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.
When youâre experiencing back knee pain, the cause of the problem may be due to a condition known as a Bakerâs cyst. When the back knee pain is associated with a Bakerâs cyst, it isnât a cyst in the usual sense. Itâs a popliteal cyst. What this means is that fluid is present in the joint at the back of the knee.
Finding the Cause. 1  Location: Where on the knee the patient feels pain can offer some clues about what type of injury or condition is causing the pain. For instance, pain on the inside or medial side of the knee (the side closest to the other knee) can be caused by medial meniscus tears, MCL injuries, and arthritis.