Picture of the Month.

The article presents a three-dimensional power Doppler ultrasound image of right-sided aortic arch with vascular ring and aberrant subclavian artery. Two typical forms of a right aortic arch can be distinguished, which in one condition a vascular ring is found called U-sign prenatally. The prenatal diagnosis showed that the trachea and esophagus are entrapped between the arch and the left ductus arteriosus.