Abstract: Objective: Understanding the microanatomical structures of the trigones related to the cavernous sinus （CS） in order to provide safe operative approaches for direct microsurgical operation to the CS. Methods: Twenty adult cadaver heads were used to anatomize, observe and measure the trigones in three CS walls facing to the brain under microscope. Results: 12 trigones were observed in CS. They were anteromedial trigone, medial trigone, carotid trigone and oculomotor trigone in the superior wall of the CS; Lateromedial trigone, Parkinson trigone, Mullan trigone, lateral trigone, Glasscock trigone and Kawase trigone in/near the lateral wall. Inferolateral trigone and inferomedial trigone in the posterior wall. Conclusion: The trigones of the CS may provide safe approches for direct operation to CS, which can make us do the following good: entering the CS without injuring some important nerves and arteries. Clinicallly, the most used combined approach（Pterional Approach, frontotemperal bone flap used）is throuth the superior and lateral walls of the CS which the midial and Parkinson trignes is usually through.