Morphometric assessment methods for estimation of sexual dimorphism from cranial occipital condyles / Métodos de evaluación morfométrica para la estimación del dimorfismo sexual de los cóndilos occipitales craneales

SUMMARY: Identification of fragmentary human remains is an integral par of medico legal investigations. Occipital region is commonly not affected in traumatic injuries and accidents due to its secluded position which makes it the integral part in determination of sex in the absence of entire skeleton. Occipital condylar region is also the most common area for degenerative and neoplastic diseases. So thorough knowledge of anatomy of occipital condyle is very essential during surgical interventions. 86 skulls were studied from osteological collections of Department of Anatomy, Yenepoya Medical College. Maximum length and breadth of the occipital condyle, anterior intercondylar distance and posterior intercondylar distance was measured with the help of vernier callipers. Descriptive statistics was calculated for the parameters considered. Metric data of right and left sides were compared with student t test and p value was calculated.All data obtained was subjected for discriminant function analysis to derive the statistical model. All the measurements were significantly high in males compared to females. Condylar length and width, anterior and posterior intercondylar distance can be used to derive formula for determination of sex in south Indian population with an accuracy of 66.3 %.

RESUMEN: La identificación de restos humanos fragmentarios es una parte integral de las investigaciones médico legales. La región occipital comúnmente no se ve afectada en lesiones traumáticas y accidentes debido a su posición apartada que la convierte en parte integral en la determinación del sexo en ausencia de un esqueleto completo. La región condilar occipital es también el área más común de enfermedades degenerativas y neoplásicas. Por lo tanto, el conocimiento integral de la anatomía del cóndilo occipital es esencial durante las intervenciones quirúrgicas. Se estudiaron 86 cráneos de colecciones osteológicas del Departamento de Anatomía, Facultad de Medicina de Yenepoya. Se midió el largo y ancho máximo del cóndilo occipital, la distancia intercondilar anterior y la distancia intercondilar posterior con la ayuda de un calibrador vernier. Se calculó la estadística descriptiva para los parámetros considerados. Los datos métricos de los lados derecho e izquierdo se compararon con la prueba t de Student y se calculó el valor de p. Todos los datos obtenidos se sometieron a análisis de función discriminante para derivar el modelo estadístico. Todas las medidas fueron significativamente altas en los hombres en comparación con las mujeres. La longitud y el ancho del cóndilo, la distancia intercondilar anterior y posterior se pueden utilizar para derivar la fórmula para determinar el sexo en la población del sur de la India con una precisión del 66,3 %.

A virtual assessment of the suprainiac depressions on the Eyasi I (Tanzania) and Aduma ADU-VP-1/3 (Ethiopia) Pleistocene hominin crania.

Despite a steady increase in our understanding of the phenotypic variation of Pleistocene Homo, debate continues over phylogenetically informative features. One such trait is the suprainiac fossa, a depression on the occipital bone above inion that is commonly considered an autapomorphy of the Neanderthal lineage. Challenging this convention, depressions in the suprainiac region have also been described for two Pleistocene hominin crania from sub-Saharan Africa: Eyasi I (Tanzania) and ADU-VP-1/3 (Ethiopia). Here, we use a combined quantitative and qualitative approach, using µCT imaging, to investigate the occipital depressions on these specimens. The results show that neither the external nor the internal morphologies of these depressions bear any resemblance to the Neanderthal condition. A principal component analysis based on multiple thickness measurements along the occipital squama demonstrates that the relative thickness values for the internal structures in Eyasi I and ADU-VP-1/3 are within the range of Homo sapiens. Thus, our results support the autapomorphic status of the Neanderthal suprainiac fossa and highlight the need to use nuanced approaches and multiple lines of evidence.

A virtual assessment of the proposed suprainiac fossa on the early modern European calvaria from Cioclovina, Romania.

OBJECTIVES: The calvaria from Cioclovina (Romania) has been argued to possess some traits commonly ascribed to individuals belonging to the Neanderthal lineage, including a suprainiac fossa. However, its supranuchal morphology has only been evaluated with a qualitative analysis of the ectocranial surface. We evaluate whether the morphology of the supranuchal area of this specimen is homologous to the Neanderthal condition. MATERIALS AND METHODS: We described in detail the external morphology, and, using computed tomography, investigated the internal morphology of the Cioclovina supranuchal area. We took measurements of the internal structures and calculated their relative contributions to total cranial vault thickness, which were compared to published data and evaluated with a principal component analysis (PCA). RESULTS: The Cioclovina supranuchal region is characterized by superficial resorption present on the outer layer of the external table. Neither the diploic layer nor the external table decrease in relative thickness in the area above inion. In the PCA, Cioclovina falls within the convex hulls of recent modern Homo sapiens. DISCUSSION: Our results show that the morphology of the Cioclovina supranuchal region does not correspond to the external and internal morphology of the typical Neanderthal suprainiac fossa. It cannot be characterized as a depression but rather as an area presenting superficial bone turnover. Together with earlier results, there is little phenotypic evidence that Cioclovina has high levels of Neanderthal ancestry. Our study demonstrates the usefulness of this quantitative method in assessing proposed Neanderthal-like suprainiac depressions in Upper Paleolithic and other fossil specimens.

