ANATOMY

The normal scapholunate angle on a lateral x-ray is 30–60°
The radiolunate angle is between 15° of lunate flexion and 20° of lunate extension
The radiolunate and lunocapitate articulations lie along the same axis

There are 3 carpal arcs

      • Arc of proximal articulations of the proximal row
      • Arc of distal articulations of the proximal row
      • Arc of proximal articulations of the distal row

Carpal height is measured between the base of the third metacarpal and the subchondral region of the distal radius.
Expressed as a ratio to 3rd metacarpal length and normally 0.54
The modified carpal ratio is carpal height / capitate length and is 1.57

Ulnar variance should be measured with the wrist in neutral position and elbow at shoulder height.
Pronation increases the apparent length of the ulna and supination decreases it
A horizontal line is drawn perpendicular to the axis of the radius from the distal ulnar border of the radius.
Ulnar variance is the distance between this line and the ulnar distal rim.
A stress series includes images in ulnar and radial deviation and grip PA and lateral