a recognition that genres are situated within discourse communities, wherein the beliefs and naming practices of members have relevance an emphasis on communicative purpose and social action an interest in generic structure (and its rationale)
Because of the potential implication of circulation disorders, darkened skin around the ankles that is not immediately explainable by simple environmental factors should be promptly called to the attention of a medical doctor for appropriate diagnosis and treatment.
However, the fact that they're not alive means that they will have a darker, dead appearance than healthy cells. When the dead skin cells build up on your elbows and knees, exposure to sunlight will cause them to darken, giving you those dark spots. Dirt -- Yes, it may be hard to hear it, but dirt can be a major cause of the dark spots on your elbows and knees.