Murphy's punch sign test, which is conducted for testing costovertebral angle tenderness, was first described by an American surgeon named John Benjamin Murphy.
The human rib cage comprises twelve pairs of ribs, twelve thoracic vertebrae, sternum, and costal cartilages. Only the first seven pairs (true ribs) attach directly to the sternum through the costal cartilage. The next three pairs (false ribs) are connected to the cartilage of the seventh pair. The last two pairs (floating ribs) are only attached to the vertebrae. Each of the twelve pairs is connected to the thoracic vertebra in the spine.

The term 'costovertebral angle' refers to the acute angle that is formed by the vertebral column and the twelfth rib on either side of the back. Murphy's kidney punch, which is also referred to as Murphy's punch sign, is a test involving percussion of the twelfth rib. This test is conducted to test for costovertebral angle tenderness (CVAT). If the patient experiences pain and/or tenderness, other diagnostic tests might be conducted to rule out certain medical conditions.

Contributing Factors for Costovertebral Angle Tenderness

More often than not, Murphy's kidney punch test is conducted to rule out renal involvement. Often associated with renal disease, CVA tenderness is mostly unilateral, and is felt around the affected kidney. However, it could be bilateral in some cases. The area in question overlies the kidneys. If one of the kidneys is affected by an infection, the percussion of this area is likely to disturb the inflamed renal tissue, thereby causing pain. In such cases, the likelihood of renal involvement is high, especially if the patient is also experiencing urinary symptoms. CVA tenderness is most likely to be experienced by individuals affected by the following conditions:

Kidney Stones/Urinary Stones

The kidneys perform the vital function of filtering the blood and collecting urine, which then flows into the ureter and the bladder. At times, certain minerals present in the urine might crystallize to form stone-like deposits. These deposits mostly form due to the crystallization of minerals and salts such as calcium, oxalate, uric acid, etc. When the stones are small, these might pass out of the body via urine. Large stones that remain lodged in the kidney can cause pain. The formation of stone-like deposits in the kidney is medically referred to as nephrolithiasis. This condition can also make one susceptible to kidney infections. Stone-like deposits could also form in other parts of the urinary tract. The presence of stones in the ureter and the bladder are medically referred to as ureterolithiasis and cystolithiasis, respectively. Flank pain is one of the characteristic signs of kidney stones. The symptoms that are usually felt by the affected individual include:

Flank pain that radiates to the groin
Abdominal pain
Distended abdomen
Difficulty in passing urine
Painful urination
Frequent urge to urinate
Blood in the urine

If an individual has been experiencing such symptoms along with CVA tenderness, diagnostic tests such as renal ultrasonography or computed tomography might be conducted to check for kidney stones.


Commonly referred to as a kidney infection, pyelonephritis could be caused due to a wide range of reasons. This is a type of urinary tract infection that could affect one or both kidneys. This could be caused due to bacteria or viruses. More often than not, a bacterium called Escherichia coli is the causal agent for a bacterial infection. The infection usually occurs when the disease-causing agent moves from the bladder into the kidneys. This infection could also be caused due to Vesicoureteral reflux (VUR), which is a condition that is characterized by the backflow of urine due to a faulty valve. This condition mostly affects children. The presence of large kidney stones can also obstruct the flow of urine, thereby making one susceptible to a kidney infection. In case of older men, an enlarged prostate can be a contributing factor. The common symptoms of pyelonephritis include:

Flank pain
Pain in the back or groin
Painful urination
Frequent urination

Perinephric Abscess

A perinephric abscess refers to a pocket of pus in the perinephric space, which is a part of the retroperitoneal space that contains the kidney, renal vessels, adrenal glands, fat, and proximal ureter. The formation of an abscess in this area is mostly associated with a urinary tract or bladder infection that spreads to the kidney or the area around it. In majority of cases, kidney stones and urinary tract obstruction are the contributing factors. Structural defects in the urinary tract, diabetes, or trauma are some of the other risk factors. The symptoms of this condition include:

Flank pain
Abdominal pain that radiates to the groin or leg

Acute Renal Arterial Occlusion

Blockage of the artery that supplies blood to the kidney could also have an adverse effect on the kidney function. This could occur due to the formation of a blood clot in the artery. Problems are more likely to arise if the other kidney is not functioning properly. At times, the affected individual may not experience pain. However, if pain is experienced, there's a sudden onset. This condition might cause the following symptoms:

Back pain
Flank pain
Decreased urine output
Pain in the abdomen
Blood in the urine

How is Murphy's Punch Sign Conducted

Each of the kidneys is located anterior to the costovertebral angle in the retroperitoneal space. CVA tenderness can be checked by tapping on the CVA angle. To perform this test, the physician would follow the steps given below:

Ask the patient to either sit up or lie down in a prone position
Place the palm of the nondominant hand on the costovertebral angle at the back
Curl the dominant hand into a fist and strike the palm of the nondominant hand with the ulnar surface of the dominant hand

The physician must not use excessive force. He/she should use just enough force to give the palm a percussive thump. The patient should only feel a gentle thud. The test is negative if the patient experiences just a thud without any pain.

If the patient experiences pain and tenderness during the percussion of the CVA, it might be a sign of renal involvement. In such cases, diagnostic procedures such as palpation of the kidneys, auscultation, renal ultrasound, renal angiography, blood tests, blood culture, urinalysis, urodynamic studies, CT scan, etc., can be conducted to confirm the diagnosis. Though CVA tenderness is often associated with kidney disease, it can also be associated with a musculoskeletal condition.

Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.