Ultrasonography of the 2nd proximal interphalageal joint. The joint is visualized in sagittal (a,c) and axial (b,d) scans. In a gray-scale image (a), proximal and distal osteophytes are visible (arrows). Gray-scale synovitis is visible in both sagittal (a) and axial (b) planes (arrowheads). Power Doppler signal is visible in (c) and (d).
Haugen and Bøyesen Arthritis Research & Therapy 2011 13:248 doi:10.1186/ar3509