<prompt> Anterior cruciate ligaments prevent:Anterior dislocation of ulnaPosterior dislocation of ulnaAnterior Dislocation of tibiaPosterior dislocation of tibia  <response>: Ans. c Anterior Dislocation of tibiaRef: Maheshwari 5th ed. 148-149 The anterior cruciate ligament ACL stretches from the lateral condyle of femur to the anterior intercondylar area. The ACL is critically important because it prevents the tibia from being pushed too far anterior relative to the femur. It is often torn during twisting or bending of the knee. ACL is considered as the major stabilizer of the knee. Therefore, ACL Tears are the most common knee injuries. If there is ACL tear, reconstruction is most commonly done by autograft, meaning the tissue used for the repair is from the patients body. The two most common sources for tissue are the patellar tendon and hamstrings tendon The posterior cruciate ligament PCL stretches from medial condyle of femur to the posterior intercondylar area. This ligament prevents posterior displacement of the tibia relative to the femur. 