Sex estimation based on foramen magnum: a three-dimensional geometric morphometrics approach / Estimación del sexo basado en el foramen magno: un enfoque de morfometría geométrica tridimensional

SUMMARY: The foramen magnum is an important topographic opening which connects cranial cavity and spinal canal. The analysis of the bone material established that there are differences in the shape of the foramen magnum between individuals. The aim of this study was to determine sex based on shape and size of foramen magnum using geometric morphometrics method. A study was performed on three-dimensional models (3D models) of 214 human skulls of known sex and known age (141 male skulls and 73 female skulls). The skulls are located at the museum of Medical Faculty, University of Sarajevo. Skulls belong to Bosnian population from the mid-twentieth century. All examined skulls were scanned with a laser scanner to obtain their 3D models. On 3D models of the examined skulls, four landmarks were marked on foramen magnum. Analysis of sex determination was performed using the MorphoJ program. Results of this study showed that there are sex differences in the shape and size of the foramen magnum. Sex determination based on the shape and size of the foramen magnum was showed 65.25 % accuracy for male and 63.01 % accuracy for female using geometric morphometrics method. Examination of the effect of size of foramen magnum on sexual dimorphism of shape of foramen magnum showed a statistically significant effect. Sex determination based just on the shape of foramen magnum using geometric morphometrics method was possible with 62.41 % accuracy for male and 58.90 % accuracy for female on examined sample. Sex differences on shape and size of foramen magnum were found using geometric morphometrics method on three-dimensional models of the examined skulls. The percentage of accuracy was higher for male based on the shape and size of the foramen magnum than for female.

El foramen magno es una importante abertura topográfica que conecta la cavidad craneal y el canal espinal. El análisis del material óseo estableció que existen diferencias en la forma del foramen magno entre individuos. El objetivo de este estudio fue determinar el sexo en función de la forma y el tamaño del foramen magno utilizando morfometría geométrica. El estudio se realizó en modelos tridimensionales (modelos 3D) de 214 cráneos humanos de sexo y edad conocidos (141 cráneos masculinos y 73 cráneos femeninos). Los cráneos se encuentran en el museo de la Facultad de Medicina de la Universidad de Sarajevo. Los cráneos pertenecen a población bosnia de mediados del siglo XX. Todos los cráneos examinados fueron escaneados con un escáner láser para obtener sus modelos 3D. En los modelos 3D de los cráneos examinados, se marcaron cuatro puntos de referencia en el foramen magno. El análisis de determinación de sexo se realizó utilizando el programa MorphoJ. Los resultados de este estudio mostraron que existen diferencias de sexo en la forma y el tamaño del foramen magno. La determinación del sexo basada en la forma y el tamaño del foramen magno mostró una precisión del 65,25 % para los hombres y del 63,01 % para las mujeres utilizando morfometría geométrica. El examen del efecto del tamaño del foramen magno sobre el dimorfismo sexual de la forma del foramen magno mostró un efecto estadísticamente significativo. La determinación del sexo basada solo en la forma del foramen magno utilizando morfometría geométrica fue posible con una precisión del 62,41 % para los hombres y del 58,90 % para las mujeres en la muestra examinada. Se encontraron diferencias de sexo en la forma y el tamaño del foramen magno utilizando morfometría geométrica en modelos tridimensionales de los cráneos examinados. El porcentaje de precisión fue mayor para los hombres en función de la forma y el tamaño del foramen magno que para las mujeres.

Magnificent harmony in morphometric measurements of orbita and foramen magnum / Armonía magnífica en medidas morfométricas de órbita y foramen magno

SUMMARY: The foramen magnum (FM) is the key component of the craniovertebral junction, which connects the brain stem and medulla spinalis and is closely related to vital structures. FM dimensions are of great clinical importance. Considering the similarity in shape between FM and orbita, we thought that there might be a relationship between the lengths (sagittal diameter) and widths (transverse diameter) of these structures. Since it is not possible to reach FM directly, we set up our hypothesis as can we calculate the foramen magnum dimensions from orbital measurements before proceeding to costly tests. We also investigated this harmony in the skulls we used in the study. In the study, 21 dried skull bones from the Turkish population were used. FM and right Orbital length and width measurements were made. Precision digital caliper was used for measurements. Statistical validity and reliability analyzes were performed to prove the agreement between the measurements. We found that the length of the orbit and FM in the sagittal plane is close to each other, with 34.74±2.11 mm and 34.99±3.0 mm, and the width of the orbit in the coronal plane is approximately 1.40 times the width of the FM. We proved that the estimation of FM dimensions based on orbital measurements is also statistically valid and safe. Using orbital measurements, it is possible to estimate FM dimensions which are difficult to reach directly in living humans.

