Left, Under regular light microscopy, cholesterol crystals are clearly visible in synovial fluid. These crystals are much larger than other crystals found in synovial fluid. Cholesterol crystals are present at times in chronic inflammatory effusions, in this case in the synovial fluid of a patient with rheumatoid arthritis. Their clinical significance is unknown, although experiments in animals suggest that these crystals cause mild inflammation. Right, Synovial fluid is viewed under polarized light microscopy in which there is contamination with starch that was shed from a glove. Starch gives the appearance of Maltese crosses under polarized light. Self Learning Series. Philadelphia, Pa: American College of Physicians; 1978.