The Umbilical Cord or Funis

The Umbilical Cord Or Funis

This forms the connection between the fetus and the placenta. It is composed of a jelly-like material known as the Wharton’s jelly covered with a single layer of amniotic epithelium and stratified cubical cells. It contains one large umbilical vein which carries oxygenated blood from placenta to the fetus. Two arteries which is a continuation of the hypogastric arteries, wind round the vein and carry deoxygenated blood from the fetus to the placenta. The cord is about 50cm in length regarded short if less than 40cm but the length varies greatly. It may be as short as 7.55cm or as long as 2m. It is not of uniform thickness but is as thick as the little finger. There may be excessive collection of Wharton’s jelly known as “False knot”. The cord is attached to the placenta at the centre.

The false knot is not harmful but True knot which is very uncommon can be very dangerous. It results from excessively long cord & excessive movement. Short cord can cause delay in descent of the presenting part and premature separation of placenta. Excessively long cord can predispose to cord round the neck, body of the fetus, cord prolapse or True knot.

Anatomical variations of the placenta & the Cord

1.           Succenturiate Placenta: An accessory lobe of the placentais attached to the membranes, blood vessels run through the membrane to it. If retained may lead to PPH. It can be diagnosed with a hole in the membrane with blood vessels running into it.

2.           Circumvallate Placenta: this is a situation where chorionand Amnion form a double layer. It is seen as an opaque ring on the fetal surface. It is of no significance.

3.           Battledore Insertion of the Cord: the cord is attached to theedge of the placenta. Looks like a table tennis bat.

4.           Velamentous insertion of the cord: The cord is inserted intothe membranes some distance away from the edge of the placenta. The umbilical vessels run through membranes from the cord to placenta. It causes no harm to the fetus in a normally situated placenta, but may separate during the active management of the third stage of labor.

5.           Bipartite placenta: The placenta divides into two separatesegments the cords join together shortly after the segments. When it divides into three, it is known as Tripartite placenta.

6.           Placenta Accrata: The placenta embeds beyond the normallevel. Separation becomes impossible.

7.           Placenta Fenestrate: Abnormal hole appear in the middle ofthe placenta it may be wrongly taken for missing lobe.

8.           Vasa Praevia: If the placenta is low-lying the vessels maypass across the OS. In this case there is danger to the fetus as the vessel can be torn when the membranes rupture (e.g. artificial rupture of membrane) leading to severe and rapid haemorrhage and rapid exsanguinations of the fetus. This is suspected when onset of haemorrhage coincides with rupture of the membranes.

Diseases of the Placenta

1.           Hydatidiform mole: A poliferative cystic degradation of the chorionic villi.

2.           Calcareous degeneration: Associated normal degerative process of the placenta. The maternal surface is rough to touch and white gritty substance like broken egg shells form opaque on it.

3.           Infarcts: Small whitish area of dead tissue found on the maternal surface. It results from necrotic chorionic villi. It can be found in cases of Pre-Eclampsia Essential hypertension and prolonged pregnancy.

4.           Oedematous placenta: This condition is found in hydrops fetalis when the placenta is large, pale with fluid oozing out from it.

5.           Syphilitic placenta: the placenta is greasy –lookin g and may weigh as much as one quarter of the weight of the fetus.