This section is from the book "Anatomy Of The Arteries Of The Human Body", by John Hatch Power. Also available from Amazon: Anatomy of the Arteries of the Human Body, with the Descriptive Anatomy of the Heart.
The arm being abducted and rotated outwards for the purpose of diminishing the depth of the wound, an incision, about two inches and a half long, may be made over the ulnar margin of the coraco-brachialis muscle, the belly of which may be felt through the integuments. This should be done with much caution, as the integuments are thin in this situation, and the basilic vein may sometimes, though rarely, lie superficial to the brachial aponeurosis; moreover, the internal cutaneous nerve lies here immediately underneath the skin. The fascia being next divided on a director to the same extent, the areolar tissue may be scraped through with the handle of a knife till the artery and nerves are brought into view. The vein formed by the union of the basilic vein with the venae comites, together with the internal cutaneous and ulnar nerves, may be drawn to the inside, and the median nerve to the outside, and the needle passed from within outwards. The separation of the artery and nerves will be facilitated by flexing the limb.