What is ADHD? ADHD (attention deficit-hyperactivity disorder) affects both adults and school-aged children. Symptoms include restlessness, difficulty paying attention, and hyperactivity. The causes of ADHD are unknown, however factors such as diet, environment and genetics may contribute to symptoms.
The knee muscles control how the knee joint and patella move. There are two main groups of muscles, the quadriceps and the hamstrings, as well as a small muscle behind the knee (popliteus).
The quadriceps tendon attaches the quadriceps muscles to the patella. The patella is attached to the shinbone (tibia) by the patellar tendon. Working together, the quadriceps muscles, quadriceps tendon and patellar tendon straighten the knee. Quadriceps tendon tears can be either partial or complete.