Prenatal ultrasound images of normal three vessel umbilical cord

(A) Transverse view of a normal umbilical cord shows the characteristic "Mickey mouse" appearance with two arteries (a) and one vein (v) surrounded by the Wharton's jelly. Upper image: conventional two-dimensional ultrasound. Middle image: color Doppler ultrasound shows blood flow in different directions (arteries in red, vein in blue). Lower image: power Doppler ultrasound highlights the presence of angle-independent blood flow signals.
(B) Longitudinal view of a three-vessel umbilical cord shows the arteries (a) looping around the vein (v). Upper image: conventional two-dimensional ultrasound. Lower image: color Doppler ultrasound (arteries in red, vein in blue).