An ACL injury is the tearing of the “anterior cruciate ligament” (ACL) — one of the major ligaments in your knee. ACL injuries most commonly occur during sports that involve sudden stops, jumping or changes in direction — such as basketball, soccer, football, tennis, downhill skiing, volleyball and gymnastics.
Many people hear or feel a “pop” in the knee when an ACL injury occurs. Your knee may swell, feel unstable and become too painful to bear weight.
This 3D animation by Elara illustrates what it looks like when that injury happens, the forces behind it, and the anatomy of the injury.