El foramen magno (FM) es el componente clave de la unión craneovertebral, que conecta el tronco encefálico y el bulbo raquídeo y está estrechamente relacionado con las estructuras vitales. Las dimensiones FM son de gran importancia clínica. Teniendo en cuenta la similitud de forma entre FM y órbitas, consideramos que podría haber una relación entre las longitudes (diámetro sagital) y las anchuras (diámetro transversal) de estas estructuras. Dado que no es posible llegar al FM directamente, establecimos nuestra hipótesis y calculamos las dimensiones del foramen magno a partir de mediciones orbitales antes de proceder a costosas pruebas. También investigamos esta armonía en los cráneos que usamos en el estudio. En el estudio, se utilizaron 21 huesos de cráneo secos de la población turca. Se realizaron mediciones FM y de longitud y anchura orbitales. Para las mediciones se utilizó un calibrador digital de precisión. Se realizaron análisis estadísticos de validez y confiabilidad para probar la concordancia entre las mediciones. Encontramos que la longitud de la órbita y FM en el plano sagital es cercana entre sí, con 34,74±2,11 mm y 34,99±3,0 mm, y el ancho de la órbita en el plano coronal es aproximadamente 1,40 veces el ancho de la FM. Demostramos que la estimación de las dimensiones FM basadas en mediciones orbitales también es estadísticamente válida y segura. Empleando mediciones orbitales, es posible estimar dimensiones FM que son difíciles de alcanzar directamente en humanos vivos.

Dimorfismo sexual del agujero magno en tomografías de una población peruana / Sexual dimorphism of the foramen magnum in CT scans of a Peruvian population

Introducción: La base del cráneo es una estructura compacta, muy resistente a los daños físicos, la robustez del hueso occipital y la posición anatómica protegida del agujero magno bajo una profundidad de tejido blando pueden hacerlo menos vulnerable a la fragmentación y a los efectos de los procesos tafonómicos en comparación con otras estructuras óseas, lo que permite utilizarlo para estimar el dimorfismo sexual. Objetivo: Establecer la relación entre el dimorfismo sexual y la morfometría del agujero magno en tomografías de pacientes mayores o iguales a los 18 años que asistieron a consultorios privados en Lima metropolitana, durante los años 2015 al 2020. Materiales y métodos: El estudio se desarrolló con 239 tomografías (88 masculinos y 151 femeninos). Se realizaron mediciones del agujero magno de los diámetros anteroposterior máximo (DAPM), transversal máximo (DTM) y el área se estableció mediante la fórmula de Teixeira (1982). Resultados: El DAPM presentó una media en el sexo masculino de 37,182 +/- 2,4012 mm y en el femenino de 34,795 +/- 2,1086 mm, mientras que para el DTM se estableció una media en el sexo masculino de 32,517 +/- 2,3463 mm y para el femenino de 30,514 +/- 2,2084 mm, en el área según Teixeira (1982) en el sexo masculino se observó una media de 957,21390 +/- 115,162403mm2 y en el femenino de 840,11055 +/- 93,775088mm2. Se establece una relación estadística (p<0.05) entre los parámetros DAPM, DTM, A Teixeira (1982) entre ambos sexos. Conclusión: Existe relación entre el dimorfismo sexual y la morfometría del agujero magno, con una predicción de 71.96%

Introduction: The base of the skull is a compact structure, very resistant to physical damage, the robustness of the occipital bone and the protected anatomical position of the foramen magnum under a depth of soft tissue may make it less vulnerable to fragmentation and to the effects of taphonomic processes compared to other bone structures, allowing it to be used to estimate sexual dimorphism. Objective: To establish the relationship between sexual dimorphism and the morphometry of the foramen magnum in CT scans of patients older or equal to 18 years of age who attended private clinics in metropolitan Lima, during the years 2015 to 2020. Materials and methods: The study was developed with 239 tomographies (88 male and 151 female). Foramen magnum measurements of the maximum anteroposterior diameters (DAPM), maximum transverse (DTM) were performed and the area was established using Teixeira's (1982) formula. Results: The DAPM presented a mean in the male sex of 37.182 +/- 2.4012 mm and in the female sex of 34.795 +/- 2.1086 mm, while for the DTM a mean was established in the male sex of 32.517 +/- 2, 3463 mm and for the female of 30.514 +/- 2.2084 mm, in the area according to Teixeira (A Teixeira) in the male sex a mean of 957.21390 +/- 115.162403mm2 and in the female sex of 840.11055 +/- 93.775088mm2 was observed. A statistical relationship (p<0.05) was established between the parameters DAPM, DTM, A TEIXEIRA between both sexes. Conclusion: There is a relationship between sexual dimorphism and foramen magnum morphometry, with a prediction of 71.96%

