animals

Thursday, November 09, 2006

And in like manner

the parts of the lesser one of the two chief
blood-vessels, designated the aorta, branch off, accompanying the
branches from the big vein; only that, in regard to the aorta, the
passages are less in size, and the branches very considerably less
than are those of the great vein. So much for the veins as observed in
the regions above the heart.

The part of the great vein that lies underneath the heart
extends, freely suspended, right through the midriff, and is united
both to the aorta and the backbone by slack membranous communications.
From it one vein, short and wide, extends through the liver, and
from it a number of minute veins branch off into the liver and
disappear. From the vein that passes through the liver two branches
separate off, of which one terminates in the diaphragm or so-called
midriff, and the other runs up again through the armpit into the right
arm and unites with the other veins at the inside of the bend of the
arm; and it is in consequence of this local connexion that, when the
surgeon opens this vein in the forearm, the patient is relieved of
certain pains in the liver; and from the left-hand side of it there
extends a short but thick vein to the spleen and the little veins
branching off it disappear in that organ. Another part branches off
from the left-hand side of the great vein, and ascends, by a course
similar to the course recently described, into the left arm; only that
the ascending vein in the one case is the vein that traverses the
liver, while in this case it is distinct from the vein that runs
into the spleen. Again, other veins branch off from the big vein;
one to the omentum, and another to the pancreas, from which vein run a
number of veins through the mesentery. All these veins coalesce in a
single large vein, along the entire gut and stomach to the oesophagus;
about these parts there is a great ramification of branch veins.