Awareness of these potential artifacts will result in a more specific sonographic examination and will accurately guide the referring physician toward appropriate patient treatment. The importance of other imaging modalities is also emphasized to ensure that a correct diagnosis is obtained whenever the sonographic findings are inconclusive.

We report the case of dicephalic conjoined twins discovered incidentally on a routine ultrasound at 24 weeks of gestation. There were 2 heads and a neck that fused with 1 thorax, but the spines continued all the way to the coccyx. The spines were connected medially by a fused rib, and laterally, there were ribs that went around the thorax in a more normal fashion. Antenatal ultrasound images are supplemented by postnatal photographs and x-rays.