HYPERMOBILITY OF JOINTS AS A SEX LINKED HEREDITARY CHARACTERISTIC

Abstract

This is a report of what might be termed a "double jointed" family, in which the abnormal mobility of the joints is present in all the male members and is absent in all the females. Other than an occasional brief description of a contortionist in some of the older medical journals, I have not found hypermobility of otherwise normal joints mentioned in the literature. The term hypermobility of joints suggests the question, What is the normal range of motion in the various joints? An answer to that question presents many difficulties and will not be attempted in this paper. It can be stated, however, that there may be considerable differences in the range of motion in the corresponding normal joints of different individuals, and that, as a rule, the joints of slender persons can be moved through wider arcs than can the corresponding joints of persons of the heavy type.