**Question:** All of the following are true about ACL. Except-

A. Anterior Cruciate Ligament (ACL) is a crucial structure in maintaining knee joint stability.
B. ACL is responsible for restricting anterior tibial translation.
C. ACL can be injured due to shear forces during quick changes in direction or landing from a jump.
D. ACL is solely responsible for flexion and extension movements of the knee joint.

**Correct Answer:** **D. ACL is solely responsible for flexion and extension movements of the knee joint.**

**Core Concept:** The Anterior Cruciate Ligament (ACL) is an important structure within the knee joint that plays a crucial role in maintaining joint stability and preventing excessive anterior tibial translation. The ACL is primarily responsible for restricting anterior movement between the tibia and femur, preventing abnormal sliding of the tibia forward over the femur.

**Why the Correct Answer is Right:** ACL is primarily responsible for preventing excessive anterior tibial translation, ensuring stability of the knee joint, and reducing the risk of dislocation. It plays a significant role in maintaining joint balance and preventing excessive movement between the tibia and femur.

**Why Each Wrong Option is Incorrect:**

A. Although the ACL plays a vital role in maintaining knee joint stability, it is not responsible for flexion and extension movements alone. The ACL, together with the other knee ligaments (Posterior Cruciate Ligament, MCL, LCL), contributes to the overall stability of the knee joint and helps regulate the range of motion.

B. Similar to option A, ACL is involved in maintaining stability and regulating the range of motion, not solely responsible for flexion and extension movements. The knee joint is a hinge joint that relies on various structures, including ligaments, muscles, and tendons, for its function.

C. This statement is true, as ACL injury is a common phenomenon, especially during sports activities involving sudden changes in direction or landing from a jump. ACL injury can lead to instability and decreased knee joint function, requiring surgical intervention in severe cases.

E. ACL plays a significant role in maintaining knee joint stability and ensuring appropriate joint movement, but it is not solely responsible for flexion and extension movements. ACL, along with other knee structures, contributes to the overall stability of the joint and regulates its movement within a specific range.

**Clinical Pearl:** Understanding the role of ACL and other knee ligaments, muscles, and tendons is essential for recognizing potential injuries and managing them appropriately. Knowledge of the joint's anatomy and biomechanics will help clinicians diagnose, treat, and prevent ACL injuries, ensuring optimal patient care and outcomes.