Anatomical Observation of Different Shapes of Foramen Magnum and Its Clinical Implications: A Study in Dry Adult Human Skulls of Indian Population

Background: Understanding of thoroughly explained anatomical basis is must for various surgical approaches at the craniovertebral junction. High mortality and morbidity are anticipated during the surgical procedures when undertaken without in depth anatomical knowledge. With so much clinical importance in this area, our study will present a thorough understanding in terms of skull. Objectives: The aim of the present study is to evaluate the various shapes of foramen magnum in dry adult human skulls of Indian population and to find out their clinical correlation. Materials and methods: 347 dried adult human skull base obtained from the Department of Anatomy, Geetanjali Medical College and Hospital, Udaipur, Rajasthan and other medical colleges were used in the present study. All the dry adult human skulls were observed from outer side at their base by naked eyes to determine the shape of foramen magnum. It was classified into one of the following shapes: - Oval, round, tetragonal, egg shaped, hexagonal, pentagonal and irregular. Results: The shape of the foramen magnum in dry skulls were oval in 44.95%, round in 30.84%, hexagonal in 9.23%, irregular in 6.63%, pentagonal in 5.19%, tetragonal in 1.73 %, and egg shaped in 1.44%. Conclusion: Inferences of the present study in the form of variations in the shapes of foramen magnum will be useful to the neurosurgeons, radiologists, orthopedics, anthropologists, forensic experts as well as anatomists. Further these data can be used as an anatomical reference for the researchers.

Golden ratio for the foramen magnum on CT images: a morphological and morphometrical study / Proporción áurea para el foramen magnum en imágenes de TC: un estudio morfológico y morfométrico

SUMMARY: The foramen magnum (FM) is a transition zone between the spine and skull. There is a study in the literature showing the golden ratio (4.62) and harmony between both FM and the anteroposterior and transverse diameters of the skull. The aim of this study is to examine the existence of this ratio on CT images and to investigate whether this ratio changes according to the FM shape types. In this study, 402 adult CT images belonging to the Turkish population were examined. Maximum cranial length (MCL), maximum cranial width (MCW) and the FM length (FML) and FM width (FMW) were measured. The different shapes of the FM were macroscopically classified. The number and incidence of each type in the studied skull was registered. In the 402 CT images used in the study, 12 FM shapes were detected. Three of the shape types observed in our study have not been reported in the literature until now, and were found in our study for the first time. In addition, our data supported that by using the ratio of 4.62, there was a great harmony between the skull and FM. The results obtained from the research show that there is a ratio of 4.62 between the basic cranial measurements and FM dimensions in all shapes except triangular shape. It is thought that repeating the calculated coefficients over more different FM shapes will contribute to the effectiveness of the proposed golden ratio.

RESUMEN: El foramen magno (FM) es una zona de transición entre la columna y el cráneo. Existe un estudio en la literatura que muestra la proporción áurea (4,62) y la armonía entre el FM y los diámetros anteroposterior y transversal del cráneo. El objetivo de este estudio fue examinar la existencia de esta relación en las imágenes de TC e investigar si esta relación cambia según los tipos de forma del FM. Se examinaron 402 imágenes de TC de adultos pertenecientes a la población turca. Se midieron la longitud craneal máxima, el ancho craneal máximo y la longitud del FM y la anchura del FM. Las diferentes formas del FM se clasificaron macroscópicamente. Se registró el número e incidencia de cada tipo en el cráneo estudiado. En las 402 imágenes de TC utilizadas en el estudio, se detectaron 12 formas de FM. Tres de los tipos de formas observados en nuestro estudio no se han reportado en la literatura consultada describiéndose por primera vez. Además, nuestros datos respaldaron que al usar la proporción de 4,62, había una armonía importante entre el cráneo y el FM. Los resultados obtenidos de la investigación muestran que existe una relación de 4,62 entre las medidas craneales básicas y las dimensiones de la FM en todas las formas excepto en la triangular. Se cree que la repetición de los coeficientes calculados en más formas de FM diferentes contribuirá a la eficacia de la proporción áurea propuesta.

