I had undergone Usg of KUB. The report says small right renal calculus. What does this mean? Small calculus measuring 3 mm seen in the mid calyx of right kidney. Central echo complexes are normal. No evidence of any less lesion seen on either side. Ureters: No hold up is seen Urinary bladder: Urinary bladder is well distended & normal in wall thickness. No intraluminal pathology or intramural mass lesion seen. Post void bladder shows insignificant amount of residual urine.