(a) At the level of the distal part of the distal radioulnar joint. Entry points A, B, C, and D are shown. Insertion from any of these points does not result in contact between the needle and the median nerve. *Median nerve. (b) At the level of the distal wrist crease. Entry point E, which is in line with the fourth ray, is shown. Insertion from this results in contact between the needle and the ulnar artery. (c) At the level of the distal part of the distal radioulnar joint. The range of angles provided by points A and C, insertion at which prevents contact between the needle and the neurovascular structures, is shown.