Definition Cyanosis refers to bluish(带蓝色的 带青色的) color of the skin and mucous membranes resulting from an increased quantity of reduced hemoglobin(亚铁血 红蛋白;还原血红蛋白),orof hemoglobin derivatives, in the small blood vessels of those areas. It is usually most marked in the lips, nail beds(甲床),ears, and malar (颧骨的;颊的) eminences