Objective: Adnexal torsion is a common gynecological emergency whose prompt diagnosis is essential because a delay may lead to ovarian dysfunction. Although the whirlpool sign is reliable for diagnosing ovarian cyst torsion, technical difficulties hinder its use by sonographers. Here we developed a systematic approach to visualizing this sign by focusing on the fact that torsion arises from the space between the uterus and the pelvic wall. One must determine the origin of the torsion via transverse imaging of the uterus and follow the twisted ligaments to the ovarian cyst.Patients and Methods: Two women aged 56 (Case 1) and 28 years (Case 2) visited our hospital with lower abdominal pain. Transvaginal ultrasonography showed a 7-cm right ovarian cyst in Case 1 and a 5-cm cyst in the Douglas pouch in Case 2; normal bilateral ovaries and the whirlpool sign were detected in both cases. Under laparoscopic guidance in Cases 1 and 2, an ovarian cyst and a paraovarian cyst were confirmed and removed.Results: Our step-by-step method allowed us to identify the whirlpool sign and confirm adnexal torsion, leading to prompt surgery in both cases.Conclusion: Using a systematic procedure helps less experienced practitioners detect the whirlpool sign.