Endometrial deviation generally refers to a deviation of the uterine cavity line, which is mostly caused by uterine pathology. For example, if the cavity line deviation is accompanied by uneven echogenicity of the myometrium, it may be caused by an adenomyoma compressing the uterine cavity. In the case of a cavity line shift, a uniform echogenicity with an enveloping mass can be seen, possibly due to a localized cavity line shift caused by an intermyometrial myoma protruding into the uterine cavity. There are also endometrial pathologies that can cause endometrial deviation, such as endometrial polyps and endometrial cancer, which can cause the cavity line to be out of center and deviate. If endometrial shift occurs, the cause needs to be further investigated and if necessary, hysteroscopy can be performed to clarify.