Novel concept of the microanatomy of cavernous sinus

Objective To study the new concept of the microanatomy of cavernous sinus region and provide the detailed anatomical parameters for its operative approach.Methods The microsurgical dissections were performed on formalin-fixed and dye-injected cadaveric heads with the aid of microscope to observe and measure the dura, nerves and vessels in the cavernous sinus region, and to learn the relationships among the dura, nerves and vessels in the cavernous sinus region by histochemical technique.Results In middle cranial fossa, cavernous sinus and relevant anatomical structures were located in a cave made up of two floors of dura, namely dura mater space. Cranial nerves Ⅲ, Ⅳ, Ⅵ, the Meckel's cave, the trigeminal ganglion and its three branches, which were enwrapped by arachnoid and dura, entered among the dura mater space, namely neuro-midriff, and internal carotid artery and some venous structures traveled among them. The dura mater space was divided into three parts by the neuro-midriff: ①The dura fissure: the outer part by which the extradural approach can be performed without the separation of trigeminal nerve branches; ②The blood fissure; ③The clinoid process fissure: located between the anterior clinoid process and the dural plate.Conclusion The study of the microsurgical anatomy of cavernous sinus can provide a new constructive conception about this region, which provides the surgical anatomical basis for the surgical approach.