The anterior cruciate ligament(ACL) is, perhaps, the most intriguing component of the knee joint. Initially referred to crucial ligament because of the cruciate or crossed arrangement or the anterior and posterior ligaments within the knee. the irony or the ACL being crucial to the well-being or the joint has only recently appreciated. The anterior cruciate ligament of human knee joint is a complex structure and its orientation, construct and biology arc directly related to the knee function as a constraint of knee joint motion. In addition to its functional role as a static stabilizer or the knee. the ACL has a unique neurovascular system. The vascular anatomy of the ACL plays a crucial role in the repair and reconstruction of the ligament, and the neuroreceptors found in its substance suggest a possible proprioceptive role for the ligament. The structural complexity of the ACL allows the ligament to function through the normal range of motion as a static stabilizer or the knee. hut it also makes the exact duplication of this structure very difficult. A comprehensive knowledge or the anatomy of the ACL can provide the orthopedic surgeon with a blueprint for the idealized repair and reconstruction of this most complex structure.