Egypt's second faith is Coptic Christianity. Copts are heirs of an ancient Christian rite. Coptic Christianity was the predominant religion in Egypt until the 10th century when a lot of Christians diverted to Islam. Christianity itself was brought in Egypt by St. Mark in the middle of the first century AD.
Other possible causes of swelling behind the knee include abscesses (infections); tumors of the skin, soft tissue, or bones; bleeding; deep venous thrombosis (blood clot in the deep veins of the legs); or deformity of the joint after a fracture of any of the bones of your knee joint.
A Baker cyst is swelling caused by fluid from the knee joint protruding to the back of the knee. Baker cysts are common and can be caused by virtually any cause of joint swelling (arthritis). A Baker cyst may not cause symptoms or be associated with knee pain and/or tightness behind the knee, especially when the knee is extended or fully flexed. Baker cysts can rupture and become complicated by spread of fluid down the leg between the muscles of the calf (dissection).