Wall Of Skull Research Articles

Computerized tomography assessment of calvarial wall thickness in different gender and age in neurosurgical practice- A single centre study

Introduction: Computed tomography (CT) scan has revolutionized the imaging and is gold standard in diagnosis of calvarium thickness. This could help in identifying the racial and the gender variations in calvarial thickness in a population.1 It is helpful for neuroendoscopic procedures to assess size of burrhole in relation to site. Objective of our study: To identify the gender and age variations of calvarial thickness in a given population. To assess the thickness of the various parts of the skull i.e frontal, parietal and occipital bones by computed tomography Materials and Methods: A total of 166 cases, with 71 males and 95 females were selected for the study after meeting inclusion criteria. Thickness of the calvaria was measured over bone windows obtained from computed tomography of brain. Results: We found the superior occipital bone to be thicker in females than males, and inferior occipital bone thicker in males than females which was statistically significant in our study. The overall thickness of the other part of the skull is thicker in females compared to males and right frontal and left parietal is thicker in both the gender but is statistically non- significant. Conclusion: In our study, overall calvarial thickness is greater in females, but in superior occipital region, female skull is thicker and in inferior occipital region, male skull is thicker which is statistically significant and also showed that there is no correlation with age and sides of the skull. Our interpretation did not correlate with the older literature, who interpreted that male skull wall is thicker than females. Keywords: Computed tomography, Calvarium thickness, Frontal bone, Parietal bone, Occipital bone.

The Measurement of Various Anatomical Structures and Assessment of Morphometric Development of Fetal Skull Base.

As the skull base has a complex anatomy, we underline the importance of anomalies for side asymmetry. It is useful to investigate relationship between anatomical structures for the surgical procedure orientations. Dural adherence, enlarged superior petrosal sinus, influence of neural crest cells, and cranial base ossification are among the factors in morphometric growth on skull base. Twenty-five fetuses of an estimated gestational age ranging from 17 to 34 weeks were studied in the Anatomy Laboratory of Mersin University Medical Faculty. Craniotomy was made to each fetus and brain hemispheres were dissected. We put plates, passing from the external points of lateral and anterior-posterior borders of fetus heads that are perpendicular to each other. An analytical calculation was formulated for the angle of foraminae to the root of zygoma by using different formulations depending on their posterior or anterior location to the root of zygoma. Statistical method was based on correlation analysis, simple regression, independent 2 group t tests, SPSS20.0, and MedCalc 11.5 (MedicReS, New York, NY). Neither side dominance for the jugular foramen, nor the differences of foramen rotundum, spinosum, and ovale to anterior skull wall, root of zygoma, and to midline were found to be significant. There is a debate on asymmetry of foramina of the skull base. No certain consensus about the initiation time and the causes of asymmetry in the past was documented. Studies are to be encouraged to further enlighten pre-postnatal factors affecting the fetal skull base morphometrism.

A systematic review of cetothere baleen whales (Cetacea, Cetotheriidae) from the Late Miocene of Crimea and Caucasus, with a new genus

AbstractNine taxa of Miocene baleen whales were described from the Black Sea region under the name Cetotherium before 1951, and a further four closely related species representing three genera have been added in recent years. This rich diversity requires taxonomic revision and ordering. Here, a new genus, Mithridatocetus, is described from the Tortonian of Crimea and Caucasus, with two species, M. eichwaldi and M. adygeicus (originally Kurdalagonus adygeicus); ‘Cetotherium’ mayeri (a nomen dubium) is also a member of this genus. In comparison with other Cetotheriinae, Mithridatocetus is distinguished by the autapomorphic shape of the tympanic bulla with the swollen main ridge, the lowered anterior portion of the involucrum and the oblique anterolateral margin; such synapomorphies, as a transversely narrow squamosal with the ventromedially oriented postglenoid process (shared with Eucetotherium), a squamosal cleft (shared with Kurdalagonus) and an oval surface of the compound posterior process of the tympanoperiotic on the posterolateral skull wall (shared with Brandtocetus); and a unique combination of a high neurocranium and a long and robust paroccipital process. The genus Kurdalagonus is redefined here as containing only one described species, K. mchedlidzei. Therefore, the group Cetotheriinae is now restricted to the latest Serravallian and Tortonian of the Eastern Paratethys and includes at least five genera: Cetotherium, Brandtocetus, Kurdalagonus, Mithridatocetus and Zygiocetus. In addition, ?Cetotherium priscum and C. incertum are considered to be nomina dubia; ‘Cetotherium’ klinderi and ‘Cetotherium’ pusillum require more complete specimens for reassessment; ‘Cetotherium’ maicopicum and Eucetotherium helmersenii require further research to identify their taxonomical affinities.

Morphological Variations in the Transverse Venous Sinus Anatomy of Dogs and its Relationship to Skull Landmarks.

