Figure 12.14 Anterior view of the right knee showing the medial and lateral collateral ligaments, the anterior and posterior cruciate ligaments, the medial and lateral menisci, and the transverse ligament. (From Levangie P, Norkin C. Joint Structure and Function: A Comprehensive Analysis, 5th ed. Philadelphia, PA: F. A. Davis Company, 2011: p. 400, with permission.)
Stretched ACL
Patellar tendon
Figure 12.16 Combined excessive genu valgus and medial rotation and adduction of the femur increases tension in the ACL ligament.
Quadriceps Patellar tendon Taut ACL
Posterior capsule
Hamstrings
Extension
Figure 12.15 As the quadriceps extends the knee, it slides the tibia anteriorly in relation to the femur. The anterior cruciate ligament, posterior joint capsule, and hamstring muscles check this anterior movement.