Portal Vein: Tributaries And Special Features

PORTAL VEIN (HEPATIC)AFORMATION WITH LEVELPortal vein is formed at the level ofthe 2nd lumbar vertebrae by thejunction of the superior mesenteric and splenic veins theunion of these veins taking place in front of theinferior vena. cara and behind the neck of pancreas.(B)COURSE(i) the It assends upwards and to the right behindDIPANKAR RAYof pyloric part of stomach and 1st partdhodenum.(ii) It then ascends in the right free margin of the lesseromentum. On reaching the portatreparts it divides intotwo divisions :(13Right Division - It enters the right lobe of the liver, but beforedoing so generally receives the cystic vein.It lobe. supplies the right lobe of liver except caudate and quadrateIt is now divisions said of that these 2 lobes are Supplied by boththe of demarkation the portal vein. as the development linepasses through these lobes.2Left Division - It is longer but the smaller calibre thanand liver. quadrate lobes., and then enters the left lobe of thethe right, gives branches to the caudate.It is connected :Human Anatomy For Exam(a) With which umbilicus by the ligarentum teres of the liver,represents the obliterated umblical vein.(b)With inferior the vena cana by ligamentum venosum whichrepresents obliterated ductus venosus. PORTAL VEIN (HEPATIC)Cont.(c)RELATIONS(a) At porta hepatis (From anterior to posterior)Two hepatic ducts. (ii) Two divisions of portal vein.(iii) Two divisions of hepatic artery with sympatheticplexus and lymph vessels.forming the hepato-biliary or Glisson's capsule.All these are surrounded by a fibro-faky tissuebyIn right free margin of lesser omentumHuman AnatomyFor Exam(i) Common hepatic duct and bile duct_ , lying on the rightof the heparic artery.(ii) Hepatic artery - lying on the left of the duct.(iii) Portal vein - lying in between and posterior to boththe duct and artery.lymph nodes, lymph vessels, sympathetic plexusAll these 3 Structures together with the hepaticand areolar tissues.(e)Part of the vein below the lesser Omentum-1. Anterior2. Posterior(i) Pyloric part of Stomach.(i) Inferior vena cava.(ii) Duodenum (1st part).(iii) Neck of Pancreas.(ii) Right crus of diaphragmin Beginning of gastro dudenal Art.3. To the Right4. To the left(i) Gastro -duodenal Artery.Abdominal aorta withII Bile ductorigins of coeliac, andsuperior mesenteric artery,surrounded by the coeliac plexus. PORTAL VEIN (HEPATIC)3Callateral Anastomosis between Portal and Systemic Veins(1)At the lower end of OesophagusOesophageal tributaries of left gastric vein (portal system)Communicate veins. with Berophageal tributaries of hemi- azygos(2)At the lower end of Rectum and Anal CanalSuperior rectal vein (porta System) Communicates with middleline of anal canal.and inferior rectal veins (Pystemic Vein) close to the pectinateDIPANKAR RAY(3)At the UmbilicusThe paraumbilical rein (portal system)From above, Superior epigastric and lateral thoracic veins.communicates with the following Systemic veins-From below, Superficial epigastric and inferior epigastric veins.From the sides, Posterior intercostal and lumber veins.4Behind the Peritorreum of the posterior abdominal wallSplenic and colic veins (portal system) communicate with leftrenal vein and other tributaries of inferior vena cavaby a number of small veins.5At the Bare Area of LiverHumanAnatomyFor ExconPortal veins radicles of liver a number communicate of with the diaphragmatic(systemic ) by small veins.6In the Falciform ligament Para umbilical vein (portal system)numerous small veins.communicates within the diaphragmatic veins (systemic) byTAt the Fissure for Ligamentum venosumLeft branch of partal rein at the porta hepatis Communicatesin foetal life with inferior vena cara via ductus venosus.form ligarentum venosum.After birth, dustus vencsus is fibrosed to8In the Posterior wall of vaginaThe superior rectal vein (portal system) communicates withthe vaginal venous plexus (Systemic) PORTAL VEIN (HEPATIC)4TRIBUTARIES OF PORTAL VEIN1. Superior MesentericFORMATIVEOccasionalvein2. Splenic VeinTRIBUTARIESTributariesReceived byInferior mesenteric Vein3. Right gastric veinthe trunk4. Left gastric veinofRight -gastro epiploic VeinPORTAL VEINPre-pyloric vein.5. Cystic VeinReceived by the6. Paraumbilical Vein2 divisions ofportal veinPORTAL VEIN FEATURESHerman Anatomy ForExam1The vein begins as vein but ends in capillary like vesselstermed Sinusoids2 Portal vein begins from the inestinal capillaries then enters theliver and via the heparic Sinusoids its venous bloodreaches the central vein. which is the smallest tributary ofhepatic vein.through the capillary system. Portal vein and its tributariesIn paral system of rein blood is thus passingare devoid of valve.(3) About 1/3rd of total blood (body) is present in parta) vein & tributaries.(4) Portal vein provides 65-80% nutrition of liver, rest is provided byhepatic artery which is also supplies O2.5 Portal pressure - 6-8 mmHg. Hepatic venous pressure 5mrHg Soblood flows from portal to systemic side.6Portal vein is formed by the superior mesenteric vein andSplenic vein But when venous blood of this 2 veins arepassing not occur. through the portal vein mixing of blood doesRight branch of portal vein mainly carries venous bloodvia superior mesenteric vein which is rich in nutrition.Via left branch of portal vein.Splenic blood mainly circulated in the left bbe of liver-This explains why the right lobe of liver is larger than Left Lobe/