Microvilli (singular: microvillus) are microscopic cellular membrane protrusions that increase the surface area of cells and minimize any increase in volume, and are involved in a wide variety of functions, including absorption, secretion, cellular adhesion, and mechanotransduction. 1 Locations.
Activities such as bending the knee, kicking or running can worsen the pain. The calf muscle, or gastrocnemius, aids in propelling you forward while walking or running. A strain at the upper end of the gastrocnemius causes pain in the back of the knee that worsens with knee bending or rising to your tiptoes. The popliteus muscle helps stabilize the knee joint during movement. Injury to this muscle can be challenging to diagnose.
Symptoms may include; visible swelling or protrusion on the back of the knee (which can be painful or painless), constant and prolonged knee pain, and tightness at the back of the knee or simply a feeling of tenderness at the back of the knee.