hello everyone this is dr sam and today we will study umbilical cord appearances on ultrasound the umbilical cord connects the placenta to the fetus and provides blood supply here we can see a cross section of the umbilical cord it is the transverse view we can see how many vessels it contains the one with the larger diameter is the umbilical vein and these two with smaller diameters are the umbilical arteries so we have two arteries and one vein and the umbilical cord is protected by a substance known as wharton's jelly and over here we can see the umbilical cord entering the fetus at the umbilicus on the abdomen sometimes there may only be a single umbilical artery present here we can see only one umbilical artery in transverse view in its cross section on color doppler we can further investigate a single umbilical artery first we need to locate the bladder and we can see the umbilical arteries on both sides of the bladder the lateral sides these are the umbilical arteries they carry deoxygenated blood from the fetus to the placenta so this blood is going out of the fetus away from the fetus towards the placenta and it is going away from the probe so that's why we have a blue color in doppler and over here we can see one umbilical artery is missing the color doppler shows flow on only one side of the bladder so this is a single umbilical artery now we move on to umbilical cord insertion normally the umbilical cord should enter the placenta at its center but in the case of eccentric cord insertion the accord enters the placenta near the placental edge instead of the center here is the placental edge and it is entering near the placental edge in marginal cord insertion the umbilical cord enters the placenta at its margin or the placental edge instead of the center and the eccentric cord insertion will be over here a velamentous cord insertion is a more serious abnormality in which the umbilical cord will insert into the amniochorionic membranes instead of directly into the placenta the blood vessels travel through these membranes and then reach the placenta these blood vessels are not protected by wharton's jelly that's why they are more prone to rupture in this image the umbilical cord is inserting into these membranes and here is the placenta so this is also a velamentous cord insertion a vasa previa occurs when there are fetal vessels overlying the internal cervical os these blood vessels are also not protected by wharton's jelly now it is different from a funic presentation in which the umbilical cord overlies the cervix we can see the umbilical cord moving and floating in the amniotic fluid and we can also see the wharton's jelly and this presentation may resolve over time whereas in vasa previa we do not see any part of the umbilical cord floating in the amniotic fluid here is a transvaginal view showing a normal image and a vasa previa here there are fetal blood vessels overlying the internal cervical os and in the normal image there will be no fetal blood vessels present here umbilical cord cysts can also occur most commonly they occur in the first trimester here in the normal image you can see a normal umbilical cord and over here you can see an anechoic cyst with a hyperechoic border this is an umbilical cord cyst umbilical vein varix is a focal dilatation of the intra-abdominal part of the umbilical vein we will see an anechoic structure near the bladder this is the dilatation of the umbilical vein and it usually measures around nine millimeters in diameter when we apply color doppler we can see internal flow and we can distinguish it from a cyst a persistent right umbilical vein occurs when the intrahepatic component of the umbilical vein curves towards the stomach instead of curving to the right side here you can see the umbilical vein curving towards the right side and over here it is curving towards the left side towards the stomach thank you so much for watching please subscribe and stay tuned for more imaging videos