fusion patterns. Although growth persists over a longer period in S. camelus than in P. pica and adults of the former species are significantly larger, the skull of the most mature S. camelus is still less fused than that of P. pica. Different growth and fusion patterns of the two species indicate that the interspecific ontogenetic variation could be related to heterochronic developments. Nevertheless, this hypothesis needs to be tested in a broader phylogenetic framework in order to detect the evolutionary direction of the potential heterochronic transformations.

Analysis of the Asterion Morphology in Relation to Its Clinical Significance / Análisis de la Morfología del Asterion en Relación con su Importancia Clínica

SUMMARY: The asterion presents a significant anthropological marking and meeting point between three sutures. It is a surface landmark for the transverse-sigmoid venous sinus complex and is also a surgical landmark for access to the posterior cranial fossa, giving it clinical importance. The aim of this research was to analyze the shape of the asterion and to set the measurement methods that will determine distance between the asterion and surrounding features. The study sample, as a part of the Osteological collection of the Department of Anatomy, Faculty of Medicine Novi Sad, consisted of 43 skulls. Morphometric analysis was related to the measurement of the defined parameters and descriptive analysis presented the classification of asterion in relation to the presence of sutural bones, as well as the determination of the position of the asterion according to the transverse-sigmoid venous complex. There was a statistically significant difference between male and female skulls for all the measured parameters. The results show that 34.88 % were type 1 (one or more sutural bones are present) and 65.12 % were type 2 asteria (no sutural bones are present). More frequent occurrence of asteria type 2 was seen on both, male and female skulls. The most frequent position of the asteria on both sides of the skull was in the transverse- sigmoid venous complex (76.92 % on the right side vs. 72.22 % on the left cranial side). Clinical significance of knowing the area of asterion is reflected in order to make the surgical, as well as diagnostic procedures, as successful as possible.

El asterion presenta una importante marca antropológica y punto de encuentro entre tres suturas. Es un punto de referencia de superficie para el complejo del seno venoso sigmoideo transverso y también es un punto de referencia quirúrgico para el acceso a la fosa craneal posterior, lo que le confiere importancia clínica. El objetivo de esta investigación fue analizar la forma del asterión y establecer los métodos de medición que determinarán la distancia entre el asterión y las características circundantes. La muestra del estudio, que forma parte de la colección osteológica del Departamento de Anatomía de la Facultad de Medicina de Novi Sad, estuvo compuesta por 43 cráneos. El análisis morfométrico se relacionó con la medición de los parámetros definidos y el análisis descriptivo presentó la clasificación del asterion en relación a la presencia de huesos suturales, así como la determinación de la posición del asterion según el complejo venoso transverso-sigmoideo. Hubo una diferencia estadísticamente significativa entre los cráneos masculinos y femeninos para todos los parámetros medidos. Los resultados muestran que el 34,88 % eran tipo 1 (hay uno o más huesos suturales presentes) y el 65,12 % eran asteria tipo 2 (no hay huesos suturales presentes). Se observó una aparición más frecuente de asteria tipo 2 en cráneos tanto masculinos como femeninos. La posición más frecuente de la asteria en ambos lados del cráneo fue en el complejo venoso sigmoideo transverso (76,92 % en el lado derecho vs. 72,22 % en el lado craneal izquierdo). La importancia clínica de conocer el área de asterion se refleja en que los procedimientos quirúrgicos y de diagnóstico tengan el mejor resultado posible.

Is Asterion a Reliable Surgical Landmark for the Transverse and Sigmoid Sinus Junction in Indian Skulls?

