English: Medical ultrasound image showing abnormal vesicoureteral junction and dilated distal ureter resulting in primary vesicoureteral reflux (VUR). Insufficient submucosal length of the ureter relative to its diameter causes inadequacy of the valvular mechanism which prevents reflux. In healthy individuals the ureters enter the urinary bladder obliquely and run submucosally for some distance. Images of resulting hydronephrosis in same case attached below. Provided as-is. Please feel free to categorise, add description, crop.