Meningiomas de fosa posterior: nomenclatura con orientación anatomo-quirúrgica y presentación de casos ilustrativos / Posterior fossa meningiomas: nomenclature with anatomical-surgical orientation and presentation of illustrative cases

Introducción: Los meningiomas de la fosa posterior representan el 20% de todos los meningiomas intracraneales. Cada subtipo tiene una base de implantación, abordaje quirúrgico y morbimortalidad postoperatoria muchas veces diferente. Advertimos que en reuniones científicas y publicaciones no se sigue una forma de clasificar uniforme, sencilla y clara con orientación netamente quirúrgica. Esto genera que el neurocirujano en formación no cuente con herramientas suficientes para la toma de decisiones. Objetivos: Proponer una clasificación sencilla de los meningiomas de la fosa posterior con un fundamento anatomo-quirúrgico y presentar casos ilustrativos de cada subtipo. Materiales y métodos: Se estableció una nomenclatura considerando reportes previos, el criterio anatómico y la experiencia quirúrgica de los autores. Se presentaron casos revisando las historias clínicas y los archivos de imágenes correspondientes a cada subtipo de la clasificación. Resultados: Representamos a la fosa posterior como un compartimento con 3 anillos: el superior se divide en medial, lateral-anterior y lateral-posterior; el medio se divide en 6 variantes: clivales puros, esfeno-petro-clivales, petrosos anteriores, petrosos posteriores y de la convexidad suboccipital medial y lateral; el inferior se divide en anterior, lateral derecho, lateral izquierdo y posterior. Conclusión: Los meningiomas del anillo superior pueden resolverse mediante una vía suboccipital medial o lateral; los del anillo medio tienen un espectro de opciones más diverso; los del anillo inferior -siguiendo el esquema de división en cuadrantes de un reloj- pueden resolverse por medio de un abordaje suboccipital medial o extremolatera

Introduction: Posterior fossa meningiomas represent 20% of all meningiomas, being each location associated with a specific approach, morbidity and mortality. The actual classifications are focus on the dural attachment, without associating the anatomical with the surgical aspects, useful to the young neurosurgeons for decision making. Objectives: To propose a classification of the posterior fossa meningiomas with an anatomical-surgical view including the presentation of cases. Materials and Methods: A nomenclature was established concerning previous reports, the anatomical criteria and the surgical experience of the authors. Cases were presented by reviewing the medical records corresponding to each subtype of the proposed classification. Results: We represent the posterior fossa as a 3 rings compartment: the upper one is divided into medial, anterior-lateral and posterior-lateral; the middle ring is divided into 6 variants: pure clival, spheno-petro-clival, anterior petrosal, posterior petrosal, and medial and lateral suboccipital convexity; the lower ring is divided into anterior, right lateral, left lateral, and posterior. Conclusion: Superior ring meningiomas can be resolved by a medial or lateral suboccipital approach; middle ring meningiomas have a more diverse spectrum of options; while meningiomas of the inferior ring - following the scheme of division into quadrants of a clock - can be resolved by means of a medial or extreme-lateral suboccipital approach.

Tailored Surgical Approaches for Foramem Magnum Tumors

Objective To describe our surgical techniques, analyze their safety and their postoperative outcomes for foramen magnum tumors (FMTs). Methods From 1986 to 2014, 34 patients with FMTs underwent surgeries using either the lateral suboccipital approach, standard midline suboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions. Results In the present series, there were 22 (64.7%) female and 12 (35.2%)male patients. The age of the patients ranged from12 to 63 years old.We observed 1 operativemortality (2.9%). A total of 28 patients (82.3%) achieved a score of 4 or 5 in the Glasgow Outcome Scale (GOS). Gross total resection (GTR) was obtained in 22 (64.7%) patients. After the surgery, 9 (26%) patients developed lower cranial nerve dysfunction (LCNd) weakness. The follow-up varied from 1 to 24 years (mean: 13.2 years). Conclusion Themajority of tumors located in the FMcan be safely and efficiently removed usingeither thelateral suboccipital approach, standardmiddlelinesuboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions.

