Ulnar Variance

 ulnar variance xray
  1. Ulnar Variance: determined on neutral rotation P/A view. Measured by drawing a transverse line at the level of the lunate fossa and a second transverse line at the level of the ulnar head, and determining the distance between the two lines. Positive ulnar variance increases with power grip and pronation. Consider pronated grip view. (Tomaino MM, J Hand Surg 2000;25Am:352). Normal = neutral (articular surface of distal ulna and radius equal). Postive (ulna longer) associated with ulnocarpal impaction, lunotriquetral ligament injurie and TFCC tears. Negative (ulna shorter) associated with carpal instability, Keinbock's disease
  2. Ulnocarpal Impaction Syndrome is indicated by cystic / sclerotic lesions in the lunate and proximal medial ulna best seen on the P/A view