ACL, MCL, LCL and PCL
Your bones are connected by ligaments. The bones in the knee include the thigh bone (femur), the lower leg bone (tibia) and the kneecap (patella). In between the thigh bone and the leg bone is another important structure called the meniscus. The medial and lateral menisci are made of soft cartilage that cushions the knee and helps it absorb shock during motion. There are four major ligaments in the knee to help with knee stability, or making sure that your knee doesn’t “give out.”
Two of these ligaments are called the medial and lateral collateral ligaments. They are located on the inner and outer sides of the knee. The other two ligaments are found inside the knee joint and are called the anterior and posterior cruciate ligaments. They form an “X” in the middle of the knee, with the ACL located in front. (en Español)
Source and for additional information: American Academy of Orthopaedic Surgeons (AAOS)
Mas informacion sobre lesiones del ligamento cruzado anterior: AAOS en Español
Anterior Cruciate Ligament (ACL)
One of the most common knee injuries is an anterior cruciate ligament sprain or tear. This ligament functions to prevent the tibia from sliding out in front of the femur as well as providing stability with rotation. About half of all injuries to the anterior cruciate ligament occur along with damage to other structures in the knee, such as articular cartilage, meniscus, or other ligaments.