Abstract:

Objective　To investigate the microsurgical anatomic features and clinical significances of the posterior communicating artery cistern (PComA cisterns) and associated arachnoid membranes.　Methods　10 cases（20 sides ）of formalin-fixed cadaveric head specimens were microdissected to observe structures of PComA cistern and related arachnoid membranes under the operating microscope.　Results　The frequency rate of PComA cistern was about 60% (12 sides from all of specimens).The anterior wall of the cistern was the posterior communicating membranes. The carotid cistern directly communicated with the PComA cistern in the absence of the posterior communicating membranes. The posterior wall of the cistern was  diencephalic and mesencephalic leaves of liliequist membranes. The medial wall was the carotid membranes and the lateral wall of diencephalic and mesencephalic leaves of liliequist membranes. The anterolateral wall was the lateral carotid membranes or the medial temporal lobe, and the posterlaeral wall the arachnoid trabeculaes arising from mesencephalic leaves of liliequist membranes which attached to the oculomotor nerve and posterior communicating artery. The superior lateral wall was incrual membranes, and the bottom wall the arachnoid membranes of base skull and diencephalic leaves of liliequist membranes. The features of different membranes were distinct.　Conclusions　This study identifies the features of the PComA cistern and associated arachnoid membrane, which is a valuable reference for clinic application.

Key words: Cisterns, Arachnoidal membranes, Microanatomy, Neurosurgery