A major cause of less than ideal results following intraarticular anterior cruciate ligament (ACL) reconstruction has been imprecise nonanatomic tunnel position for graft placement either in the femur, the tibia, or both. Lack of defined constant reference landmarks for reproducible tunnel placement has contributed to this problem on both sides of the joint. The purpose of this study was to define constant anatomic intraarticular and extraarticular landmarks that can be used as definitive reference points to reproducibly create a tibial tunnel for ACL reconstruction that (1) results in an impingement-free graft in full extension; (2) positions the tibial tunnel such that the sagittal tunnel-plateau angle is parallel with the sagittal intercondylar roof-plateau angle in full extension to minimize shear seen by the graft at the tibial tunnel inlet. Preoperative full extension and 90degrees flexion lateral radiographs were obtained. Preoperative measurements of the tibial tunnel-tibial shaft angle and distance from inferior pole of patella to entry point of tibial tunnel were useful tool for impingement free, Blumensaats line paralleling ACL reconstruction with autogenous bone patella tendon bone graft. The average tibial tunnel-tibial shaft angle was 34±4.59degrees (male), 33.5±3.37degrees (female). The mean distance between patella inferior pole and tibial tunnel entry point was 6.62±0.61cm (male), 6.21±0.89cm (female). This study sought to define constant anatomic landmarks extraarticularly as well as intraarticularly that can be used to reliably create an ideal tibial tunnel for ACL reconstruction.