<P> Some signs may have no meaning to the patient, and may even go unnoticed, but may be meaningful and significant to the healthcare provider in assisting diagnosis . </P> <P> Examples of signs include elevated blood pressure, a clubbing of the ends of fingers (which may be a sign of lung disease, or many other things), a staggering gait (human) and arcus senilis of the eyes . </P> <P> The term sign is not to be confused with the term indication, which in medicine denotes a valid reason for using some treatment . </P> <P> The art of interpreting clinical signs was originally called semiotics (a term now used for the study of sign communication in general) in English . This term, then written semeiotics (derived from the Greek adjective σημειωτικός: semeiotikos, "to do with signs"), was first used in English in 1670 by Henry Stubbes (1631--1676), to denote the branch of medical science relating to the interpretation of signs: </P>

What is the main sign of lung disease