Anatomy
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Bones. Three bones meet to form your knee joint: your thighbone (femur), shinbone (tibia), and kneecap (patella).
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Articular cartilage. The ends of the femur and tibia, and the back of the patella are covered with articular cartilage. This slippery substance helps your knee bones glide smoothly across each other as you bend or straighten your leg.
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Meniscus. Two wedge-shaped pieces of meniscal cartilage act as "shock absorbers" between your femur and tibia. Different from articular cartilage, the meniscus is tough and rubbery to help cushion and stabilize the joint. When people talk about torn cartilage in the knee, they are usually referring to torn meniscus.
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Ligaments. Bones are connected to other bones by ligaments. The four main ligaments in your knee act like strong ropes to hold the bones together and keep your knee stable.
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Collateral Ligaments. These are found on the sides of your knee. The medial collateral ligament is on the inside of your knee, and the lateral collateral ligament is on the outside. They control the sideways motion of your knee and brace it against unusual movement.
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Cruciate ligaments. These are found inside your knee joint. They cross each other to form an "X" with the anterior cruciate ligament in front and the posterior cruciate ligament in back. The cruciate ligaments control the back and forth motion of your knee.
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Tendons. Muscles are connected to bones by tendons. The quadriceps tendon connects the muscles in the front of your thigh to your patella. Stretching from your patella to your shinbone is the patellar tendon.
Your knee is made up of many important structures, any of which can be injured. The most common knee injuries include fractures around the knee, dislocation, and sprains and tears of soft tissues, like ligaments. In many cases, injuries involve more than one structure in the knee.
Pain and swelling are the most common signs of knee injury. In addition, your knee may catch or lock up. Many knee injuries cause instability — the feeling that your knee is giving way.
Conditions
Exercise Program
Protocols
Setup Begin sitting upright on the floor with one leg laying straight and your other knee bent. Movement Straighten your leg, pushing your knee toward the floor, and hold.
Movement Cross your uninvolved leg over your other ankle, and use that leg to gently slide your foot toward your buttocks as far as is comfortable. Then slide your foot back out and repeat.
Setup Begin in a standing upright position, with your feet hip width apart. Movement Bend your knees and hips into a mini squat position, then straighten your legs and repeat.
Setup Begin sitting upright on the floor with one leg laying straight and your other knee bent. Movement Straighten your leg, pushing your knee toward the floor, and hold.
Knee
In 2010, there were roughly 10.4 million patient visits to doctors' offices because of common knee injuries such as fractures, dislocations, sprains, and ligament tears. Knee injury is one of the most common reasons people see their doctors.
Your knee is a complex joint with many components, making it vulnerable to a variety of injuries. Many knee injuries can be successfully treated with simple measures, such as bracing and rehabilitation exercises. Other injuries may require surgery to correct.