Comparative morphology and morphometric assessment of the Neandertal occipital remains from the El Sidrón site (Asturias, Spain: years 2000-2008).

This paper analyses the occipital remains recovered from the El Sidrón (Asturias, Spain) Neandertal site between the years of 2000-2008. The sample is represented by three specimens, SD-1219, SD-1149, and SD-370a. Descriptive morphology, linear measurements, 3D geometric morphometrics, and virtual anthropological methods were employed to address the morphological, morphometric, and phylogenetic affinities of these fossils. The fossils display Neandertal autapomorphies (e.g., bilaterally protruding transverse occipital torus, suprainiac fossa). SD-1219 also preserves a strongly projecting juxtamastoid eminence and shows occipital bunning. In linear distances, the El Sidrón occipitals are similar to each other and close to the Neandertal mean. The centroid size of SD-1219 is slightly larger than the Neandertal average. All of the evidence taken together points to the hypothesis that SD-1219 belongs to a smaller Neandertal male. Linear measurements and the vault thickness of SD-1149 also suggest a robust male individual. The gracility of SD-370a points towards an immature individual. Virtual anthropological methods were used to reconstruct a 3D model of the SD-1219 occipital for geometric morphometrics, which reveals that SD-1219 shows relatively broad and low occipital plane proportions. Within the European Pleistocene lineage sample, this fossil falls geometrically closer to primitive rather than to derived morphologies because of its increased width, and a lower, anterior position of inion relative to the biasterionic axis. These results may imply that cranial sphericity could be an important feature of intraspecific Neandertal variability. Our findings open the way for further studies of intraspecific variation in Neandertal populations, in which the El Sidrón sample may play a significant role.

[Microsurgical anatomy and quantitative assessment of suboccipital median transcerebellomedullary fissure keyhole approach].

OBJECTIVE: To assess the suboccipital median transcerebellomedullary fissure keyhole approach in a cadaver model by using a neuronavigation system and explore its feasibility and operative indications. METHODS: Six 10% formaldehyde-fixed adult cadaveric head and neck specimens injected with colored latex were chosen for the study. First the suboccipital median transcerebellomedullary fissure keyhole approach was performed and the anatomical structures were observed under operative microscope. The exposed floor area of the fourth ventricle and the vertical and transverse angles at the point where the line between the lateral apertures crossing the median sulcus, vertical angle at the apertures of midbrain aqueduct and the obex were measured with the aid of a frameless stereotactic navigation device. Parameters were compared with those when C1 posterior arch was removed, and also with those under conventional approach with or without C1 arch. RESULTS: By means of adjusting specimen positions and the angle of operative microscope, as tela choroidea and inferior medullary velum were dissected gradually, the structures of floor, lateral recesses and lateral apertures of the fourth ventrical, vermian and aperture of midbrain aqueduct were exposed. There were no significant difference in the exposed floor area of the fourth ventricle between the keyhole approach and conventional approach (P = 0.06), and the C1 arch removal can't increase the exposed area (P = 0.84). The conventional approach have wider angles than the keyhole approach (P < 0.01), and the C1 arch removal increased the vertical angle (P < 0.05), but not the horizontal angle (P > 0.05). CONCLUSION: The suboccipital median transcerebellomedullary fissure keyhole approach can expose similar anatomic architectures as that of the conventional approach. Thus it can be used to remove the tumors located in the fourth ventricle, dorsum of pons and medullary oblongata and cerebellar vermis.

Cephalometric superimposition on the occipital condyles as a longitudinal growth assessment reference: I-point and I-curve.

This retrospective study tests the hypothesis that superimposition referenced at the occipital condyles (defined as I-point, I-curve) and oriented to the anterior cranial base (ACB) will display a growth pattern that is more consistent with independent evaluations, such as the Melsen necropsy specimens and the Bjork implant studies, when compared with traditional superimpositions referenced at sella turcica. Twenty-eight sets of serial lateral cephalometric radiographs were selected from an archived growth study. The apparent facial growth was compared using polar coordinate analysis from superimposition tracings of the serial films for each subject. The two superimposition methods were compared. The traditional method, ACB registered on the anterior curvature of sella turcica, versus registration on I-point while maintaining ACB parallel. I-point registered superimpositions consistently displayed a facial growth pattern that was more consistent with the classic necropsy specimens of children and the cephalometric studies superimposing on implant markers. Traditional ACB superimposition suggests that airway is restricted by normal growth. This apparent physiologic artifact does not occur when superimpositions are registered on I-point. Sella turcica displays vertical movement that is consistent with brain growth. These data indicate that registration on I-point is a more accurate physiologic representation of facial growth than the traditional ACB superimpositions. When compared with the traditional registration at sella turcica, I-point superimposition better elucidates physiologic growth patterns. As cephalometrics evolve from a two to a three dimensional science, it is important to use a more biologically valid registration for evaluating therapeutics and facial growth patterns.

