What is the meaning of the term "normal" as applied to the human body? The results of physical examinations and laboratory tests are often recorded with the word "normal" jotted down with an easy assumption of accuracy entirely unjustified by the facts. In a discussion of this subject Ryle1 says that "normal" is commonly considered as synonymous with "healthy"; but that label too needs better definition.
Probably most physicians simply mean by "normal" that an obviously demonstrable pathologic lesion has not been found. Yet, as Ryle points out, even this is questionable. Palpable epitrochlear glands, for example, which may be as large as a cherry stone, are demonstrable in about 40 per cent of adult men, unrelated to the presence of syphilis or other generalized disease of the lymph nodes. To say that the presence of palpable epitrochlear glands, therefore, is or is not normal raises an interesting question.
WHAT IS "NORMAL"?. JAMA. 1947;133(14):1011. doi:10.1001/jama.1947.02880140041014