Anteverted uterus, negative sliding sign

Pressure is being applied to the uterus by the ultrasound operator’s non-scanning hand, but the contents posterior to the uterus are not sliding smoothly against the posterior uterine serosa. In this case, there is a fixed ovary posteriorly and subtle hypoechoic nodule posterior to the uterus at the level of the internal cervical os, suggesting of deep endometriosis of the torus uterinus. 

For more information: Noninvasive ultrasound diagnosis of endometriosis