Las 
DEVELOPMENT OF THE VEINS. 887 
The portions of the cardinal veins lying below the transverse anastomosis which 
becomes the left common iliac vein remain ; that on the right forms the right internal and 
common iliac veins, but the left forms only the left internal iliac vein and a small part of 
the left common iliac vein, for the transverse anastomosis commences on the left side 
almost opposite the point of 
entrance of the external iliac i 
vein, whilst it terminates on ( “Lateral sinus 
the right side at a higher = 
level. 
From the left common 
iliac vein to the renal vein 
the cardinal vein of the left 
side disappears ; that on the 
right side becomes the lower BS 
part of the inferior vena Ssubclavian___ 
cava, to which the blood ie ene 
passes from the left side of Higbeianouinate a 
the abdominal wall by means 
of small transverse anasto- — Superior vena cava 
mosing channels which existed 
between the cardinal veins, 
and which persist as the \ 
terminal portions of the left Vena azygos major ——+ 
lumbar veins. 
Above the renal veins | 
part of the right cardinal vein 
Internal jugular vein 
— External juzular vein 
™! ; Subclavian 
eae . 
vein 
Left innominate vein 
Left superior intercostal 
vein 
Oblique vein of Marshall 
foray ena azygos minor superior 
Heart 
Vena azygos minor inferior 
é Liver 
persists as the vena aZVZOS ; as Left hepatic vein 
: LS. Right hepatic_ \ 
major, and the left forms vein uu 
c Ductus venosus 
the upper and lower minor ace eh Left branch of 
g “ane oO n ray 
azygos veins and the lower “® AAR at portal vein 
part of the left superior inter- 
costal vein. The azygos minor 
veins open into the azygos Inferior vena cava—>——~ 
major by the two transverse 
anastomosing channels which 
form between the upper parts 
of the cardinal veins. 
The upper part of the in- 
ferior vena cava is developed Spermatic vein 
as an outgrowth from the 
common trunk formed by the 
fusion of the ductus venosus 
with the right hepatic vein. BEDS LENE! 
It grows downwards, behind 
the liver and along the right | 
side of the vertebral column, Right common iliac "_ 
-Umbilical vein 
— Portal vein 
Suprarenal vein 
Suprarenal vein 
Renal vein —= Renal vein 
Spermatic vein 
< Left common iliac vein 
to the interval between the 
kidneys, where it divides into 
two branches, of which the 
right anastomoses with the Right internal iliac vein —} 
right cardinal vein at the | 
level of the renal vein; it 
receives the suprarenal vein, 
Right external iliac vein Left external iliac vein 
Left internal iliac vein 
—Middle sacral vein 
Fic. 606.—DEVELOPMENT OF THE VENOUS SystTEM (Diagrammatic). 
arngh hs Heatran taper- Stage IV. The left wnbilical vein has joined the upper part of the left 
eA detenit Ma acai vitelline vein ; the ductus venosus and the upper part of the inferior 
Se ey ELC I PS seald vena cava have appeared, and portions of the primitive jugular and 
to become the spermatic vein cardinal veins have atrophied. 
of the right side. The left 
branch passes across the front of the aorta below the superior mesenteric artery, and 
unites with the left cardinal vein at the point of entrance of the renal vein. It gives 
off an upper branch which becomes the left suprarenal vein, and a lower which becomes < 
the left spermatic vein. As before pointed out, the left cardinal vein disappears between 
the renal vein and the left common iliac vein, whilst the right remains as the lower part 
of the inferior vena cava. The left division ni the upper part of the inferior vena cava, 
tas. | e 