Background: Asterion is the junction of lambdoid, parietomastoid, and occipitomastoid sutures. In traditional anatomy teaching, it is believed that asterion sits over the transverse-sigmoid sinus junction (TSSJ). It is a significant surgical landmark for the placement of a burr hole in the retrosigmoid approach. Objective: The purpose of this study was to evaluate the asterion's accuracy as a TSSJ-specific external surgical landmark in the Indian population. Materials and Methods: 16 human dried skulls were obtained from the Department of Anatomy, AIIMS, New Delhi. The point of TSSJ was taken between the two lips and just posterior to the entry of the superior petrosal sinus. Asterion internally was localized with the help of a geometrical divider. The x- horizontal/ anterior and y- vertically superior (+)/ inferior (-) distances were measured from asterion (internally) to the TSSJ by a digital vernier caliper. Results: The mean horizontal distance (x) of the left side asterion & TSSJ was 10.3±1.0mm whereas the vertical distance (y) ranged between +2 to -4.3 mm. The mean horizontal distance (x) of the right side asterion & TSSJ was 13.5±1.4mm whereas the vertical distance (y) ranged between +3 to -4.2 mm. Conclusion: Asterion is not a reliable landmark for TSSJ in Indian skulls. The TSSJ with respect to asterion was found on average 10mm and 13.5mm anterior on the left and right side respectively, and mostly inferior (average 4.2mm) in 75% of the skulls. The TSSJ was closer to the asterion on the left side in comparison with the right side. However, further studies with a larger sample size will be needed to evaluate the population-specific relation of asterion with the TSSJ.

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.

Frequency Morphologic and Morphometric Properties and Osseous Relationships of Whitnall's Tubercle.

Whitnall tubercle (WT) of the zygomatic bone is used as an anatomical landmark in some surgical approaches to the orbit. The authors aimed to determine the localization of WT by using some palpable bony landmarks and to reveal its morphological and morphometric features. Three hundred twenty-two zygomatic bones (167 right and 155 left) belonging to adults of unknown sex, were examined. An acetate prepared by drawing a clock with a dial on it was used to determine the localization of WT according to marginal tubercle and zygomatic arch. Distances between WT and frontozygomatic suture and lateral margin of the orbital rim were measured with digital calipers. One zygomatic bone had double tubercles, thus 321 bones were taken into consideration. Whitnall tubercle was determined in 284 of 321 zygomatic bones. 181 were classified as small, 10 as medium, and 93 as large. The position of the WT according to the marginal tubercle was at the 8, 9, and 10 o'clock positions on the left, and at 2, 3, and 4 o'clock on the right. The position of the WT according to the zygomatic arch was at the 9,10 and 11 o'clock positions on the left, and at the 1 and 2 o'clock positions on the right. Distances between the WT and lateral margin of the orbital rim and the frontozygomatic suture were measured meanly as 1.94±0.31 mm and 8.17±5.82 mm, respectively. The authors believe that the data obtained regarding WT will contribute to anatomy and surgical procedures of the related region.

Age estimation by palatal suture using modified Kamijo's method.

The present study aimed to investigate the correlation between palatal suture obliteration and age in modern Japanese and to develop an age estimation equation by modifying Kamijo's (1949) method. The subjects were 195 Japanese skeletal remains (155 males and 40 females) whose age and sex were known. First, obliteration score (OS) was obtained by measuring palatal suture obliteration from photographic images taken at the time of forensic autopsy, and the correlation with age was examined; no significant correlation was found in females. Second, the palatal sutures were divided into 14 sections, and each section was scored from 0 to 4 points according to the degree of the suture obliteration. Suture scores (SS) were then calculated for each of the four sutures, and the sum of the 14 scores (TSS: total suture score) was used to perform regression analysis for age. For male and all subjects (male and female), age significantly increased (p < 0.001) according to increment of SSs for all sutures. TSS has the highest regression coefficient (r = 0.540), and the lowest standard error of estimation (13.54 years) for all of the patients. The intra- and inter-observer agreement scoring showed high reliability. Validation study using the formulae showed a high percentage of correct responses (80 %). In conclusion, age estimation regression formula by palatal suture using modified Kamijo's method was established for Japanese population, and the study showed the formula might be valid for age estimation.

Anatomical characteristics and significance of the metopism and Wormian bones in dry adult-Chinese skulls.

