Swelling of the knee.
D001170:Arthritis, Infectious / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D007223:Infant; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D011859:Radiography; D013203:Staphylococcal Infections / Q000000981:diagnostic imaging*