OBJECTIVE. To evaluate the anatomic aspects of the diaphragma sellae and its potential role in directing the growth of a pituitary adenoma.METHODS. Twen

The orbits are paired structures, located on the anterior part of the face. Morphologically, each orbit is a four sided pyramid with a posterior apex and anterior base. In the orbit, all openings are arranged around the base, apex or between the orbital walls. An anatomical characteristic of the orbit is that structures are arranged in groups of seven: there are seven bones, seven intraorbital muscles and seven nerves in the orbit. Tumors confined within the periorbita in the anterior two thirds of the orbit can often be approached extracranially, but those located in the apical area, and especially those on the medial side of the optic nerve, often require a transcranial approach. Thus, knowledge of orbital osteology is paramount in adequately choosing and performing an orbital approach. Understanding the critical topographical elements in this area helps to classify an orbital lesion and provides for a solid basis in choosing the most adequate intraorbital route for its treatment.

Introduction Vascular complications of posterior fossa surgery are often deadly although widely preventable through in-depth knowledge of the microsurgical neurovascular anatomy of the infratentorial region and careful surgical planning. The target of this study is to provide a synoptic overview of the normal anatomy and anatomic variants of the infratentorial neurovascular system, critical to safely operate tumors and neurovascular pathologies of the posterior fossa. Methods Two fresh-frozen and five formalin-fixed cadaveric heads were used. Cervical arteries and internal jugular veins were injected with red and blue latex, respectively. The heads were dissected under a surgical microscope, with magnifications ranging between 3× to 40×, focusing on the infratentorial region. The infratentorial arteries, their collaterals and perforating branches, the brainstem and cerebellar veins, the tentorial venous sinuses, and the relative vascular territories were summarized according to a synoptic approach. Results The vertebral artery, basilar artery (BA), and posterior cerebral artery (PCA) are the main sources of the arterial supply of the brainstem and cerebellum through the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), the superior cerebellar artery (SCA), and the perforating arteries. The perforating arteries of the vertebrobasilar system derive from the PICA, BA, AICA, SCA, and PCA, and provide for a key contribution to the vascularization of the midbrain, pons, medulla oblongata, fourth ventricle, cerebellar and cerebral peduncles, thalamus, hypothalamus, subthalamus, posterior part of the internal capsule, and optic tract. The distal segments and branches of the PCA also add a significant arterial supply to the temporal, occipital, and parietal lobes. The venous outflow of the posterior fossa is a prerogative of the internal jugular veins via the tentorial venous sinuses. Conclusion A perfect mastery of the arterial, venous, and cisternal anatomy of the infratentorial region is vital for the planning and execution of the whole range of posterior fossa approaches.

Diffusion tensor imaging (DTI)-based tractography is a noninvasive in vivo method for tracing white matter bundles. This raises possibilities for qualitative and quantitative assessment of the structural organization of tracts. Nevertheless, questions remain about neuroanatomical accuracy, reproducibility for clinical purposes, and accessibility of the best method for broader application. The aim of this study was to combine the fiber dissection technique and tractography to provide more pertinent insight into brain anatomy and, as a result, to test a protocol for reconstruction of six major frontal lobe tracts. A combination of fiber dissection of formalin-fixed brain tissue after freezing (Klingler's technique) and virtual dissection (tractography) was used to develop a protocol to reconstruct major frontal tracts. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), number of voxels (NVO), volume (VOL), number (NTR), and length (LEN) of tracts were evaluated to assess intra- and interobserver reproducibility. Statistical reliability was evaluated using intraclass correlation coefficients (ICCs) and the Pearson association coefficient (r). The virtual dissection obtained by tractography seemed to reproduce the anatomic knowledge of the white matter tracts obtained through the classic method. In reliability study, most ICC and r values corresponded at least to large correlation. The magnitude of correlation was very high (ICC 0.7-0.9) or almost perfect (ICC 0.9-1.0) for the FA and ADC measures of every tract studied. The DTI protocol proposed herein provided a reliable method for analysis of reconstructed frontal lobe tracts, especially for the FA and ADC variables.