BACKGROUND: This study aimed to investigate the incidence, topographical distribution, morphology, and interrelationship of the metopism and Wormian bones (WBs) in dry adult-Chinese skulls. MATERIALS AND METHODS: In this study, 285 dried adult-Chinese skull specimens from the Department of Anatomy at the Southern Medical University were examined. The incidence of different types of metopism and WBs were recorded. The length of the metopic suture was measured using a flexible ruler. Additionally, the lengths and widths of the WBs were measured using a vernier calliper. RESULTS: The incidence of metopism and WBs in Chinese adults were estimated at 10.18% (29/285) and 63.86% (182/285), respectively. The metopism always accompanied WBs (26/29, 89.66%), but the WBs did not necessarily accompany metopism (26/182, 14.29%). The locations of the WBs in the order of decreasing incidence were the lambdoid suture (78.57%, 143/182), pterion (34.62%, 63/182), asterion (12.09%, 22/182), lambda (8.24%, 15/182), sagittal suture (4.95%, 9/182), and Inca bone (3.85%, 7/182). These locations differed in topographical distribution and morphological patterns. CONCLUSIONS: Chinese adults differ in incidence of metopism and WBs from adults of other races, indicating racial differences. The characteristics of WBs vary depending on the cranial site of occurrence. The metopism always accompanies WBs, but the WBs do not necessarily accompany metopism.

Anatomical study of a human skull with multiple osteomas in a seventeenth-century Dutch still-life painting: bone morphology and artistic intention.

Skulls were frequently depicted in seventeenth-century Dutch still-life paintings. Skulls were interpreted as symbols of vanitas-meaning the evanescence of life-but their morphological features have received little attention. This study analyzed a skull with abnormal tumors in a seventeenth-century Dutch still-life painting by a renowned artist, Edwaert Collier (ca. 1642-1708), from anatomical, forensic, and pathological perspectives. The morphology of the cranium and teeth indicated that the skull likely belonged to a middle-aged female. We carefully diagnosed the abnormal masses as multiple osteomas on the skull and left femur, based on clinical studies and paleopathological literature, which reported lesions with a similar appearance to those observed in Collier's work. Furthermore, detailed observations of the cranial sutures and epiphyses of the long bones in his paintings revealed that the artist may have selected bones with a morphology that was suitable for the subject of vanitas. Collier repeatedly depicted the skull with metopism, the rare condition of having a persistent metopic suture in adulthood. A skull with a metopic suture is called Kreuzschädel, meaning the cross skull, because it forms a cruciform by connecting with the sagittal and coronal sutures. The artist might have chosen skulls with metopic sutures, which is reminiscent of the crucifixion of Christ, as an appropriate motif for the vanitas painting. This paper argues that anatomical analysis could explain the hidden meaning of the painting and disclose the fascinating collaborations between anatomy and art in the seventeenth-century Dutch Republic.

Morphometric and morphological evaluation of temporozygomatic suture anatomy in dry adult human skulls.

This study aims to evaluate the position, morphometric, and morphological features of the temporozygomatic suture (TZS) located on the zygomatic arch (ZA) in dry adult human skulls. Thirty-two crania were evaluated. Measurements for the TZS were carried out using the ImageJ software. Morphometric measurements were carried out bilaterally in 23 crania and unilaterally in 9 crania (right: 4, left: 5). A total of 55 TZSs were analyzed. Localization of the TZS was determined according to the reference landmarks on the ZA. Morphologic features of the TZS evaluated in terms of "joint shape type" and "suture margin pattern". Descriptive statistics of the morphometric and morphologic variables were calculated. A statistically significant difference between the right and left sides was observed for the localization of the TZS (p < 0.05). TZS is located more anteriorly on the left side than the right side. Based on the "joint shape type", four types of TZS were observed: Type 1 (angular) (34.55%), Type 2 (curvy) (34.55%), Type 3 (oblique) (14.55%), Type 4 (horizontal) (16.36%). Based on the "suture margin pattern", five types of TZS were observed: Type A (linear) (12.73%), Type B (denticulate) (34.55%), Type C (serrated) (23.64%), Type D (mixt) (21.82%), Type E (fused) (7.27%). No significant association between the type and lateralization was found for both morphologic classifications. To the best of our knowledge, this is the first published report regarding the localization and morphologic classification of the TZS in adult human crania. Considering the TZS with its morphometric and morphological features may contribute to clinical or forensic medical evaluations.

