Sirenomelia
Definition
Sirenomelia is a lethal birth defect of the lower body characterized by apparent fusion of the legs into a single lower limb. Other birth defects are always associated with sirenomelia, most commonly abnormalities of the kidneys, large intestines, and genitalia.
Description
This pattern of birth defects is associated with abnormal umbilical cord blood vessels. The normal fetus develops two umbilical arteries, which pump blood from the fetus to the placenta, and one umbilical vein, which returns blood from the placenta to the fetus. The umbilical arteries branch off the iliac arteries in the pelvis. The iliac arteries supply the legs and pelvic organs such as the genitalia. Most babies with sirenomelia have only one umbilical artery and one vein. Rarely a baby with sirenomelia can...[The entire page is 1230 words long]
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