THE POSTERIOR VENA CAVA. 619 



It begins in the sublumbar region, at the great mesenteric artery, by the 

 union of three large roots ; it is then directed forwards and a little to the 

 right, traversing the pancreatic ring, below the vena cava, and is afterwards 

 lodged in the great posterior fissure of the liver, where it ramifies by forming 

 the subhepatic veins, whose capillary divisions themselves give rise to the 

 suprahepatic vessels. 



Suprahepatic and subhepatic veins (Fig. 219, VP, VA). These vessels 

 having been already studied in the description of the liver, we need not 

 again occupy ourselves with them, but refer only to a peculiarity incompletely 

 noticed in that description, with reference to the suprahepatic veins. 



We know that these vessels are divided into two categories, according to 

 the arrangement of their openings. The majority enter the vena cava in 

 forming a single confluent placed at the anterior extremity of the fissure in 

 the liver, at the diaphragmatic veins ; the others open separately over the 

 whole extent of the hepatic portion of the venous trunk. In carefully 

 examining the confluent towards which all the veins of the first group 

 converge, we recognise the embouchures of three principal veins, one coming 

 from each of the hepatic lobes, and furnished with three very thick, incom- 

 plete valves. With regard to the vessels of the second group, M. Claude 

 Bernard * considers them to come, for the most part, directly from the sub- 

 hepatic veins, and not from the capillary network formed by the arborisation 

 of these veins in the lobules of the liver. It is true that injections readily 

 penetrate from the vena portae into the vena cava, but they do this quite as 

 much by passing along the large suprahepatic vessels as the canals of which 

 we now speak ; and, besides, if the material forced into the vena portae is 

 mixed with some imperfectly-powdered colouring matter, the injection will 

 arrive colourless, or but slightly tinged, in the suprahepatic vessels and the 

 vena cava. These facts, we see, do not militate in favour of M. Bernard's 



* Lemons de Physiolojic Experimentale.' Paris, 1856. 



Anterior vena cava ; 2, 2, Posterior vena cava ; 3, Right pelvi-crural trunk, 

 divided at the ilio-sacral articulation ; 4, Left pelvi-crural trunk ; 5, Femoral 

 vein ; 6, Obturator vein ; 7, Subsacral vein ; 8, Left testicular vein ; 9, Poste- 

 rior abdominal vein; 10, Renal vein; 11, 11, Ascending branches of the asternal 

 vein ; 12, Vena azygos, with its intercostal branches, and in front the subdorsal 

 venous branch, 13; 14, (Esophageal vein; 15, Dorsal, or dorso-muscular vein; 

 16, Cervical, or cervico-muscular vein ; 17, Vertebral vein ; 18, Right axillary 

 vein, cut at the anterior border of the first rib; 19, Substernal, or internal 

 mammary vein ; 20, Left axillary artery ; 21, Termination of the left cephalic 

 vein ; 22, Left jugular , 23, Right jugular ; 24, External maxillary, or glosso- 

 facial vein ; 25, Coronary vein ; 26, Angular vein of the eye ; 27, Subzygomatic 

 vein ; 28, Posterior auricular vein ; 29, Maxillo-muscular vein ; 30, Internal 

 metacarpal vein ; 31, Median subcutaneous vein ; 32, Radial subcutaneous vein ; 

 33, Posterior radial vein ; 34, Basilic vein ; 35, Plat, or cephalic vein ; 36, 

 Coronary venous plexus, 37, Digital vein; 38, Internal metatarsal vein; 39, 

 Anterior root of the internal saphena vein; 40, Posterior root of ditto; 41, 

 Internal saphena ; 42, Great coronary vein ; 43, Small mesaraic vein ; 44, Djf- 

 ferent branches of the great mesaraic vein ; 45, Trunk of the vena portse in its 

 sublumbar portion, lodged in the pancreas ; 46, The same in the posterior fissure 

 of the liver ; below it is seen entering the substance of the gland. M, Sub- 

 scapular hyoideus muscle cut obliquely in the direction of the trachea ; P, Cervical 

 panniculus turned down to expose the jugular channel ; o, Right auricle of the 

 heart ; A, Posterior aorta ; G, Section of the right lung ; p, Left lobe of the liver 

 behind the section of the diaphragm ; R, Right kidney carried up and forward ; 

 L, (Esophagus; v, Bladder; s, Rectum; T, Thoracic duct; x', Termination of 

 that duct in the confluent of the jugulars. 