Estimating the Person-Specific Location of Pterion Based on Cranial Morphometry.

OBJECTIVE: Due to being the weakest sutural junction of the crania and relations with intracranial anatomical structures, the accurate location of the pterion is important for surgical approaches such as in pterional craniotomy. The aim of the study was to develop regression equations to estimate the person-specific accurate location of the pterion based on the cranial morphometry. MATERIALS AND METHODS: The study was conducted on 22 pterions located 11 dry skulls belonging to Anatomy Department of the Harran University, Medical Faculty. Twelve parameters related to pterion and 23 parameters related to the skull was measured using ImageJ software. SPSS 20.0 was performed for statistical analyses such as descriptive and comparative statistics and developing regression equations. RESULTS: Statistically significant difference wasn't observed between right and left sides. The 12 equations, such as P8:distance between pterion and the tip of the mastoid process= 63,780 + (1,366 × K6) - (2,786 × K7) + (1,342 × K11) - (1,029 × K13) + (2,102 × K14) - (1,710 × K15) - (0,517 × 22) Adjusted R2= 0.995 and Standard Errors = 1.221 were developed to estimate the accurate location of the pterion based on the cranial morphometry. CONCLUSIONS: In the previous studies, the mean distances of the pterion to certain landmarks on the crania were given. The authors developed formulas in order to estimate the accurate person-specific location of the pterion. The authors are convinced that the equations they have developed will help neurosurgeons in terms of surgical approaches.

Cranial morphology in metopism: A comparative geometric morphometric study.

BACKGROUND: Cranial sutures are active bone growth sites and any alteration in their normal formation, patency and closure influences the overall cranial morphology. This comparative study aims to establish whether the cranial shape and size are significantly modified when metopic suture persists into adulthood using geometric morphometric analyses. METHODS: The sample consisted of 63 metopic and 184 non-metopic dry adult male crania. Three-dimensional polygonal models of the crania were generated using a hand-held laser scanner Creaform VIUscan. A total of 50 landmarks were digitized on the three-dimensional models and eight landmark configurations delineating the cranium and its compartments were constructed and analyzed. Geometric morphometric analyses were applied to investigate separately the size and shape differences between the metopic and non-metopic series in each of the landmark configurations. RESULTS: Significant size differences were established solely in the neurocranium, but not in its total size, rather in its parts. The size modification was expressed by an enlargement of the anterior part of the neurocranium at the expense of the middle and posterior ones. All investigated landmark sets differed significantly between the series regarding the shape. In metopic series, the shape alteration was mainly in a mediolateral widening and an anteroposterior shortening contributing to a more rounded overall shape of the cranium. CONCLUSIONS: The slight modification of the cranial morphology in metopism suggests that the metopic suture persistence is not an isolated variation limited to the frontal bone. It is rather a complex condition associated with a combination of specific phenotypic characteristics.

Anatomical observation and significance of the parietal foramen in Chinese adults.

BACKGROUND: This study aimed to investigate the incidence, number, diameter, and relative location of the parietal foramen (PF) as well as communication of intracranial and extracranial orifices and their direction, and sagittal suture morphology and length. MATERIALS AND METHODS: A total of 280 dry Chinese adult skull specimens from the Department of Anatomy, Southern Medical University, were observed and measured. The occurrence rate and quantity of the PF near the sagittal suture were recorded. The aperture of the PF, the vertical distance between PF and sagittal suture, and the linear distance between PF and lambda were measured using a Vernier calliper. The length of the sagittal suture was measured by a flexible ruler; the direction and communication of intracranial and extracranial orifices were detected using a probe. RESULTS: The total incidence of the PF was 82.86%, slightly higher on the right side than on the left side. The single-foramen type was the most prevalent. The mean diameter of the PF on the left and right sides were 1.02 ± 0.72 mm and 1.07 ± 0.67 mm, respectively, and the diameter of the PF on the sagittal suture was 1.77 ± 0.44 mm. The mean vertical distance between the PF and the sagittal suture was 5.90 ± 2.78 mm and 5.85 ± 2.75 mm on the left and right sides, respectively. The shape of the sagittal suture in the PF area was primarily dentate shaped, with an average arc length of χ = 124.36 ± 7.76 mm, of which the majority were completely healed type. The intracranial and extracranial communication was 39.97%, and the majority of the PF were anteromedial direction. CONCLUSIONS: The current study provided an anatomical basis for imaging diagnosis and neurosurgery by investigating the incidence, diameter, and relative location of the PF and intracranial and extracranial communication and direction.

