The document discusses various ligament injuries in the knee. There are four main ligaments in the knee - the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), lateral collateral ligament (LCL), and medial collateral ligament (MCL). Injuries to these ligaments can occur during sports or accidents and cause symptoms like pain, swelling, popping sensations, and instability in the knee. Treatment options include rest, compression, elevation, pain relievers, and in some cases reconstructive knee surgery.