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Abstract In this paper, we present the results of our investigations on the neuro-arterial relations in the region of the optic canal. A thorough knowledge of the microanatomic features of the ophthalmic artery, optic canal and optic nerve is very important for surgeons approaching lesions of this area. We aimed to extend our present knowledge of the origin of the ophthalmic artery and microsurgical anatomy of the optic canal with exposure of the optic nerve. The optic canal walls and width and height of the orbital and cranial apertures, and thickness of the bony roof of the optic canal were measured on the right and left sides of 57 sphenoid bones, 102 skull bases and 58 fixed adult cadaver heads. The ophthalmic artery originated from the rostromedial circumference of the internal carotid artery in 51.8%, from the medial circumference in 26.2% and the laterobasal circumference in 22% of the specimens. The outer diameter of the ophthalmic artery at its origin was 1.81 ± 0.36 mm on the right and 1.75 ± 0.37 mm on the left side.

Abstract The microsurgical anatomy of the cavernous sinus of 54 Turkish adult cadaveric heads (108 specimens) was examined to provide data for major topographic aspects and morphometry of the region, which is of special clinical importance for neurosurgeons. Significant findings were 1) the abducent nerve in the cavernous sinus was observed as one rootlet in most of the specimens (78%), two rootlets in 14%, three in 5% and four in 3% of the specimens 2) the anterior inferior venous space was dominant in 58%, the posterior superior venous space in 16%, and an intermediate type in 29% of the specimens 3) the artery of the inferior cavernous sinus originated from the internal carotid artery (ICA) in 74% of the cases, and 4) the dorsal meningeal artery originated from the ICA in 6 (5.5%) of the specimens.

Abstract Topographic landmarks for the superior orbital fissure are useful for general orientation and approach to the middle fossa, cavernous sinus and orbit. In this study, the microsurgical anatomy and morphometry of the superior orbital fissure and its related structures were examined in 57 disarticulated sphenoid bones, 102 skull bases and 58 adult cadaveric heads. The superior orbital fissure was observed in nine different shapes based on the classification of Sharma et al. (1988), and the most frequently observed was Type VI. The distance from the superomedial to the superolateral edge was measured as 17.3 ± 3.4 mm on the right side and 16.9 ± 2.9 mm on the left side, and from the superolateral to the inferior edge as 20.8 ± 3.9 mm on the right side and 20.1 ± 3.8 mm on the left side. The distance from the superomedial to the inferior edge of the fissure was measured as 9.5 ± 2.2 mm on the right side and 9 ± 2.4 mm on the left side. No right-left differences were observed for these measurements. Measurements regarding the relationship of the oculomotor, trochlear and abducent nerves, the ophthalmic branch of the trigeminal nerve and the superior orbital vein were performed and topographic aspects of the superior orbital fissure region were described.

NADPH-diaphorase-containing neurons (it is supposed that this enzyme is a form of NO-synthase, NOS) were histochemically identified in the spinal cord of rats. In another set of the experiments, we identified neurons -sources of spinothalamic and spinomesencephalic pathways - by their retrograde labelling with Fluoro-Gold (FG) injected into the thalamus and periaqueductal gray substance. It was shown that NOS-containing spinal cells are, as a rule, propriospinal intersegmental or intrasegmental interneurons. We discuss the possible involvement of these cells in the “inhibition-of-inhibition” processes and in potentiation of the synaptic transmission in spinal neurons under conditions of the development of tonic or chronic pain. In rats, the number of NOS-containing neurons, which are also retrogradely labelled with FG after dye injection into the thalamus and midbrain, Is rather limited.

The laminar distribution of spinomesencephalic, spinothalamic, and spinotelencephalic tract neurons, and the pattern of axonal collateralization in these spinocerebral pathways were studied in the rat by means of retrograde double-labelling of the cells with fluorescent dyes Fluoro-Gold and Primuline O. We found that sources of spinocerebral pathways to the analgesic brainstem centers, as well to thenucl. accumbens and septal nuclei, were mixed together in the marginal zone (lamina I, by Rexed), in the deep dorsal horn (laminae IV–VI), in the area around the central canal (lamina X), and within the lateral spinal nucleus. At the same time, all the above pathways retain their own specific projection fields. Thus, these spinocerebral projections could be characterized as extensive, but not diffuse. We propose that the main effect of activation of the direct spinal inputs to the limbic system is an increase in nociceptive sensitivity, but not a suppression of nocicptive transmission at the the spinal cord level.

Abstract A study was undertaken to demonstrate the variational anatomy of the external aperture of the vestibular aqueduct in 90 human temporal bones obtained from 58 cadavers. Topographic landmarks of the posterior surface of the petrous bone are useful for general orientation and include the external aperture of the vestibular aqueduct, internal auditory meatus, sigmoid sinus, subarcuate fossa, superior petrosal sinus and cochlear canaliculus. We determined the mean distances from the external aperture of vestibular aqueduct to the above structures to be 10.98, 11.21, 9.42, 10.27 and 13.90 mm, respectively. Furthermore, the length of the external aperture of the vestibular aqueduct revealed significant differences between the right and left sides. The distances between the EAVA and certain anatomical structures on the posterior surface of the temporal bone should be taken into consideration during surgery. Knowing the variability of the position of the external aperture of the vestibular aqueduct may help surgeons avoid traumatizing, and thus producing inadvertent lesions to the hearing mechanism.