The unique talent of a clinician is his ability to examine a sick person, and to draw conclusions from the clinical observations. Clinicians acquire their skill at physical diagnosis in much the same way that they learn a foreign language. They study the basic principles of vocabulary, grammar, and style, and they learn to "think" in that language by augmenting their command of it in practical application. Once a substantial command is acquired, however, most clinicians assume that the basic thought principles will remain constant.
Like the vocabulary of a language, the terms used in history-taking and physical examination evolve slowly. New terms, such as asterixis and retinal microaneurysms, appear; semantic inadequacies, such as valvular insufficiency, are replaced by regurgitation. The "grammar" (or application) of the terms gives old words new meanings: the pain of angina pectoris, now recognized in occasional cases of pulmonary hypertension, is no longer pathognomonic of