How does the knee work?
The knee is the joint that connects the bones of the upper and lower leg. It is needed for pretty much any form of movement – such as running, cycling or swimming. The knee is the body’s largest joint, and it has a fairly complex structure. This structure makes it possible for us to bend and straighten our knees, and to turn them slightly inward or outward.
A healthy knee can be moved from 0 degrees (completely straight) to about 150 degrees (calf touching the back of your thigh). A bent knee can be turned inward (towards the other leg) by about 10 degrees, and outward by about 30 degrees. A number of bones, muscles, and ligaments come together in the knee joint.