The anechoic zone seen in the adnexa by ultrasound is often caused by the following reasons: first, pathological cysts on the ovary, this condition will often be greater than 5cm in diameter in the anechoic zone, which is definitely bad clinically and needs to be given surgery for treatment. The second one is an echogenic cyst, which may be physiological, often less than 5 cm in diameter on the ovary, often occurring after ovulation, due to the formation of the corpus luteum, which often shrinks significantly or disappears after menstruation, so no special treatment is needed. Thirdly, there is an echogenic area in the adnexal region, which may also be a follicle, which is good and indicates ovulation of the ovary.