Unhappy triad posterior translation of the tibia on the femur. The classic O'Donoghue triad is characterized by an injury to three knee structures (in order): The anterior cruciate ligament is one of the four crucial ligaments in the knee. It originates from the lateral condyle of the femur and goes to the intercondyloid eminence of the tibia. Its function is to provide stability in the knee and minimize stress across the knee joint. It also restrains excessive forward movement in the leg and limits rotational movements in the knee. Injury An anterior cruciate ligament injury results from excess tension on the ligament.
Stifle joint stabilized by paired collateral ligaments which act to prevent abduction/adduction at the joint, as well as paired cruciate ligaments. The cranial cruciate ligament and the caudal cruciate ligament restrict cranial and caudal translation (respectively) of the tibia on the femur. The cranial cruciate also resists over-extension and inward rotation, and is the most commonly damaged stifle ligament in dogs. 'Cushioning' of the joint is provided by two C-shaped pieces of cartilage called menisci which sit between the medial and lateral condyles of the distal femur and the tibial plateau. The main biomechanical function of the menisci is probably to divide