Sylvian fissure

Hyperdense embohc material in a more distal MCA branch, within the Sylvian fissure and oriented perpendicular rather than parallel to the axial plane of imaging, may appear as a small, rounded hyperdensity ( MCA dot sign, Fig. 2.1b). One... 

Barher PA, Demchuk AM, Hudon ME, Pexman JH, HiU MD, Buchan AM. H3fperdense Sylvian fissure MCA dot sign a CT marker of acute ischemia. Stroke 2001 32 84-88. 

The middle cerebral artery (MCA) is divided into four segments. The horizontal Ml segment reaches laterally to the bifurcation or trifurcation, the insular segments within the Sylvian fissure are named... 

Bartley AJ, Jones DW, Torrey EF, Zigun JR, Weinnberger DR. 1993. Sylvian fissure asymmetries in monozygotic twins A test of laterality in schizophrenia. Biol Psych 34 853-863. Beasley CL, Chana G, Honavar M, Landau S, Everall IP, et al. 2005. Evidence for altered neuronal organisation within the planum temporale in major psychiatric disorders. Schizophr Res 73(1) 69-78. 

Falkai P, Bogerts B, Greve B, Pfeiffer U, Machus B, et al. 1992. Loss of sylvian fissure asymmetry in schizophrenia. A quantitative post mortem study. Schiz Res 7 23-32. Falkai P, Bogerts B, Schneider T, Greve B, Pfeiffer U, et al. 1995. Disturbed planum temporale asymmetry in schizophrenia. A quantitative post-mortem study. Schiz Res 14 161-176. 

Selemon LD, Rajkowska G, Goldman-Rakic PS. 1998. Elevated neuronal density in prefrontal area 46 in brains from schizophrenic patients Application of a three-dimensional stereologic counting method. J Comp Neurol 392 402-412. Shapleske J, Rossell SL, Simmons A, David AS, Woodruff PW. 2001. Are auditory hallucinations the consequence of abnormal cerebral lateralization A morphometric MRI study of the sylvian fissure and planum temporale. Biol Psychiatry 49(8) 685-693. 

Witelson SF, Kigar D.L. 1992. Sylvian fissure morphology and asymmetry in men and women Bilateral differences in relation to handedness in men. J Comp Neurol 323 326-340. 

The middle cerebral artery enters the Sylvian fissure and divides into two to four branches, which supply the lateral parts of the cerebral hemisphere. From its main trunk, a medial and lateral group of tiny lenticulostriate arteries and arterioles pass upwards to penetrate the base of the brain and supply the basal ganglia and internal capsule (Marinkovic et al. 1985). Some of these small penetrating vessels extend up into the white matter of the corona radiata in the centrum semiovale towards the small medullary perforating branches of the cortical arteries coming down from above. 

Approximately 85% of spontaneous SAHs are caused by ruptured aneurysm 10% are perimesencephalic and the remainder are caused by rare disorders (van Gijn and Rinkel 2001). The pattern of bleeding on CT is a clue to the underlying cause. Blood in the interhemispheric fissure suggests an anterior communicating artery aneurysm and in the sylvian fissure suggests internal carotid artery or middle cerebral artery aneurysm (Fig. 30.1). 

The middle cerebral artery, which originates at the division of the internal carotid artery, passes through the lateral sulcus (Sylvian fissure) en route to the lateral convexity of the cerebral hemisphere, to which it supplies blood. The middle cerebral artery travels along the surface of the insular cortex, over the inner surface of the frontal, temporal, and parietal lobes, and appears on the lateral convexity. The posterior cerebral arteries originate at the bifurcation of the basilar artery, and each one passes around the lateral margin of the midbrain. 

Aboitiz F, Scheibel AB, Zaidel E (1992) Morphometry of the Sylvian fissure and the corpus callosum, with emphasis on sex differences. Brain 115 1521-1541. 

It is well known that sino-venous thrombosis can cause atypical intracerebral hemorrhage (Pradhan et al. 2007 Wang et al. 2007 Spitzer et al. 2005 Oppenheim et al. 2005). Under rare circumstances, however, thrombosis of the superior sagittal sinus can cause pure subarachnoid hemorrhage without intraaxial bleeding. Mostly, SAH is then located at the Sylvian fissure, probably due to dilated Sylvian veins, and in the parietal sulci. 

Fig. 10.7. a,b NECT of a patient with SAH (Fisher°4) with massive subarachnoidal haemorrhage at the Sylvian fissures, perimesencephalic and at the tentorium (arrows). Intraventricular blood clots (arrowheads) and aneurysm surrounded... 

Fig. 4 A. Exploration of the right Sylvian fissure medial to the Sylvian vein (small arrows). The incision (arrow) is in the inferior portion of the insular sulcus, just medial to the superior temporal gyrus and lateral to the inferior trunk of the middle...

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