Fig. 6

Longitudinal mid-sagittal dorsal image of the metacarpophalangeal joint. The third metacarpal bone is to the left and the proximal phalanx to the right of the image. A thin well-defined hypoechoic region superficial to the hyperechoic subchondral bone represents the normal cartilage of the distal condyle of the third metacarpal bone (MC3) (arrow). Marker is to proximal