Morphological assessment of craniovetebral junction development in the prenatal period.

BACKGROUND: Because of numerous abnormalities of craniovertebraljunction development observed in the prenatal period, the region has been studied thoroughly in order to elucidate the mechanism of axial differentiation, dependence of vertebral morphology on the development of ossification centers and the mechanisms regulating the dynamics of growth. AIM: Analysis of morphological changes of the craniovertebral junction taking place during the prenatal period by quantitative assessment of some developmental changes such as growth rate, sexual dimorphism, interdependence of the analyzed parameters, taking into consideration the variable geometry of the studied area. MATERIAL/METHODS: he study was carried out on 48 fetuses (22 male, 26 female) of 86-212mm crown-rump length (CRL) range. The applied methods included: anthropometry, precise measurements, as well as trigonometric calculation of angles. RESULTS: All the investigated parameters demonstrated a strong, statistically significant correlation with CRL. No statistical significance of sexual dimorphism and differences between left- and right-sided measurements was demonstrated. The development rate indexes for the height of C1,C2 posterior vertebral arches, unlike those for the transversal dimensions of C1,C2 posterior vertebral arches, decrease after 5 months of gestational age. Little variability of the angles determined by geometrical reconstruction evidences close interdependence in the development of the analyzed craniovertebral junction elements. CONCLUSIONS: Geometrical configuration of the craniovertebraljunction during the fetal period is constant, with growth isometry preserved throughout intrauterine development. The occipital bone and Cl,1C2 cervical vertebrae are closely correlated according to structural and functional dependences.

A quantitative assessment of the jugular foramen.

While it is generally accepted that the right jugular foramen is larger than the left, little quantitative evidence exists on the exocranial and endocranial openings of this foramen. The present study set out to clarify and quantify measurements of the two openings. The dimensions of the exocranial and endocranial openings of the jugular foramen and the volume and height of the jugular fossa were examined in a total sample of 93 skulls from white and black, male and female South Africans. The volume of the jugular fossa was determined with the use of a dental impression material. The exocranial area of the right jugular foramen was significantly larger (p < 0.05) than the left in the black group, while the endocranial area of the right foramen was significantly larger (p < 0.05) than the left only in black males. The height of the jugular fossa was significantly larger (p < 0.05) on the right side only in the black group. The volume of the jugular foramen was significantly larger (p < 0.05) on the right side only in females of both groups. Although the jugular foramen is generally larger on the right side than on the left, its size as well as the volume and height of the jugular fossa is variable in different groups and sexes.

Effects of fronto-occipital artificial cranial vault modification on the cranial base and face.

Artificial reshaping of the cranial vault has been practiced by many human groups and provides a natural experiment in which the relationships of neurocranial, cranial base, and facial growth can be investigated. We test the hypothesis that fronto-occipital artificial reshaping of the neurocranial vault results in specific changes in the cranial base and face. Fronto-occipital reshaping results from the application of pads or a cradle board which constrains cranial vault growth, limiting growth between the frontal and occipital and allowing compensatory growth of the parietals in a mediolateral direction. Two skeletal series including both normal and artificially modified crania are analyzed, a prehistoric Peruvian Ancon sample (47 normal, 64 modified crania) and a Songish Indian sample from British Columbia (6 normal, 4 modified). Three-dimensional coordinates of 53 landmarks were measured with a diagraph and used to form 9 finite elements as a prelude to finite element scaling analysis. Finite element scaling was used to compare average normal and modified crania and the results were evaluated for statistical significance using a bootstrap test. Fronto-occipitally reshaped Ancon crania are significantly different from normal in the vault, cranial base, and face. The vault is compressed along an anterior-superior to posterior-inferior axis and expanded along a mediolateral axis in modified individuals. The cranial base is wider and shallower in the modified crania and the face is foreshortened and wider with the anterior orbital rim moving inferior and posterior towards the cranial base. The Songish crania display a different modification of the vault and face, indicating that important differences may exist in the morphological effects of fronto-occipital reshaping from one group to another.

[Control and regulation of the blood circulation in the vertebro-basilar system. Review of the literature]. / Contrôle e regulação da circulação sanguínea no sistema vértebro-basilar. Revisão de literatura.

The author establishes an analogy between the control mechanism and regulation of the cerebral blood flow and of protection of the vascular wall of the internal carotid constituted by the conjunction "internal carotid-cavernous sinus" with the group represented by the system "vertebro basilar-transverse occipital sinus or basilar" (an extension of the cavernous sinus) in the regulation and control of the encephalic circulation carried out through this latter vessels, together with the protection of its vascular walls. The author believes to be very difficult to demonstrate in practice the functioning of these mechanisms, but it is very logical and easy to reason about them, to value them and to give the importance and meaning or motive which forcibly they should have and not simply consider them as freaks of nature and bizarre anatomical features.