Morphology and Morphometric Study of Placenta and Umbilical Cord with its Vascular Pattern and Comparative Anatomy

Sudha, R (2009) Morphology and Morphometric Study of Placenta and Umbilical Cord with its Vascular Pattern and Comparative Anatomy. Masters thesis, Madras Medical College, Chennai.

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Abstract

The word placenta is a Latin word meaning a flat plate or cake. Placenta represents an extremely intimate parabiotic union of maternal and foetal tissues for the inevitable requirement of the embryo. After the delivery of the foetus the placenta becomes separated from the uterine wall and is expelled with the membranes as the "after birth". Expelled discoidal mass has two surfaces -maternal and foetal and a peripheral margin.In 100 placentae the circular shape was the common form (55%) and oval shape was the next common (30%). Triangular shape (8%), succensuriata (2%), circumvallata (1%), bilobedplacenta (1%), kidney shape (1%), heart shape (1%) and fused placenta (1%) were also observed in this study. The mean diameter of the placenta in 100 specimens is 17.73 cm. The mean diameter of the placenta in complicated pregnancies (17.20 cm) is similar to the uncomplicated pregnancies (17.97 cm). The mean placental diameter is increased in diabetes mellitus and decreased in anaemia and hypertension. The average thickness of the placenta in the present study in 1.9 cm. The thickness of the placenta in complicated pregnancies (1.89 cm) is slightly less than the uncomplicated pregnancies (1.9cm). The thickness of the diabetes mellitus placenta (2.6cm) is greater than the uncomplicated pregnancies and the thickness in hypertension and anaemia is less than the uncomplicated pregnancies (1.5cm). The average cotyledon number in the present study is 18, in normal uncomplicated pregnancies it is 19 and in complicated pregnancies it is 17. The cotyledon number is increased in diabetes mellitus (19) and reduced in hypertension (14). In anaemia ill-defined cotyledons were observed. The average weight of the placenta in 100 cases is 472.49 gms, in complicated pregnancies it is 432.74 gms and in uncomplicated pregnancies it is 490.58 gms. In diabetes mellitus (587.5 gms), weight of the placenta is greater than the uncomplicated pregnancies (490.58 gms). The weight of the placenta in hypertension (388.66 gms) and anaemia (387.5 gms) is less than the uncomplicated pregnancies (490.58 gms). The mean feto-placenta ratio in this study is 6.6 (Complicated pregnancies – 6.5 and uncomplicated pregnancies – 6.7). The feto placental ratio is not much altered in anaemia (6.3), hypertension (6.4) and diabetes mellitus (6.7) when compared to uncomplicated pregnancies. The placental coefficient in this study is 0.15 (complicated-0.16 and uncomplicated is 0.14). The placental coefficient is increased in factors complicating pregnancy such as hypertension (0.15), anaemia (0.15) and not altered in diabetes mellitus (0.14) when compared to normal pregnancies. The average weight of the conceptus in the present study is 3.16 kg (complicated – 2.6 kg and uncomplicated – 3.28 kg). The average weight of the conceptus is reduced in factors complicating pregnancy like intrauterine death, anaemia, and hypertension and increased in diabetes mellitus. In the present study the vascular pattern of the placenta observed were disperse type 40%, magistral 14% and mixed type 44%. In the present study the type of cord insertion observed was central 9%, battledore (marginal) 12%, velamentous type 1.9% and eccentric type 75%, which is the most common in the present study. In all the 100 specimens 2 umbilical arteries and 1 umbilical vein was present. The average length of the umbilical cord is 47.95 cm. The length of the cord in complicated pregnancies is 47.71 cm, which is shorter compared to the normal pregnancies 48.06 cm. The average diameter of the umbilical cord in the present study is 1.132 cm (complicated pregnancies- 1.112 cm, uncomplicated pregnancies- 1.138 cm). In the present study dextral twist was observed to be (right) 2%, compound twist 1.9%, nil twist 0.9%, and sinistral twist (Left) was 95% which was most commonly observed. In the present study 15 % of false knots were observed. Histological study –In hypertensive placenta histology showed numerous syncytial knots, hypermature villi with medial hypertrophy of the blood vessel. Diabetic placenta showed hypovascular large villi with fibrin deposits. Placenta in anaemia showed small villi with narrow intervillous spaces. Silicone gel cast technique revealed 3 disperse type and 2 magistral type of vascular pattern. Contrast study of placental vasculature by angiogram method revealed 3 disperse type and 2 magistral type of vascular pattern. Sheep, goat and cow placentae have cotyledonary type of placenta where as pig has diffuse type of placenta. Only rabbit has discoidal placenta similar to the humans. Weight of the cow placenta is heavier than the human placenta. Morphology and morphometric study of the placenta and umbilical cord with vascular pattern will be definitely useful to the vascular surgeons operating intrauterinely to correct the congenital defects, and the variations observed will be useful to the respective clinicians and anatomist, who are doing further research in this field. Comparative anatomy done in this study will help the Veterinary doctors in their research.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Morphometric Study; Placenta and Umbilical Cord; Vascular Pattern; Comparative Anatomy
Subjects: MEDICAL > Anatomy
Depositing User: Kambaraman B
Date Deposited: 22 Jun 2017 06:21
Last Modified: 22 Jun 2017 10:37
URI: http://repository-tnmgrmu.ac.in/id/eprint/228

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