Correlations of morphological observation and measurement of the chiasmatic cistern with the protection of optic nerves and optic chiasm

doi:10.3321/j.issn:1673-8225.2004.28.018

Abstract：BACKGROUND:The accurate data about the microstructure of chiasmatic cistern are still not available. OBJECTIVE:To explore the boundary,microstructure,characteristics and clinical significance of chiasmatic cistern. DESIGN:Sample survey. SETTING and PARTICIPANTS:The study was carried out at the Operation Microsscope Room of Medical College of Xinning College.Chiasmatic cistern sample was collected from 16 males and 4 females with their ages ranged from 30 to 60 years old. INTERVENTIONS:Frontal lobe was eliminated with operation microscope,while the soft meninges under frontal lobe,arachnoid and sphenoid saddle surrounding configuration were kept for investigating the boundary of chiasmatic cistern and the anatomical relationship of its microstructures. MAIN OUTCOME MEASURES:The boundary of chiasmatic cistern,morphometry and anatomical relationship of its microstructures,characteristics and its relative value. RESULTS:Chiasmatic cistern was surrounded by arachnoid extended from between optical nerves to optic chiasm and sphenoid saddle.In the chiasmatic cistern,bilateral length of encephalic segment of optic nerve was( 9.89± 2.63) mm with thickness of( 2.96± 0.82) mm.The longitudinal diameter of optic chiasm was( 10.87± 1.63) mm with transversal diameter of( 13.38± 1.52) mm and thickness of( 4.68± 0.72) mm.Optic chiasm was found normal in 10 patients(50% ),prepositive in 7 patients(35% ),and postpositive in 3 patients(15% ).Length of pituitary handle was( 5.98± 2.7) mm with longitudinal diameter of 1.59± 0.42) mm and transversal diameter of( 1.96± 0.44) mm.The aperture of fibrin net was smaller than 0.06 mm. CONCLUSION:Optic chiasm is the center of chiasmatic cistern,which is surrounded by anterior optical nerves, posterior pituitary handle,and inferior pituitary with sphenoid saddle between them.The microstructures of chiasmatic cistern is connected with each other by fibrin net and vessels tangled on it, making chiasmatic cistern a complex structure.Therefore,anatomical study of optical nerves,optical chiasm,and vessels in chiasmatic cistern should be carefully protected during clinical operations at sphenoid saddle.