Morbimortalidad Asociada A La Cirugia De Meningioma Del Foramen Magno. Revision De La Literatura: Reporte De Caso / Morbimortality Associated With The Foramen Magno Meningioma Surgery: A Case Report

Resumen Los meningiomas son tumores del sistema nervioso central que representan alrededor del 14,3% a 19%, de ellos solo un 1.8% a 3,2% surge en el foramen magno, por años el abordaje de esta clase de tumores conllevaba una gran morbimortalidad asociada debido a que el foramen magno contiene una serie de estructuras anatómicas y neurovasculares críticas, sin embargo con el progreso de las técnicas quirúrgicas, el manejo de la anestesia neurológica y la formación de neurocirujanos con experiencia en cirugías de base de cráneo, ha podido revertir estos resultados y hacer de la cirugía una alternativa segura con bajas tasas de complicaciones. El presente trabajo pretende revisar la literatura acerca de la morbimortalidad asociada a los meningiomas de foramen magno y presentar un caso abordado en nuestro centro.

The meningiomas are tumors of the central nervous system that represent around 14.3% to 19%, of them only 1.8% to 3.2% arise in the foramen magnum, for years the approach of this class of tumors entailed a great associated morbidity and mortality because the foramen magnum contains a series of critical anatomical and neurovascular structures, however with the progress of surgical techniques, the management of neurological anesthesia and the training of neurosurgeons with experience in skull base surgeries, it has been able to reverse these results and make surgery a safe alternative with low complication rates. The present work aims to review the literature about morbidity and mortality associated with meningiomas of foramen magnum and present a case addressed in our center.

Aplicabilidade do índice forame magno em crânios humanos de indivíduos do nordeste brasileiro / Applicability of the foramen magnum index on human skulls of individuals from northeastern Brazil

Introdução: O Índice Forame Magno (IFM) é um método secundário para o estabelecimento do sexo no processo de identificação humana. Objetivo: Averiguar a aplicabilidade do IFM para a determinação do sexo em uma amostra brasileira. Material e Método: Estudo cego e transversal, com amostra composta por 209 crânios pertencentes ao Centro de Estudos em Antropologia Forense da Faculdade de Odontologia de Pernambuco/Universidade de Pernambuco (CEAF/FOP/UPE). Com o uso de paquímetro digital de precisão, foram realizadas medidas correspondentes à largura e ao comprimento do forame magno, aplicando-as à fórmula IFM = largura/comprimento x 100. O sexo foi classificado de acordo com tabela de referência para o índice supracitado. Para a análise estatística utilizaram-se os testes T-Student e Qui-Quadrado de Pearson, com nível de significância de 5,0%. Resultados: Todas as variáveis quantitativas apresentaram diferenças estatisticamente significantes para os sexos (p<0,05), porém não houve discrepâncias entre os mesmos quanto à utilização do IFM (p=0,965). O acerto do IFM para o sexo masculino (99,1%), mas para o sexo feminino este método não classificou nenhum crânio corretamente. Conclusão: As dimensões do Forame Magno apresentaram dimorfismo sexual, porém o IFM não deve ser utilizado como metodologia para a determinação do sexo da amostra brasileira estudada.

Introduction: The Foramen Magnum Index (IMF) is a secondary method for the establishment of the sex in the process of human identification. Objective: To investigate the applicability of FMI to the determination of sex in a Brazilian sample. Material and Method: Blind and transversal study, with sample composed of 209 skulls belonging to the Forensic Anthropology Center of the Dentistry School of Pernambuco/Universidade de Pernambuco (CEAF/FOP/UPE). With the aid of a digital caliper, measurements were made on the width and length of the Foramen Magnum, applying them to the FMI formula FMI = width/length x 100. The sex was classified according with the reference table to the above mentioned index. For the statistical procedures, were used the testes Student T and Pearson's Chi-Square, with a significance level of 5%. Results: All the quantitative variables presented statistically significant differences for the sexes (p<0,05), but there were no discrepancies between them regarding the use of the FMI (p=0.965). The concordances of the FMI for males (99.1%) were higher than those of females, which did not have any cranial classification correctly. Conclusion: The FMI should not be used as a single methodology for determining the sex of the Brazilian sample studied

Comparison of Morphometry of Foramen Magnum and Posterior Cranial Fossa in Dry Human Skull

Bougie is an important adjunct in the anaesthesiologist armoury for a difficult airway1. Physical damage to bougie leading to airway trauma is rare but can be catastrophic. We report a case of an anticipated difficult extubation, where the bougie, used to extubate over the tube broke and migrated into the trachea indicating the need of a protocol for routine inspection of bougie which should be strictly adhered to

