Sonography of the normal scapholunate ligament and scapholunate joint space

Purpose. The aims of this study were to assess the visibility of the normal scapholunate ligament on sonography and to establish the normal scapholuna te joint space width in the neutral position and radial and ulnar deviation . Methods. Two hundred normal wrists in 100 subjects (55 men and 45 women; me an age, 40 years; range, 19-83 years) were examined with high-resolution so nography (5-12-MHz linear-array transducer). The visibility and thickness o f the scapholunate ligament were recorded. The width of the scapholunate jo int space, or interval, was measured in the neutral position and radial and ulnar deviation. The width of the distal radius was recorded as a comparat ive standard for the patients' body habitus. Results. The dorsal scapholunate ligament was completely (100%) visible in 95 wrists (48%), partially (greater than or equal to 50%) visible in 60 (30 %), barely (< 50%) visible in 15 (8%), acid not visible in 30 (15%). The vo lar scapholunate ligament was completely visible in 13 wrists (7%), partial ly visible in 17 (9%), barely visible in 15 (8%), and not visible in 151 (7 6%). The proximal component of the ligament was not visible in any subject. Measurement of the scapholunate interval was limited by the lack of identi fiable anatomic marks for reference. The mean width of the dorsal scapholun ate interval was 4.2 mm (range, 2.3-6.3 mm) in the neutral position. The in terval did not differ more than 2.5 mm between the left and right wrists. N o predictable change in width on ulnar or radial deviation was evident. The mean scapholunate intervals and mean distal radial width were significantl y wider in men than in women and on the right side than on the left side. Conclusions. The dorsal scapholunate ligament is completely or partially vi sible in 78% of normal wrists. Its detection following injury may help to e xclude the possibility of scapholunate dissociation. There is a quite wide variation in scapholunate interval widths on sonography and an unpredictabl e response with stress testing. The absence of a visible scapholunate ligam ent on sonography does not indicate injury. (C) 2001 John Wiley & Sons, Inc .