ObjectiveTo measure L1-L5 lumbar isthmus thickness and to construct Chinese adult male lumbar (L1-L5) 3D model by Micro CT 3D reconstruction technique, in order to provide micro-anatomical data for clinical treatment of L1-L5 lumbar spondylolysis. MethodsDry, non-damaged specimens of L1-L5 lumbar isthmus from 60 Chinese adult males were randomly selected from September 2013 to January 2014. Micro CT scanning was carried out, followed by corresponding 3D model construction. The microscopic anatomical parameters such as superior, inferior, inner and outer edge thickness of left and right L1-L5 lumbar isthmus were measured. ResultsL1-L5 lumbar isthmus superior edge thickness was in the order of L1> L2> L3> L5> L4, with the variation ranging from (4.31±0.95) mm to (4.88±0.75) mm. L1-L5 lumbar isthmus inferior edge thickness was in the order of L1< L2< L3< L4< L5, gradually thickened with the variation ranging from (6.03±1.01) mm to (7.27±1.27) mm. L1-L5 lumbar isthmus inner edge thickness amplitude was not obvious, ranging from (6.33±1.21) mm to (6.57±1.27) mm. L1-L5 lumbar isthmus outer edge thickness was in the order of L1< L2< L3< L4< L5, gradually thickened with the variation ranging from (8.44±1.21) mm to (10.27±1.28) mm. ConclusionThere are certain rules within superior, inferior, inner and outer edge thickness of adult L1-L5 lumbar isthmus:the inferior and outer edge thickness of L1-L5 lumbar isthmus gradually becomes thicker, while superior edge gradually becomes thinner. From L1 to L5 lumbar isthmus, the outer edge of the lumbar isthmus is the thickest, followed by inner and inferior edge, and the upper edge is the thinnest.