the world > health and disease > ill health > a disease > diseases of tissue > disorders of joints > [noun] > bursitis > of knee (3)
inflammation of the bursa over the kneecap (prepatellar bursa), typically induced by kneeling on hard floors.
water on the knee: effusion of fluid in the knee joint.
inflammation of the prepatellar bursa; = housemaid's knee at housemaid, n. compounds 2.