Tendons are strong fibrous structures. A tendon is the end of the muscle (or group of muscles) that connect and anchor that muscle to bone and therefore move the bone. There are number of tendons in and around the knee but the 2 main tendons are the quadriceps and patellar tendons.
Tendons can cause pain by becoming inflamed (tendonitis) which can be treated in a variety of ways. Tendons can also tear and may require repair.