Transverse section, showing the relations of the capsule of the kidney.
Image of a human back
Costovertebral angle tenderness (CVAT), also known as Murphy's punch sign or the Pasternacki's Sign (Latin: succusio renalis), is a medical test in which pain is elicited by percussion of the area of the back overlying the kidney (the costovertebral angle, an angle made by the vertebral column and the costal margin). The test is positive in people with an infection around the kidney (perinephric abscess), pyelonephritis or renal stone. Because the kidney lies directly below this area, known as the costovertebral angle, tapping disturbs the inflamed tissue, causing pain.
This medical test was first described by the American surgeonJohn Benjamin Murphy in 1884, but in Eastern Europe and former Soviet Influenced Regions, it is often called Pasternacki's Sign after the Belorussian Internist, Fiodor Ignatjevich Pasternacki (1845–1902) who described it during his rounds in a Regional Hospital in Minsk in 1888.