Ultrasound MCP joint showing cartilage and grayscale

This transverse ultrasound scan of the dorsal side of the second MCP joint shows the bone (hyperechoic curvilinear surface at bottom arrowhead) and cartilage (anechoic curvilinear surface between arrowheads) of the metacarpal head. The vertical bar at the far left border of the scan shows all grayscale intensities ranging from anechoic (black) at the bottom to hyperechoic (bright white) at the top.