This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The flexure of the elbow is occupied by a number of veins which are of importance from the fact that they are frequently used for purposes of saline infusion, sometimes for blood-letting, and not infrequently they are wounded and give rise to troublesome hemorrhage.
They are made more prominent by allowing the arm to hang and by tying a bandage firmly above the elbow. The "larger part of the blood from the parts below is carried by the superficial veins; hence the largest veins lie directly beneath the skin and can be seen through it.
Their arrangement is not always regular but they follow a more or less general plan. The blood from the radial side of the wrist and forearm is carried by the radial vein. The median vein brings the blood from the anterior surface of the wrist and parts above. There are two veins on the ulnar side, an anterior and a posterior. The anterior carries the blood from the anterior ulnar aspect and the posterior ulnar from the posterior ulnar aspect of the wrist and forearm. All these veins contain valves at intervals of a few inches. The median vein passes up the middle of the anterior surface of the forearm, and just below the lower edge of the bicipital fascia communicates with the deep veins accompanying the radial and ulnar arteries. This communication is large, distinct, and always present (Fig. 300).
The median vein then divides into the median basilic, which passes upward in the internal bicipital furrow, and the median cephalic, which follows the edge of the biceps to the external bicipital furrow. Three or four centimetres above the bifurcation of the median, the median cephalic vein is joined by the radial, and from that point up it is called the cephalic vein.
Fig. 300. - Veins at the bend of the elbow.
The two ulnar veins just below the medial (internal) condyle or sometimes just above it empty into the median basilic vein, which from this point is called the basilic vein. Sometimes the two ulnar veins, anterior and posterior, unite and empty into the median basilic by a common trunk. The median basilic vein passes over the bicipital fascia, which separates it from the brachial artery which lies directly beneath. The median basilic vein (or cephalic when more prominent) is usually chosen for purposes of saline infusion. It lies to the inner side of the biceps tendon and no important structures are liable to be wounded. The terminal filaments of the musculocutaneous nerve pass under the median cephalic vein and are not liable to be wounded. If the median basilic is chosen for infusion or venesection care must be taken not to cut through the bicipital fascia, otherwise a wound of the brachial artery may be produced which may result in the formation of a varicose aneurism or aneurismal varix.
When these veins are wounded the bleeding may be very free. Not only are the superficial parts drained but likewise the deep parts through the communication with the median. We saw one case in which death nearly resulted from such a wound made by a piece of tin. When saline infusion is practised the vein selected is made visible by compressing it above. It is then cut directly down upon and isolated, and the cannula inserted.