Anatomic position of the asterion and implication for neurosurgical procedure / Posición anatómica del asterion y sus implicancias en el procedimiento neuroquirúrgico

SUMMARY: The asterion is the joining of the lambdoid, parietomastoid, and occipitomastoid sutures. It is classified into two types, type I shows small bones or woven bones, while in type II, woven bones are non-existent. In this study, forty cadavers were conducted and observed the asterion on both sides of skulls showing the approximate ratio of type II and type I was 3:2. The asterion was located by measuring the distances from the asterion to skull landmarks, including inion, the root of zygoma, and mastoid tip. The mean distance between asterion and inion was 62.9 ? 6.0 mm. The mean distance between asterion and the root of zygomatic arch was 58.3 ? 6.1 mm, whereas the mean distance between asterion and mastoid tip was 51.1 ? 5.3 mm. The most common location related to the asterion was the dural venous sinuses on 65 % of tested sides, followed by infratentorial dura and supratentorial dura (25 % and 10 %, respectively). However, the authors found no differences between sexes, sides, and types in any underlying structures.

RESUMEN: El asterion es la unión de las suturas lambdoidea, parietomastoidea y occipitomastoidea. Clasificado en dos tipos, el tipo I muestra huesos pequeños o hueso laminar, mientras que en el tipo II, el hueso laminar es inexistente. En este trabajo se estudiaron 40 cadáveres y se observó el asterion en ambos lados de los cráneos correspondientes, mostrando una proporción aproximada de tipo II y tipo I de 3:2. El asterion se localizó midiendo las distancias asociadas a puntos de referencia del cráneo: el inion, la raíz del arco cigomático y el ápice del proceso mastoides. La distancia media entre el asterion y el inion fue de 62,9 ? 6,0 mm. La distancia media entre el asterion y la raíz del arco cigomático fue de 58,3 ? 6,1 mm, mientras que la distancia media entre el asterion y el ápice del proceso mastoides fue de 51,1 ? 5,3 mm. La localización más común relacionada con el asterion fueron los senos venosos durales en el 65 % de los lados evaluados, seguido de la duramadre infratentorial y la dura supratentorial (25 % y 10 %, respectivamente). Sin embargo, los autores no encontraron diferencias entre sexo, lados y tipo en ninguna estructura subyacente.

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.

Anatomical variations and morphometric study of pterion in a Thai population associated with clinical implications / Variaciones anatómicas y estudio morfométrico del pterion en una población tailandesa asociada con implicaciones clínicas

SUMMARY: The objective of this study was to consider the type of variation and to estimate the landmarks for localizing the pterion. One hundred twenty Thai dry skulls were selected randomly from the Forensic Osteology Research Center, Faculty of Medicine, Chiang Mai University. The distances of the parameters were measured via Vernier caliper. The sphenoparietal type is the most dominant in the Thai population with 88.75 %. In the male, the distance of the midglabella to the pterion was 9.94?0.64 mm The distance of the frontozygomatic suture to the pterion was 35.41?4.38 mm The distance of the zygomatic arch to the pterion was 39.39?4.69 mm and the distance of the mastoid process tip to the pterion was 86.88?4.44 mm In the female, the distance of the midglabella to the pterion was 9.27?0.63 mm The distance of the frontozygomatic suture to the pterion was 33.08?4.12 mm The distance of the zygomatic arch to the pterion was 33.08?4.12 mm and the distance of the mastoid process tip to the pterion was 83.62?5.16 mm. The pterion approach is the most popular method for neurosurgical procedures, and it provides anatomical variations in the pattern. The sphenoparietal type of pterion is the most common form and the stellate type of pterion is the least common form in Thai skulls. Sex influences the location of the pterion. These findings will be of importance to predict the pterion type in Thai skull and estimate the localization of pterion by using a bony landmark. Knowledge of the precise location of the pterion is an important landmark in the neurosurgical approach.