Sexual dimorphism of foramen magnum: a NCCT based study

Background:Radiological determination of gender relies predominantly on the skeletal radiology and assumes importance in mass natural disasters, bomb explosions, exhumations and warfare where skeletal fragmentation is common. Varied literature is present regarding the role of foramen magnum in establishing gender identification.The objective of the study wasto establish normative values of cross-sectional area of foramen magnum in both genders using NCCT and try to ascertain any significant difference in cross-sectional area in the two genders which may help in gender identification.Methods:NCCT head images of 378 subjects were analysed in individuals beyond the age of skeletal immaturity. Free ROI technique using electronic calliper tool was used. The cross-sectional area of foramen magnum was automatically obtained after tracing its whole inner circumference.Results:Mean cross-sectional area of foramen magnum in females was 806.79±106.58 mm2and was 878.33±98.42 mm2in males. Although the cross-sectional area in males was greater than females no statistically significant difference was found. The correlation coefficient was found to be weaker (R=0.0413). Conclusions: No statistically significant difference was found between the two genders. The correlation coefficient was also weak to draw any inference about the gender of the skull on CT imaging. Further studies are needed to include other parameters like the sagittal and transverse diameters of foramen magnum in a larger sample to show importance of foramen magnum, if any, in helping gender identification of skeletal remains

Foramen Magnum: Morphometry, Possible Variation In The Shape And Its Clinical Implication

Introduction: Foramen magnum is midline opening in the occipital bone in the floor of posterior cranial fossa. Morphometryof cranium also helps in establishing the origin of various neurological and skeletal pathologies and also designing varioussurgical procedures and approaches.Methods: We conducted a study on 50 dry skull bones in the Department of Anatomy, Government Medical College and Hospital,Chandigarh. The foramen magnum was analyzed for its shape, anteroposterior (AP) diameter, width/transverse diameter (TD),area, perimeter, and FM index. All the measurements were taken with Vernier caliper and were statistically evaluated.Results: The common shape observed was hexagonal in 45% of cases. The mean of AP and TD was found to be 34.44 mmand 30.46 mm. AP diameter was more than TD. FM index and perimeter were found to be 98.91 mm and 88.44. However, areaof foramen magnum was observed to be 745.727 mm2.

Value of MRI and CTA in preoperative assessment of tumors in foramen magnum region / 中国医学影像技术

Objective: To explore the clinical value of MRI and CTA in the preoperative assessment of tumors in the foramen magnum region. Methods: Clinical and imaging data of 32 patients with foramen magnum region tumors confirmed by surgical pathology were retrospectively analyzed. Tumor location, extent and the relationship of the tumor and surrounding important structures were assessed and compared with surgical findings. Results: Among 32 patients with foramen magnum region tumors, there were 29 cases of benign tumors, including 4 cases of angioblastomas, 3 cases of ependymoma, 2 cases of hairy cell astrocytoma, 13 cases of meningioma, 5 cases of schwannoma, 1 case of lipoma and 1 case of epidermoid cyst; there were 3 cases of malignant tumor, including 1 case of chondromatoid chordoma, 1 case of melanoma and 1 case of metastasis. Nine tumors located in intramedullary, 23 in extramedullary, including ventral in 5 cases, ventrolateral in 7 cases, dorsal in 11 cases. The diagnostic accuracy of MRI was 93.75% (30/32), and the evaluation of tumor scope was consistent with that of surgery. The coincidence rate of CTA in evaluation on supplying artery with intraoperative findings was 100%. Conclusion: MRI and CTA play an important role in evaluating the location and extension of tumors in the foramen magnum region, as well as the relationship with adjacent tissue and vessels, which is useful for determining the surgical approach, the extent of tumor resection and management of the surrounding vessels in clinical routine.

The Clock Is Ticking – Brain Atrophy in Case of Acute Trauma? / 대한신경손상학회지

OBJECTIVE: Brain atrophy and brain herniation are gaining a lot of attention separately, but a limited amount of studies connected them together, and because of this, we are going to review and examine the subject in the current meta-analysis. METHODS: The authors collected data reporting brain atrophy of alcoholic and schizophrenic cause, as well as data on control patients, all of which was published on MEDLINE between 1996 and 2018. The included 11 articles were processed with a statistical program. RESULTS: We found that the pericerebral space is unequal among the groups, while the intracranial volume is strongly correlated to the biggest foramen of the body. The effect of this inequality, however, is expressed in emergency cases, where the patients with brain atrophy will have more time before the final stage of brain herniation CONCLUSION: The current study raises a controversial issue that requires careful investigation and high attention from the health care personnel.

