i want to ask the causes of nerve block injuries. what is the mechnism. i know that it occurs if the injection is not given at a proper site. but what will be the different mechanisms with which under different circumstances that will cause these injuries at macromolecular levels. and what are thwe possible mistakes that can cause an irreparable damages. i want to know a whole outline about it..... Also under different conditions without doing harm to a patient can we know that something is going wrong.