The patellar tendon attaches the bottom of the knee cap (patella) to the top of the shin bone (tibia). It is actually a ligament that connects two bones, the patella and the tibia.
The patella is attached to the quadriceps muscles by the quadriceps tendon. Working together, the quadriceps muscles, quadriceps tendon and patellar tendon straighten the knee and leg.
Small tears of the tendon can make it difficult to walk, participate in sports and activities of daily living. A large tear of the patellar tendon is a disabling injury and it usually requires surgery and physical therapy to regain full knee function.