Communication

vein joins the superior vena cava and the hemiazygos veinjoins the left brachiocephalic vein. At the distal end of the oesophagus some oesophageal veins join the azygos vein and others, the left gastric vein. A venous plexus is formed by anastomoses between the veins joining the azygos vein and those joining the left gastric veins, linking the general

Paired branches

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Inferior phrenic arteries supply the diaphragm.Renal arteries supply the kidneys and give off branches, the suprarenal arteries, to supply the adrenal glands.Testicular arteries supply the testes in the male.Ovarian arteries supply the ovaries in the female.

The testicular and ovarian arteries are much longer

••

and portal circulations (see Fig. 12.50, p. 321).

Abdominal aortaThe abdominal aorta

than the other paired branches. This is because the testesand the ovaries begin their development in the region of the kidneys. As they grow they descend into the scrotum and the pelvis respectively and are accompanied by their blood vessels.

is a continuation of the thoracicaorta. The name changes when the aorta enters theabdominal cavity by passing behind the diaphragm at the level of the 12th thoracic vertebra. It descends in front of the bodies of the vertebrae to the level of the 4th lum- bar vertebra, where it divides into the right and left com- mon iliac arteries (Fig. 5.44).

When a branch of the abdominal aorta supplies an organ it is only named here and is described in more detail in association with the organ. However, illustra- tions showing the distribution of blood from the coeliac, superior and inferior mesenteric arteries are presented here (Figs 5.45 and 5.46).

Unpaired branchesThe coeliac artery (Fig. 5.44) is a short thick artery about1.25 ern long. It arises immediately below the diaphragm and divides into three branches:

•••

left gastric artery: supplies the stomachsplenic artery: supplies the pancreas and the spleenhepatic artery: supplies the liver, gall bladder and partsMany branches arise from the abdominal

of which are paired and some unpaired.aorta, some

of the stomach, duodenum and pancreas.

Rightinferiorphrenicartery---~~~

~~!----Left inferiorphrenicartery

Righiadrenaal rtery----lm~

·~~!!#,IFfi;=~~IHm[ --~Coeliac artery

..lal;;l;i,._.~t= -~"i-----Superior mesenteriacrtery

Righttesticulaor r----------::l(/

ovarianartery

Figure 5.44 The abdominal aorta and its branches.