Endometrial detachment is common in menstrual period or a short time after abortion. Now you only describe the examination by B-ultrasound, and I don't know under what circumstances you did it. If it is an examination just after abortion or a menstrual examination, these examinations describe normal performance, and the cervical thickness is slightly thicker than one millimeter, which does not rule out the inspection error.
comments and suggestions:
I suggest that you supplement the examination under what circumstances, whether there is vaginal bleeding now, so that you can further judge whether it is an Arabic 8 or a Chinese 8. If it is abnormal, you should be alert to the possibility of mediastinum in the uterine cavity.