Sexing the cranium from the foramen magnum using discriminant analysis in a brazilian sample

Abstract In the identification process, the foramen magnum has shown controversial results in sex estimation. The present study aimed to analyze the morphometric variables of the foramen magnum in Brazilian adult cranium for sex estimation. The sample was composed of 100 craniums (53 males and 47 females) from the documented collection of the Institute of Teaching and Research in Forensic Sciences. The protocol measurement was constituted of two linear measurements: maximum length of the foramen magnum and maximum breadth of the foramen magnum and two formulas to calculate the area, method one (M1) and method two (M2). Descriptive statistics showed statistically significant differences between sex (p<0.05) for all variables. The univariate discriminant functions showed an accuracy between 56.0-62.0%, and the multivariate analysis showed a percentage of accuracy between 60.0-65.0%, the greatest accuracy was found combining the two linear measurements with M1(71.7%), even after cross-validation (66%). Receiver Operating Characteristic (ROC) curve analysis showed that M2 is the best parameter for estimating sex (AUC=0.693). A reference table for Brazilians using the foramen magnum parameters was developed based on the results of the ROC curve analysis. In conclusion, the foramen magnum should be used with caution to estimate sex in forensic cases of fragmentary craniums, due to the limited accuracy.

Resumo No processo de identificação humana, a análise do forame magno apresenta resultados controversos para estimativa do sexo. O presente estudo teve como objetivo analisar as variáveis morfométricas do forame magno em crânios adultos brasileiros para estimação sexual. A amostra foi composta por 100 crânios (53 sexos masculino e 47 sexo feminino) pertencentes a coleção osteológica documentada do Instituto de Ensino e Pesquisa em Ciências Forenses. A medida do protocolo foi constituída por duas medidas lineares: comprimento máximo do forame magno e largura máxima do forame magno e duas fórmulas para calcular a área, método um (M1) e método dois (M2). As estatísticas descritivas evidenciaram diferenças estatisticamente significativas (p<0,05) para todas as variáveis. As funções discriminantes univariadas apresentaram uma porcentagem de acerto entre 56,0-62,0% e a análise multivariada mostrou uma porcentagem de acerto entre 60,0-65,0%. A análise da curva ROC apontou que M2 é o melhor parâmetro para estimar o sexo (AUC=0,693). Uma tabela de referência para brasileiros que utilizam os parâmetros do forame magnum foi desenvolvida com base nos resultados da análise da curva ROC. Em conclusão, o foram e magnum deve ser usado com precaução para estimar o sexo em casos forenses de cranio fragmentado, devido à precisão limitada.

Endoscopic Endonasal Approach to Foramen Magnum Meningioma­Technical Note and Case Example

Foramen magnum (FM) tumors represent one of the most complex cases for the neurosurgeon, due to their location in a very anatomically complex region surrounded by the brainstem and the lower cranial nerves, by bony elements of the craniocervical junction, and by the vertebrobasilar vessels. Currently, the open approach of choice is a lateral extension of the posteriormidline approach including far lateral, and extremelateral routes. However, the transoraltranspharyngeal approach remains the treatment of choice in cases of diseases affecting the craniocervical junction. For very selective cases, the endoscopic endonasal route to this region is another option.We present a case of a ventral FM meningioma treated exclusively with the endoscopic endonasal approach.

Foramen Magnum Meningioma Presenting with Cough Syncope (Case Report and Review of the Literature)

Foramen magnum meningiomas cause different symptoms based on the size and the location of the tumor. They often present with involvement of the long tracts and of the lower cranial nerves.Ataxia and occipitocervical headache are other common symptoms. In the present study, we report a case of foramen magnum meningioma presenting with cough syncope. A mass lesion located anterolateral to the foramenmagnumwas detected in a 38-year-oldmanduring amagnetic resonance imaging (MRI) exam; the lesion extended from the inferior clivus to the level of the C2 vertebra. The neural axis has pushed towards posterior and contralateral side by the mass. We think that syncope occurred due to the encasement of the vertebral arteries by the tumor in addition to the compression of the neural axis. The posterolateral approach without condylar resection provides a safe surgical plane for total excision of these tumors. In our case, the tumor was totally removed and the syncope episodes were resolved.