RESUMEN: El objetivo de este estudio fue considerar el tipo de variación del pterion y estimar los puntos de referencia para localizarlo. Se seleccionaron al azar 120 cráneos secos de individuos tailandeses del Centro de Investigación de Osteología Forense de la Facultad de Medicina de la Universidad de Chiang Mai. Las distancias de los parámetros se midieron mediante un caliper Vernier. El tipo esfenoparietal es el más dominante en la población tailandesa con 88,75 %. En el hombre, la distancia de la glabella al pterion fue de 9,94 ? 0,64 mm. La distancia de la sutura frontocigomática fue de 35,41 ? 4,38 mm La distancia del arco cigomático fue de 39,39 ? 4,69 mm y la distancia del ápice del proceso mastoideo al pterion fue de 86,88 ? 4,44 mm. En la mujer, la distancia de la glabella al pterion fue de 9,27 ? 0,63 mm. La distancia de la sutura frontocigomática al pterion fue de 33,08 ? 4,12 mm. La distancia del arco cigomático al pterion fue de 33,08 ? 4,12 mm y la distancia del ápice proceso mastoideo al pterion fue de 83,62 ? 5,16 mm. El abordaje del pterion es el método más utilizado para procedimientos neuroquirúrgicos y proporciona variaciones anatómicas en el patrón. El tipo esfenoparietal del pterion es la forma más común y el tipo estrellado del pterion es la forma menos común en los cráneos tailandeses. El sexo influye en la ubicación del pterion. Estos hallazgos serán importantes para predecir el tipo de pterion del cráneo en tailandeses y a la vez estimar su localización mediante el uso de un punto de referencia óseo. El conocimiento de la ubicación precisa del pterion es un hito impor- tante en el abordaje neuroquirúrgico.

Propuesta de clasificación de huesos suturales / Classification proposal of sutural bones

RESUMEN: Los huesos suturales tienen importancia anatómica y médico-legal. Se observan en las suturas de la cabeza ósea y tradicionalmente son descritos como planos, supernumerarios, irregulares, inconstantes, independientes y de variable morfología y frecuencia. Actualmente, no existe una clasificación única de estos huesos que incorpore todas las categorías descritas en la literatura. El objetivo de este trabajo fue proponer una clasificación actualizada de estos elementos, en función de una revisión bibliográfica exhaustiva y el análisis de cráneos de individuos chilenos. La muestra utilizada correspondió a 113 huesos suturales presentes en 12 cráneos secos, de individuos adultos chilenos. En la clasificación se consideró su ubicación en la cabeza (cráneo o cara), su origen embrionario, su relación con una fontanela, su forma, su posición en la cara y su relación con las tablas óseas. Los datos obtenidos se registraron en formulario especialmente diseñado y se tomaron fotografías digitales. Como resultado general, pudimos desarrollar una propuesta de clasificación de huesos suturales completa y satisfactoria y con ella se analizó los huesos de la muestra, pudiendo evidenciar la presencia de todas las categorías del instrumento. También pudimos constatar que en la totalidad de los cráneos utilizados se observaron huesos suturales, que los cráneos masculinos presentan un mayor número de estos huesos, pero que en los cráneos femeninos fue posible reconocer todas los tipos de huesos suturales, entre otros resultados. También se evidenció un tipo de hueso sutural no descrito anteriormente, el hueso sutural craneal puntiforme. Como conclusión de este trabajo, es importante destacar que los huesos suturales presentan características comunes a otras estructuras utilizadas en identificación forense, es decir, son perennes, únicos, de fácil observación, de fácil comparación y gran variabilidad, por estas razones la presente propuesta de clasificación permite ser planteada como una metodología auxiliar en la identificación humana.

