Kidney punch or CVA Tenderness is elicited when gently tapping the area of the back overlying the kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

producing pain in people with an infection around the kidney (perinephric abscess) or pyelonephritis

Pyelonephritis

Pyelonephritis is an ascending urinary tract infection that has reached the pyelum or pelvis of the kidney. It is a form of nephritis that is also referred to as pyelitis...

 or renal stone. Since 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 surgeon

Surgeon

In medicine, a surgeon is a specialist in surgery. Surgery is a broad category of invasive medical treatment that involves the cutting of a body, whether human or animal, for a specific reason such as the removal of diseased tissue or to repair a tear or breakage...

 John Benjamin Murphy

John Benjamin Murphy

John Benjamin Murphy, born John Murphy , was an American physician and abdominal surgeon noted for advocating early surgical intervention in appendicitis appendectomy, and several eponyms: Murphy’s button, Murphy drip, Murphy’s punch, Murphy’s test, and Murphy-Lane bone skid...

.