Morphometric Analysis Of Foramen Magnum In Adult Human Dry Skull Of Gujarat Region

Background: Morphometric analysis of the foramen magnum of dry human skulls in Gujarat region was carriedout to demonstrate the anatomical variations in morphology. The measurements of the foramen magnum areclinically important because vital structures passing through it. There are certain diseases associated withcompression of structure present in foramen magnum like arnold chiari malformation (tonsillar herniation),achondroplasia, stenosis of foramen magnum, meningioma and atlanto-occipital fusion.Objectives: The aim of this study was to measure anteroposterior & transverse diameter of foramen magnum,surface area and index of foramen magnum and to observe its various shapes.Materials and methods: 326 dry skulls of adult human being were studied. Antero-posterior and TransverseDiameter were measured by using a digital vernier caliper. The surface area and foramen magnum index werecalculated. The cranial base was visually assessed for the shape of foramen magnum.Results: The mean antero-posterior and transverse diameter of the foramen magnum were 34.18 ± 2.74 mm and28.49 ± 2.13 mm respectively. The mean surface area and the foramen magnum index were 766.86 ± 104.76 mm2and 83.60 ± 6.21 mm respectively. The percentages of different shapes of foramen magnum were: Oval (42.33%),Round (32.82%), Tetragonal (8.59%), Hexagonal (7.67%), Pentagonal (4.60%), and irregular (3.99%).Conclusion: The knowledge of various dimensions & shape of the foramen magnum help to determine somemalformations like arnold chiari syndrome in which the transverse diameter is increased. The antero-posteriordiameter of foramen magnum was more than the transverse diameter and most common shape of foramenmagnum was found to be Oval.

A Cadaveric Study Of The Internal Occipital Crest And Vermian Fossa With Its Clinical Significance

Background: The anatomical variabilities of the internal occipital crest (IOC) and vermian fossa (VF) may influencethe related dural venous sinuses and further effect the flow of the cerebrospinal fluid. It is also associated withthe pathologies around the foramen magnum like Arnold Chiari malformation, certain cases of cerebellar corticaldysplasia.Aim: The present study was designed to explore and evaluate the morphological and morphometric details of theIOC and VF.Materials and Methods: The study was conducted on 40 adult cadavers (23 males & 17 females). The morphologyand morphometry of IOC and VF were studied. Based on the observations, the VF was classified into five types:Type 1- classical (well defined fossa), Type II-short triangular, Type III- elongated triangular, Type IV-quadrangularand Type V-deviated.Results: The IOC was found to be variable both in terms of morphology and morphometry. The morphologicalobservations included varied shapes, i.e., sharp (65%), blunt (30 %) and ill-defined (5 %). The length of the IOCwas also variable with a mean length of 2.97 ± 0.16 cm. The mean width at upper, middle and lower levels were0.9 ± 0.10 cm, 0.75 ± 0.17 cm, 1.10 ± 0.12 cm respectively.The incidence of the VF was found to be about 80%. The VF was classified into types based on its varied shape:classical (Type I ;56.25 %), short triangular (Type II ;21.87%), elongated triangular (Type III;12.5%) and quadrangular(Type 1V;6.25 %) respectively. In one specimen, the VF was deviated to the left side (type V ;3.12%). The mean lengthand width of the fossa were 1.67±0.34 cm and 1.80±0.34 cm respectively.Conclusion: The present study on the morphology and morphometry of the IOC and the VF may serve as databaseand further help clinicians to improve the diagnosis and therapeutic performances in the posterior cranialfossa.

Morphometric Study Of Foramen Magnum Of Skull In Population Of Uttar Pradesh

Background: Foramen Magnum (FM) is a latin word meaning the largest aperture in the base of the skull. It is ovaland wider behind, with the greatest diameter (dm) being antero-posterior (AP). The major vital neuroanatomicpasses through this largest foramen. Many authors have classified FM depending upon its shapes.Objectives: To determine the morphometric parameters of Foramen MagnumMaterials and Methods: The study was conducted on 71 dry human skulls of unknown sex and measured itsAntero-Posterior, Transverse, Right Oblique and Left Oblique diameters with the help of digital caliper.Result: The dormancy of Oval shaped Foramen Magnum was found in this study. The range of Antero-posteriorand Transverse diameter falls between 30.22-40.9 mm and 22.67-33.36 mm respectively. The range of Rightoblique and Left Oblique diameter was found in between 20.84-35.52 mm and 28.88-35.47 mm respectively.Conclusion: The present study will useful not only for anatomists but also in neurosurgery. As the nomenclatureof the opening in the occipital bone at the base of the skull and bounded by Oval and Rounded on visualizationsupported by Antero-Posterior and Transverse diameter of the opening.