Fig. 7

Transverse mid-sagittal dorsal image of the sagittal ridge of the third metacarpal bone. A thin mid-sagittal irregularly marginated hypoechoic defect is seen at the sagittal ridge (arrow), with irregular subchondral hyperechoic margins and heterogeneous hyperechoic material within the defect. Mild undulant thickening of the superficial articular cartilaginous margins Marker is to medial