Cranial arachnoid membranes: some aspects of microsurgical anatomy.
Although the arachnoid membranes have been known for more than 300 years, the anatomy of the arachnoid membranes has not been studied in detail. This study was performed to explore the microanatomical features of the cranial arachnoid membranes. The arachnoid membranes and cisterns were observed in eight Han Chinese adult human cadaveric brains with an operating microscope, without staining of intracranial structures or injection of colored material into blood vessels. Twenty seven arachnoid membranes and 21 subarachnoid cisterns were identified. The topographical features of each arachnoid membrane were described. On the basis of the arachnoid membranes we identified, the arachnoidal limits of the cisterns were discussed. The microsurgical anatomical research on the arachnoid membranes is a supplement to the anatomical study of the subarachnoid cisterns. The understanding of the topographical features of the arachnoid membranes is valuable to the reasonable dissection of the cisterns and the minimally invasive manipulations during microsurgical procedures.