In a previous communication we 1 reported an interesting example of a neuro-arthropathy of peripheral nerve origin. Since its publication, a fortuitous circumstance has permitted us to place on record another instance of this little understood joint anomaly. Before proceeding with a detailed description of the two cases observed and their subsequent course, it will be necessary, for a clearer understanding of the subject of neuro-arthropathies in general, to quote in part from our former publication.The association of bony changes\p=m-\limitedprincipally to joint structures\p=m-\withgrave disease of the central nervous system has been observed for a great number of years. The recognition of such structural osseous anomalies occurring in the course of tabes and syringomyelia was given impetus by Charcot, who was the first to describe them accurately. Thus the term Charcot joint found universal acceptance in the literature and was readily interpreted as a destructive arthritic process dependent on and secondary to involvement in a dis¬ ease process of certain fiber tracts in spinal cord parenchyma. As tabes and syringomyelia were apparently the only affec¬ tions that developed such arthropathies fairly consistently, it was readily assumed that they were peculiar to these diseases only and that such profound joint changes could develop on no other basis.The advent of the roentgen ray served further to emphasize the existence of these arthropathies, since the diagnosis could be made quite early before they are demonstrable clinically and before grave destructive changes take place. The assump¬ tion that they existed only in association with such diseases of the central neural axis as tabes and syringomyelia seemed justifiable, since these arthropathies were never observed in any other condition. The routine use of the roentgen ray in bone and joint conditions, however, revealed the fact that affections other than those heretofore mentioned were capable of setting up changes in joints comparable to the classic arthropathy of Charcot, and it is of these in particular that we wish to speak.That this possible widespread misconception of neuroarthropathies may have great potentialities for harm makes it imperative that its existence be recognized outside the domain of the tabetic or syringomyelitic patient. The detec¬ tion of a neuro-arthropathy presents no special difficulties and need not be dwelt on. Confusion will arise, however, when such an instance presents itself in the absence of the accepted orthodox diseases that create neuro-arthropathies. This state of affairs occurred in the patient studied by us, and the misin¬ terpretation of the negative neurologic and serologie findings led his previous medical advisers to perform an unnecessary joint operation for suspected malignancy.The foregoing quotations should serve in the main to foster the conception that we have ventured to formulate, that a neuro-arthropathy may be wholly the product of peripheral nerve disease or injury. The theoretical considerations of the ...