Painful basal joint arthritis of the thumb. Part I: Anatomy, pathophysiology, and diagnosis.

Pathology at the base of the thumb can often be confusing. Numerous tendons, nerves, bones, and joints are all in close proximity and may cause pain and loss of function to the thumb. A systematic approach to this area, identifying abnormal anatomy or lesions of these structures, is presented along with the characteristic features of the examination of the pathologic basal joint. The importance of obtaining a careful medical history with regard to possible causes and symptoms is presented. Concurrent conditions, which are present in a large percentage of patients, are discussed. Radiographic views for diagnosis and staging will be demonstrated.