context: Ligaments are bands of tough elastic tissue around your joints. They connect bone to bone, give your joints support, and limit their movement. You have ligaments around your knees, ankles, elbows, shoulders, and other joints. Stretching or tearing them can make your joints unstable. The most common ligament injuries come from playing sports. You can also injure them in accidents or from general wear and tear. Treatment for these injuries can include: Rest Physical therapy Surgery In the first 72 hours, you may need to: Ice the injured joint regularly. Use a brace or bandage. Elevate the injury. There are four major ones connecting your thighbone (femur) and shinbone (tibia): Anterior cruciate ligament ( ACL) Posterior cruciate ligament ( PCL) Medial cruciate ligament ( MCL) Lateral collateral ligament ( LCL) The anterior and posterior cruciate ligaments are in the center of your knee. The ACL is toward the front of your knee. It controls forward movement and rotation of your shinbone. The PCL is toward the back of your knee and controls backward movement of your shinbone. The MCL is on the inside of your knee and gives that area stability. The LCL is on the outside of your knee and keeps the area around it stable. The most common knee ligament injury is to the anterior cruciate ligament. If your feet plant in one direction and your knee is twists in another, it can strain or tear your ACL. Football, skiing, and basketball are all sports with a higher risk of ACL injuries. A PCL injury usually happens from a sudden direct impact, like a football tackle or a car accident. MCL tears or strains usually happen because something hits the outside of your knee. The two main ligaments around the elbow are the ulnar collateral ligament ( UCL) and the radial collateral ligament. Both connect the bone in your upper arm (called the humerus) to the bone on the pinky side of your forearm (you may know it as the ulna). The radial collateral ligament connects the humerus to the outer forearm bone called the radius but also extends to the ulna providing additional support. The ulnar collateral ligament runs along the inside of your elbow. The lateral collateral ligament goes along the outside. A third ligament, the annular ligament, circles the top of the other bone in your forearm (called the radius). It holds it against the ulna. Throwing something over and over again can stretch or tear your UCL. Baseball pitchers can damage it over time until it tears. It can happen to javelin throwers and other athletes, too. You can also rupture your UCL by falling on your arm when it's outstretched. Ligaments in the shoulder connect your humerus to your shoulder blade (also called the scapula). They also connect the clavicle, or collarbone, to the top of your shoulder blade. When these get stretched, your shoulder becomes unstable. This happens a lot to young people and athletes who put strain on their shoulders, like pitchers in baseball. You can also sprain or tear your shoulder ligament when you use your arm to brace yourself when you fall. There are several ligaments around your ankle. The three main ones on the outside part of your ankle are the anterior talofibular ligament, the posterior talofibular ligament, and the calcaneofibular ligament. All three begin on your fibula. That's the thin bone outside your shinbone. It's also the bone you feel on the outside of your ankle. The calcaneofibular ligament connects the fibula to your heel bone. The anterior talofibular and posterior talofibular ligaments connect the talus (the bone between your heel and shinbone) to the fibula on the outside of the ankle. The ligament complex on the inside part of the ankle is called the deltoid ligament. It connects the tibia to the same bones as the lateral ligaments but on the inside of your foot in addition to the navicular bone for added support. When you sprain your ankle, you're tearing one of these ligaments. The most common sprain happens when your foot rolls under your ankle or leg. This usually happens playing sports, especially jumping sports like basketball. When you sprain your ankle, you're usually hurting one of these ligaments. A third ligament, the posterior talofibular ligament, runs along the back of your ankle. Injuries to this ligament aren't as common.