Development of venous system

ANATOMY

1. Development of Venous System S.B. Rauniyar

2. Development of primitive veins  Visceral & somatic 1.Vitelline veins ( omphalomesentric ) -- arise from capillary plexuses o the splanchnic mesoderm around  yolk sac. 2.Umbilical veins  convey oxygenated blood from placenta. 3.Cardinal veins drains from the body wall.  ant.C V--cephalic ,upper limb bud.  post.C V— caudal,lower limb bud CCV/duct of Cuvier

3. Development & fate of Umbilical veins With the appearance of hepatic bud right UV disappears. Left UV joins at left branch of portal vein. With increase of placental circulation it causes a direct communication betn.left UV & right hepato cardiac channel -> Ductus venosus .

4. Development & Fate of Vitelline Veins Hepatic bud –divides in to infra, intra & supra hepatic parts INFRA HEPATIC PARTS Forms 3 transverse anastomosis - Cephalic ventral - Middle dorsal - Caudal ventral Spleenic vein & sup.mesentric vein joins at left end of middle dorsal anastamosis .

5. Formation of trunk of PORTAL VEIN. Right branch of portal vein. Left branch of portal vein ->It receives oxyganated blood from left umbilical vein which ends here.

6. INTRA HEPATIC PART With the development of liver-proximal parts VV & UV broken in to capillary plexus & joins to form hepatic sinusoids Afferent vessels— Venae advehentes, persists as intra hepatic br. Of portal vein Efferent vessels– Venae revehentes & forms the tributeries of hepatic veins.

7. SUPRA HEPATIC PART Transverse sub diaphragmatic anastomosis connects both VV. A new vessels grows betn. Subdiaphragmatic & sub hepatic cephalic ventral anastomosis. After left part of subdiaphragmatic anastomosis & adjoining part of left VV disappear. Right part of VV enlarges to form common hepatic vein.

8. Development & fate of ant. Cardinal vein Cervico thoracic Part. It receives intersegmental veins from body wall. One enlarged vein from upper limb -Subclavian vein.

9. Continued ant. Cardinal vein

10. Development of –SVC,BCV & IJV

11. Development of – leftsup. Intercostal vein &2 nd ,3 rd intercostal veins

12. Applied anatomy of SVC 1.Double SVC-Persistent left ant.& CCV. 2.Left SVC-caudal part of the right ant. Cardinal vein & CCV disappear.

13. Development & fate of post.Cardinal vein

14. Development of IVC, Right & Left Common iliac vein .

15. Development of Renal, Suprarenal & Gonadal Veins

16. Azygos vein- -vein of right azygos line --right post. Cardinal vein. Hemiazygos & Acc. Hemiazygos —left azygos --post aortic anastmosis

17. Applied Anatomy of IVC 1.Double IVC Occurs below the level of renal veins Persistence of both sub cardinal & supra cardinal on right side ( fig.B ) Left supra cardinal vein fails to regress.

18. 2.Left IVC Fig.E -Infra renal part of IVC present on left side only. 3.Absence of hepatic segment of IVC Fig.G -Non development of anastomosis betn . the right sub cardinal & hepatocardiac channel.

19. 4.Pre ureteric vena cava Here IVC lies post. to right ureter . Caused by –when infra renal part of IVC develops from right sub cardinal & post.cardinal vein instead of supra cardinal vein.(lies post.to ureter )