Median nerve and medial cords of the brachial plexus, courses through the anterior part of arm, forearm, and hand, and terminates by supplying the muscles of the hand. After receiving inputs from both the lateral and medial cords of the brachial plexus, the median nerve enters the arm from the axilla at the inferior margin of the teres major muscle. It then passes vertically down and courses lateral to the brachial artery between biceps brachii (above) and brachialis (below). At first, it is lateral to the artery and lies anterior to the elbow joint; it then crosses anteriorly to run medial to
Brachial plexus block useful in providing anesthesia and postoperative analgesia for surgery to the elbow, forearm, wrist, and hand. The axillary block is also the safest of the four main approaches to the brachial plexus, as it does not risk paresis of the phrenic nerve, nor does it have the potential to cause pneumothorax. In the axilla, the nerves of the brachial plexus and the axillary artery are enclosed together in a fibrous sheath which is a continuation of the deep cervical fascia. The easily palpated axillary artery thus serves as a reliable anatomical landmark for this block, and the injection of local