We characterized the anatomical morphology of the transverse venous sinus (TVS) of 69 canine adult cadavers belonging to three groups: brachycephalic (B), dolichocephalic (D) and mesaticephalic (M). In addition, we outlined its path over the skull using five classic human craniometric points (CPs): the asterion (ast), the bregma (b), the glabella (g), the stephanion (st) and the pterion (pt). The study aimed to establish anatomical differences in the TVS between groups and in the relationship between the TVS and skull. We found that TVS anatomy and its relationships to skull landmarks vary markedly between the groups, with similar anatomical arrangements in B and M. The TVS length can be ranked as M<B<D (with D being the biggest), whereas the width can be ranked as M<D<B (with B being the widest) with the right side being smaller than the left. In the B and M groups, the TVS assumes a craniocaudal trajectory that is closer to the lateral skull wall than in D, where the TVS presents a caudocranial direction. By documenting the morphological characteristics of the TVS, we can create a set of anatomical references allowing construction of a basic framework to greatly decrease the probability of TVS injury during neuronavigation procedures when supported by a good knowledge of the skull, brain anatomies and their relationships.

Characterization of Ultrasound Propagation Through Ex-vivo Human Temporal Bone

Adjuvant therapies that lower the thrombolytic dose or increase its efficacy would represent a significant breakthrough in the treatment of patients with ischemic stroke. The objective of this study was to perform intracranial measurements of the acoustic pressure field generated by 0.12, 1.03 and 2.00-MHz ultrasound transducers to identify optimal ultrasound parameters that would maximize penetration and minimize aberration of the beam. To achieve this goal, in vitro experiments were conducted on five human skull specimens. In a water-filled tank, two unfocused transducers (0.12 and 1.03 MHz) and one focused transducer (2.00 MHz) were consecutively placed near the right temporal bone of each skull. A hydrophone, mounted on a micropositioning system, was moved to an estimated location of the middle cerebral artery (MCA) origin, and measurements of the surrounding acoustic pressure field were performed. For each measurement, the distance from the position of maximum acoustic pressure to the estimated origin of the MCA inside the skulls was quantified. The −3 dB depth-of-field and beamwidth in the skull were also investigated as a function of the three frequencies. Results show that the transducer alignment relative to the skull is a significant determinant of the detailed behavior of the acoustic field inside the skull. For optimal penetration, insonation normal to the temporal bone was needed. The shape of the 0.12-MHz intracranial beam was more distorted than those at 1.03 and 2.00 MHz because of the large aperture and beamwidth. However, lower ultrasound pressure reduction was observed at 0.12 MHz (22.5%). At 1.03 and 2.00 MHz, two skulls had an insufficient temporal bone window and attenuated the beam severely (up to 96.6% pressure reduction). For all frequencies, constructive and destructive interference patterns were seen near the contralateral skull wall at various elevations. The 0.12-MHz ultrasound beam depth-of-field was affected the most when passing through the temporal bone and showed a decrease in size of more than 55% on average. The speed of sound in the temporal bone of each skull was estimated at 1.03 MHz and demonstrated a large range (1752.1 to 3285.3 m/s). Attenuation coefficients at 1.03 and 2.00 MHz were also derived for each of the five skull specimens. This work provides needed information on ultrasound beam shapes inside the human skull, which is a necessary first step for the development of an optimal transcranial ultrasound–enhanced thrombolysis device. (E-mail: Christy.Holland@uc.edu)

Francesco Rizzoli (1809–1880) and the elusive case of Giulia: the description of an “arteriovenous aneurysm passing through the wall of the skull”

The improved knowledge of the clinical and haemodynamical aspects of extracranial arteriovenous malformations in the 18th century provided a foundation for the understanding and treatment of cerebrovascular pathology. It was not until the late 19th century that detailed clinicopathological reports of intracranial arteriovenous malformations were published. A seminal report by the Italian surgeon Francesco Rizzoli described Giulia, a 9-year-old girl who presented with seizures and an occipital pulsanting swelling in 1873. Rizzoli used Giulia's signs and symptoms to predict the complex angioarchitecture of her "arteriovenous aneurysm passing through the wall of skull". Postmortem examination confirmed the supposed diagnosis, and showed a direct communication between the hypertrophic branches of the ocipital artery and the transverse sinus. The clinical course of that case is briefly reviewed in this article and the diagnosis of this unusual arteriovenous shunt is discussed in light of current neurosurgical knowledge.

Le refroidissement sélectif du cerveau

The brain is especially sensitive to heat stress. To limit the increase of intracranial heat in case of hyperthermia or fever, a system of selective cooling is put on. It includes two heat-exchangers. The first one, in the face and scalp skin, disperses calories through sweat evaporation. The second one is intracranial, close to the arteries which irrigate the brain. They are connected by a vascular network. In these conditions, the arterial blood temperature, of which cerebral temperature depends upon, is reduced by the cooled venous blood which comes from subcutaneous tissues through the skull wall. On feverish children, increasing such a selective cooling by face fanning can limit cerebral thermal stress.