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).
What is behind knee swelling? A swollen area that can be felt behind the knee can be caused by several different conditions. A Bakerâs cyst is a collection of synovial fluid (fluid that is present within joint spaces) that bulges out through the back of the knee joint and can be felt in the back of the knee as a lump or enlarged area.