It usually collects tributaries from corpus calossum and singulate gyrus regions, and drains into the straight sinus. The inferior sagittal sinus is smaller and inconstant. The frequent variations at the torcular region bear witness to its late embyologic formation from the primordial venous plexus, substantially after the anterior and middle sinus have been formed. Often the SSS divides before reaching the torcula, an anatomical variant of no clinical significance but sometimes leading to unnecessary imaging to “conclusively” rule out an imaginary thrombus. The superior sagittal sinus is nearly always present but can be variable in its anterior extent its hypoplasia may be associated with dominance of the cavernous sinus draining the frontal lobes, prominence of normally small inferior sagittal sinus or large emissary veins - remember the rivers analogy. The more one thinks of the dura not reading the book on where the classic sinuses should be, the easier comprehension of variants becomes and the better the complete venous picture is understood. Apart from the usual sinuses we will discuss, this page illustrates a tremendously rich spectrum of dural venous channels. The other point, no less important, is that the entire dura is a “tabula rasa’ for venous flow. Nearly all variations in venous size can be explained by this simple and powerful analogy. The size of any vein or sinus is determined by the sum total of the tributaries it gathers, much like a river is exactly as large as the total volume of streams which feed it. The most important feature regarding venous sinuses, and veins in general, is to keep in mind that veins are like rivers.
0 kommentar(er)
