The parasellar dura mater and adjacent dura: a microsurgical and light microscopic study in fetal materials

Introduction The external membrane which invests the brain is called the cranial dura mater. It consists of a periosteal layer, which is rich in blood and lymphatic vessels and nerves, and an inner layer named the meningeal layer. At certain places the periosteal and meningeal layers are separated to form the dural venous sinuses. This is the typical description of the cranial dura mater [1–15]. As for localization, cranial dura mater may be roughly divided as the dura of the calvaria and the dura of the skull base, but concerning the adjacent structures it may be divided to the dura of the small wing, the dura of the clivus, the dura of the parasellar region etc. In literature, further attention was given to the parasellar dura mater than the other parts, and special interest was given to the cavernous sinus, as a part of the parasellar dura mater. In fact, many pathological processes are located in the parasellar region [14, 16–20]. In accordance with other authors [1, 7–14, 18–19, 21–22], we define the parasellar dura mater as the part which extends along to the lateral side of the body of the sphenoid bone. Also, it extends anteriorly to the superior orbital fissure, and to the level of the apex of the petrous bone posteriorly. The frontier between the parasellar dura mater and the adjacent dura mater is forms a line starting from the lateral end of the superior orbital fissure and passes through the lateral edge of the foramen rotundum, foramen ovale and foramen lacerum. The internal carotid artery and its sympathetic plexus use the parasellar dura mater as a milieu through which travel from the extradural space to the intradural space. On the other hand, some cranial nerves and some special venous canals use the parasellar dura mater as a milieu through which travel from the intradural space to the extradural space. In literature, we didn’t find any comparison between the description of the structure of the dura mater of the parasellar region and the dura mater of the middle cranial fossa, which is just near to the parasellar region. Is there any difference between the parasellar dura mater and the dura mater of the other cranial regions, or are they completely the same? The aim of this study is firstly to point out the difference between these two. Also, we would like to list and demonstrate our findings on the disposition of the components passing through the parasellar dura mater as the cranial nerves and their vessels, the internal carotid artery and its parasellar branches, which is very important in surgery. Especially, we would like to report our histological and dissection findings on the venous spaces which form the famous cavernous sinus. The parasellar dura mater and adjacent dura: a microsurgical and light microscopic study in fetal materials