Whirlpool sign (testicular torsion)
The whirlpool sign of the spermatic cord is a direct sign of testicular torsion, both complete and incomplete (i.e. <360°). It is considered to be the most specific and sensitive sign for testicular torsion.
Terminology
The term whirlpool sign is used in other contexts: see whirlpool sign (disambiguation).
Radiographic features
A spiral twist demonstrated in the course of the spermatic cord on greyscale ultrasound, either in the external inguinal ring or in the scrotal sac.
See references 1 and 5 for demonstrative videos.