Cobra Head (Snake Head) Ureter

Thomas Canigiani ¹ (Rontgeninstitutes des Kaiser Fronz-Josef-Spitales in Wein) is said by some to have made the first roentgenographic diagnosis of a ureterocele ² . However, it was John Hellstrom, who reported 15 cases in the 1937 Acta Radiologica, who described the schlangenkopf (snake head or cobra head) picture seen by urography as pathognomonic for the presence of a ureterocele ³ (Figure 1). He emphasized that failure to see the snake head did not exclude the possibility of a ureterocele. The ‘cobra head’ represents the dilated terminal portion of the ureter as seen by excretory urography or by cystoscopy. The dilatation may be caused by an abnormally small ureteral orifice or abnormal emptying due to an ectopic position. Figure 1 ‘Bilateral ureteroceles show typical cobra-head deformity.’ Reprinted from Thompson and Kelalis<xref ref-type="bibr" rid="ref17_5"> ⁵ </xref>. Ureterocele. <italic>J. Urol.,</italic> 1964, 91, 488–92, with permission of Williams & Wilkins https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003076568/34c29fd5-5662-4e8f-b58c-badd7fa5d724/content/fig17_1_B.jpg"/>