Fig. 2
From: Quantitative assessment of distal radioulnar joint stability with pressure-monitor ultrasonography
An example of an ultrasound measurement. a Initial position. A1: distance between the dorsal surfaces of the ulnar and the radius at the initial position. b Final position after compression. A2: distance between the dorsal surfaces of the ulnar and the radius at the final position after the compression. Arrow shows pressure to the ulna. A1–A2 were defined as the changes of radioulnar distance