UMBILICAL HERNIAS, UMBILICAL ABSCESSES, AND URACHAL FISTULAS - SURGICAL CONSIDERATIONS

摘要

The umbilicus is the remnant of the fetal-maternal connection. At birth, this structure consists of the paired umbilical arteries, a single umbilical vein, and the urachus. Prior to birth, the umbilical vein serves as the source of oxygenated blood to the fetus via the liver and the ductus venosus/portal vein. The paired umbilical arteries are branches of the internal iliac artery and carry waste materials and unoxygenated blood to the placenta. The urachus is the connection from the fetal bladder to the allantoic sac. Following a normal delivery, the smooth muscle that surrounds the umbilicus contracts in response to the stretching of the cord at parturition. Separation of the umbilical cord allows the umbilical arteries and urachus to retract into the abdomen, where they close by smooth muscle contraction.(11) The umbilical vein and remnants of the amniotic membrane remain outside the body wall but rapidly collapse in association with smooth muscle contraction; the umbilicus therefore shrinks and shrivels. The umbilical stalk normally dries and thins out by 3 to 4 days post-delivery. The scabbed-over and dessicated umbilical stalk should be totally eliminated by 3 to 4 weeks of age.(18)