scapholunate angle

The SL angle,

which is an indicator of dorsal intercalated segment instability deformity (DISI). The SL angle goes between:[1] A line through the long axis of the scaphoid bone. A line perpendicular to the distal articular surface of the lunate bone. ↑ Page 75 in: Leiv M. Hove, Tommy Lindau, Per Hølmer (2014) Distal Radius Fractures: Current Concepts, Springer ISBN: 9783642546044.

Scapholunate

advanced collapse: a pictorial review. Normal alignment versus rotary subluxation of the scaphoid. a Lateral radiograph of the wrist showing normal alignment and rotation of the lunate (black outline) and scaphoid (white outline), with a normal scapholunate angle of 45° (black lines). b Lateral radiograph of the wrist of a different patient depicting rotary subluxation of the scaphoid. There is abnormal rotation of the scaphoid (white outline) where the proximal pole of the scaphoid has moved dorsally and there is volar tilt, causing an abnormal scapholunate angle of 70° (black lines). Note is made that the normal lunate angulation is maintained

Scapholunate

advanced collapse: a pictorial review. Rotary subluxation of the scaphoid. Imaging findings in three different patients. a Posteroanterior radiograph of the wrist shows a widened scapholunate distance (black arrow) and foreshortening of the scaphoid with a “signet ring” sign (white arrowheads). b Lateral radiograph (left image) and sagittal CT reformat image (right image) of the wrist demonstrating an increased scapholunate angle of 70° on radiograph (black lines) and increased radioscaphoid angle of 65° on CT (white lines). c Lateral wrist radiograph showing subluxation of the scaphoid onto the dorsal rim of the radius (black arrowheads)

Scapholunate

angle • Normal wrist alignment, dorsal and volar intercalated segmental instability (illustration) - Ganzer Fall bei Radiopaedia