Atlas of MSK Measurements
Method of Perpendiculars - draw line along long axis of the radius (light line). draw line perpendicular to this, through the ulnar corner of the radius (dark line).
if < 0 mm then negative ulnar variance, associated with keinbock
if > 0 mm then positive ulnar variance, associated with ulnar abutment syndrome
wrist ( RID2177 )
how to draw the ulnar variance