손목 관절의 Measurements

1. Ulnar variance

1) Ulnar variance refers to the position of the cortical margin of the distal ulna relative to that of the distal radius. 

2) 60% of the population are ulnar neutral. 

3) If < 0 mm then negative ulnar variance, associated with keinbock disease

    If > 0 mm then positive ulnar variance, associated with ulnar abutment syndrome

2. Radial height

1) The distance between one line perpendicular to the long axis of the radius passing through the distal tip of the radial styloid. 

2) A second line intersects distal articular surface of ulnar head.

3. Radial inclination

1) The angle between one line connecting the radial styloid tip and the ulnar aspect of the distal radius and a second line perpendicular to the longitudinal axis of the radius. 

2) Loss of radial inclination will increase the load across the lunate.

4. Radiocarpal angle

1) Measured by first establishing reference lines. These are the radial centreline and a right-angle line. 

2) Formed between this right angle lien and a line drawn from the tip of the radial styloid to the tip of the ulnar styloid.