gms | German Medical Science

Methods: The cavernous sinus (CS) was studied in 16 specimens obtained from 8 cadaver heads fixed in formalin; the arteries and veins were perfused with colored silicon. The specimens were used for microsurgical dissection with an operating microscope under x3 to x40 magnification.

Results: The observations and dissections have confirmed the data known from the Literature and added some new finding:

The endosteal layer of the CS, at the level of the upper border of the maxillary nerve and the lower margin of the carotid sulcus, divides into two layers: one layer adheres to the sphenoid bone, covering the carotid sulcus and the floor of the sella (forming the sphenoid part of medial wall CS), and the other layer extends upward to constitute the internal layer of lateral wall and roof of the CS, the diaphragm sellae and the thin layer of the sellar part of the medial wall of CS. The meningeal layer, that is always situated at the upper border of the maxillary nerve, which is the most inferior limit of CS, extends upward to form the outer part of the lateral wall of the CS, and the upper layer of sinus roof and the diaphragm sellae. The endosteal layer (inner layer - deep layer) was less defined than the superficial layer (meningeal layer) and was more irregular and variable in its texture and morphological characteristics. It was found to be formed by the sleeves or sheaths of dura mater accompanying the corresponding nerves from their points of penetration into the sinus walls.

The upper ring is adherent to the wall of the artery, but the lower ring is separated from the lower margin of the clinoid segment by narrow space that admitted venous tributaries of cavernous sinus, called the clinoid venous plexus. This venous plexus narrowed as the upper ring is approached and becomes wider at the lower ring, where the plexus communicated with the venous channels of the cavernous sinus. The upper and lower dural rings were best defined along the lateral ant the anterior margins of the artery, were less distinct medially, and disappeared posteriorly, where the dura forming the upper and lower rings came together. The clinoid segment is intracavernous, being located within a collar of dura in which venous tributaries of the cavernous sinus course.

Conclusions: Electronical microscopy studies are in progress to better demonstrate that cavernous sinus is situated within the intradural space inside one single layer (the inner layer).