SUMMARY: The sutural bones have anatomical and medico-legal importance. They are observed in the sutures of the bony head and are traditionally described as flat, supernumerary, irregular, inconstant, independent and of variable morphology and frequency. Currently, there is no single classification of these bones that incorporates all the categories described in the literature. The objective of this work was to propose an updated classification of these elements, based on an exhaustive bibliographic review and the analysis of the skulls of Chilean individuals. The sample used corresponds to 113 sutural bones present in 12 dry skulls of Chilean adults. The classification considers its location on the head (skull or face), its embryonic origin, its relationship to a fontanelle, its shape, its position on the face, and its relationship to bone tables. The data obtained was recorded in a specially designed format and digital photographs were taken. As a general result, we were able to develop a complete and satisfactory classification of sutural bones proposal and with it, the bones of the sample were analyzed, showing the presence of all categories of the instrument. We were also able to verify that sutural bones were observed in all the skulls used, that male skulls present a greater number of these bones, but that in the female skulls it was possible to recognize all types of sutural bones, among other results. A type of sutural bone not previously described, the shaped point cranial sutural bone, was also evidenced. As a conclusion to this work, it is important to highlight that sutural bones present characteristics common to other structures used in forensic identification, that is, they are perennial, unique, easily observed, easily compared and great variability, for these reasons the present classification proposal allows it to be proposed as an auxiliary methodology in human identification.

Complete sagittal suture closure evaluation based on post mortem computed tomography.

Age assessment at the time of death is of great importance when an unidentified skeleton or corpse is found. Obliteration of cranial sutures has been used for age assessment regarding anthropology as non - metrical method of direct bone inspection. The aim of our study was to assess sagittal suture closure in the contemporary population of Polish men using postmortem computed tomography. A total of 255 male skulls were analyzed with the use of multiplanar reconstruction (MPR) and volume rendering technique (VRT) images, which were based on whole-body postmortem computed tomography scans. The individuals of Polish origin were of precisely known metrical age. The sagittal sutures were analyzed across their entire thickness (including both the outer and inner aspect of bone) and along their entire length via frontal sections, using the sagittal suture division into 4 segments. This study showed that the earliest signs of suture closure occur in S4 on the inner side of the calvaria at a mean age of 50.48 years, but the youngest person with starting obliteration process was 13.37 years. This is prove that exist variability which must be count during biological age estimation. Additionally, VRT visualisation shows that the fourth state of obliteration does not mean that obliteration was ended. Further analyses of cranial suture closure are needed to obtain reliable methods for postmortem estimation of the age at the time of death in contemporary populations. The use of postmortem computed tomography may offer additional opportunities for contemporary analysis of skeletal material.

Mathematical modeling of palatal suture pattern formation: morphological differences between sagittal and palatal sutures.

The median palatal suture serves as a growth center for the maxilla; inadequate growth at this site causes malocclusion and dental crowding. However, the pattern formation mechanism of palatal sutures is poorly understood compared with that of calvarial sutures such as the sagittal suture. In the present study, therefore, we compared the morphological characteristics of sagittal and palatal sutures in human bone specimens. We found that palatal suture width was narrower than sagittal suture width, and the interdigitation amplitude of the palatal suture was lower than that of the sagittal suture. These tendencies were also observed in the neonatal stage. However, such differences were not observed in other animals such as chimpanzees and mice. We also used a mathematical model to reproduce the differences between palatal and sagittal sutures. After an extensive parameter search, we found two conditions that could generate the difference in interdigitation amplitude and suture width: bone differentiation threshold [Formula: see text] and growth speed c. We discuss possible biological interpretations of the observed pattern difference and its cause.