Junction between the great cerebral vein and the straight sinus: an anatomical, immunohistochemical, and ultrastructural study on 25 human brain cadaveric dissections.

The cerebral venous system is poorly understood, and best appreciated under macroscopic anatomical considerations. We present an anatomical and immunohistochemical studies to better define the morphological characteristics of the junction between the great cerebral vein and the straight sinus. Twenty-five cadaveric specimens from the anatomy laboratory of the University Victor Segalen of Bordeaux were studied. The observation of the venous junctions with the straight sinus was performed under an operating microscope. The smooth muscular actin immunohistochemical staining was performed for 18 veno-sinosal junctions. Five venous junctions were observed using an electron microscope. We observed 3 different anatomic aspects: type 1 was a junction with a small elevation in its floor and a posterior thickening (14 cases); type 2 was a junction with an outgrowth on the floor like a cornice (7 cases); and type 3 was a junction presenting a nodule. Microscopic study of type 1 and 2 junctions showed a positive coloration to orceine attesting the presence of elastic fibers. Immunohistochemistry revealed the presence of smooth muscular actin and S 100 protein attesting the presence of smooth muscular fibers and nervous fibers. We observed in the ultrastructural study, a morphological progression of the endothelium. The venous orifice of the great cerebral vein into the straight sinus could be anatomically assimilated as a true "sphincter." Its function in the regulation of the cerebral blood flow needs further exploration.