Ulnar styloid impingement syndrome.
The tip of an excessively long ulnar styloid can impinge upon the triangular fibrocartilage complex (TFCC) against the triquetrum. The subtleties in biomechanics of the wrist joint and their role in the production of the symptoms are presented as five cases from a retrospective study. The relationship of the symptoms to the patients' job activities is also discussed. The embryological and anatomical studies show that the tip of the ulnar styloid is covered by the TFCC. Therefore, the term "ulnar styloid impingement syndrome" is adopted for the entity in cases in which the TFCC has remained intact.