[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Abdomen](https://durgical.com/en/clinical-exam/#a-abdomen) › Costovertebral angle tenderness (fist percussion) [Clinical exam](https://durgical.com/en/clinical-exam/) · [Abdomen](https://durgical.com/en/clinical-exam/#a-abdomen) # Costovertebral angle tenderness (fist percussion) - Sign A gentle blow with the fist over a hand laid on the lower back, over the kidney; marked pain suggests an inflamed or blocked kidney. Updated 2026-11-01 **See it in 3D:** [Kidneys](https://durgical.com/en/anatomy/kidney/) · [Ribs (back part)](https://durgical.com/en/anatomy/ribs/) · [Quadratus lumborum](https://durgical.com/en/anatomy/quadratus-lumborum-muscle/) · [Ureters](https://durgical.com/en/anatomy/ureter/) ## Key points - Location: the angle between the twelfth rib and the spine (lateral edge of the paraspinal muscles), on each side. - Technique: the palm of one hand on the angle and a blow with the ulnar side of the other fist; never strike hard directly. - Compare with the other side; positive if it causes sharp pain the patient recognizes. - Suggests acute pyelonephritis, an obstructing kidney stone, perinephric abscess or hydronephrosis. - Nurses record it together with fever, urinary symptoms and blood in the urine. ## What it is The costovertebral angle is the angle formed by the twelfth rib and the spine on each side of the back; the kidney lies just beneath it. Renal fist percussion means striking this area indirectly to jolt the kidney. Sharp pain that reproduces the patient's symptom is a classic sign of pyelonephritis and also appears with an obstructing stone. ## The anatomy it tests - The kidney is retroperitoneal; its upper pole is shielded by the eleventh and twelfth ribs and its back rests on the quadratus lumborum and psoas. - Percussion sends a jolt to the renal capsule; when the kidney is inflamed or distended by obstruction, the stretched capsule hurts. - The costovertebral angle lies between the twelfth rib and the lateral edge of the erector spinae muscles. ## How to elicit it - Patient sitting and leaning slightly forward with the back uncovered; the examiner behind. - Find the twelfth rib and the spine; the angle is where they meet, lateral to the paraspinal muscles. - First press with the fingertips to check for tenderness to simple pressure. - Lay the palm of one hand flat over the angle. - Strike the back of that hand with the ulnar side of the other fist, with moderate force. - Repeat on the other side and compare; watch the face and ask where the pain was felt. - If the patient cannot sit, examine in the lateral decubitus position. ## What a positive result means - Positive: sharp, one-sided pain on the affected side that reproduces the symptom. - With fever, chills and urinary symptoms: acute pyelonephritis. - With colicky pain spreading to the groin and blood in the urine: kidney or ureteral stone with obstruction. - False positives: lumbar musculoskeletal pain, rib fracture, shingles; flank pain may also come from the gallbladder, liver or bowel. - A negative result does not exclude upper urinary tract infection, especially in older adults. ## Usefulness and limits - In words: moderate sensitivity and specificity; interpret it with urinalysis and urine culture. - Ultrasound or CT are requested if obstruction or abscess is suspected or if the patient does not improve. ## Memory aid Kidney behind the last rib: flat hand as a shield, fist as a bell; if pain rings, the capsule is tight. ## Test yourself Think of the answer, then tap the question to see it. ## Which structures form the costovertebral angle? The twelfth rib and the spine, on each side of the back. ## How is renal fist percussion done? Lay the palm of one hand over the costovertebral angle and strike its back with the ulnar side of the other fist, comparing both sides. ## Why does an inflamed kidney hurt on percussion? Inflammation or obstruction distends the renal capsule, and the jolt of percussion stretches it further. ## What else can cause costovertebral angle tenderness? Lumbar musculoskeletal pain, rib fractures, shingles and, by referral, gallbladder or bowel disease. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/clinical-exam/costovertebral-angle-tenderness/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Kidneys](https://durgical.com/en/anatomy/kidney/) - [Ribs (back part)](https://durgical.com/en/anatomy/ribs/) - [Quadratus lumborum](https://durgical.com/en/anatomy/quadratus-lumborum-muscle/) - [Ureters](https://durgical.com/en/anatomy/ureter/) ## Related - [Kidney palpation: bimanual palpation and ballottement](https://durgical.com/en/clinical-exam/kidney-palpation-bimanual-palpation-and-ballottement/) - [Abdominal percussion: liver span and tympany](https://durgical.com/en/clinical-exam/abdominal-percussion-liver-span-and-tympany/) - [Abdominal regions and quadrants: what lies under each](https://durgical.com/en/clinical-exam/abdominal-regions-and-quadrants-what-lies-under-each/) - [Acute abdomen and peritoneal irritation](https://durgical.com/en/clinical-exam/acute-abdomen-and-peritoneal-irritation/) ## Related conditions - [Acute pyelonephritis](https://durgical.com/en/conditions/acute-pyelonephritis/) - [Kidney stones (urolithiasis)](https://durgical.com/en/conditions/kidney-stones/) [← All of the clinical exam](https://durgical.com/en/clinical-exam/) Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis. Sources: [Costovertebral angle](https://en.wikipedia.org/wiki/Costovertebral_angle) (Wikipedia, 2026); [Flank pain: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/003113.htm) (U.S. National Library of Medicine, 2025). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/clinical-exam/costovertebral-angle-tenderness/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/costovertebral-angle-tenderness/