he tendon of the
biceps, a portion of which has been cut away; and the venous vessel, F
B, which usually occupies the track of the artery, is pushed a little to
the inner side. While opening any part of the vessel, F B, which
overlies the artery, it is necessary to proceed with caution, as well
because of the fact that between the artery, C, and the vein, F B, the
fascia alone intervenes, as also because the ulnar artery is given off
rather frequently from the main vessel at this situation, and passes
superficial to the fascia and flexors of the forearm, to gain its usual
position at K, Plate 15. I have met with a well marked example of this
occurrence in the living subject.

The cephalic vein, D, is accompanied by the external cutaneous nerve,
which branches over the fascia on the outer border of the forearm. The
basilic vein, B, is accompanied by the internal cutaneous nerve, which
branches in a similar way over the fascia of the inner and fore part of
the forearm. The numerous branches of both these nerves interlace with
the superficial veins, and are liable to be cut when these veins are
being punctured. Though the median basilic, F, and the basilic vein, B,
are those generally chosen in the performance of the operation of
bleeding, it will be seen, in Plate 15, that their contiguity to the
artery necessarily demands more care and precision in that operation
executed upon them, than if D, the cephalic vein, far removed as it is
from the course of the artery, were the seat of phlebotomy.

As it is required, in order to distend the superficial veins, D, B, F,
that a band should be passed around the limb at some locality between
them and the heart, so that they may yield a free flow of blood on
puncture, a moderate pressure will be all that is needful for that end.
It is a fact worthy of notice, that the excessive pressure of the
ligaturing band around the limb at A B, Plate 15, will produce the same
effect upon the veins near F, as if the pressure were defective, for in
the former case the ligature will obstruct the flow of blood through the
artery; and the vein, F, will hence be undistended by the recurrent
blood, just as when, in the latter case, the ligature, making too feeble
a pressure on the vein, B, will not obstruct its current in that degree
necessary to distend the vessel, F.

Whichever be the vein chosen for phlebotomy at the bend of the elbow, it
will be seen, from an examination of Plates 15 and 16, tha