The second point above brings out an interesting observation on essential differences between ultrasound guided nerve blocks and placement of the needle using either nerve stimulation or parasthesias. Common wisdom holds that after correctly placing the needle using parasthesias or nerve stimulation, the needle should be held rigidly in place while the injection occurs. This is a maneuver designed to increase safety by minimizing the chance of needle migration into a vascular space or other dangerous or counterproductive position. Under ultrasound observation one often notes that rigidly holding a needle in place during injection of a significant volume of solution sometimes results in the displacement of the needle to into a disadvantageous position by deformation of the tissue space in which the needle resides. In fact, this has been seen so many times in our series it seems clear that an adequate nerve block requires much less volume and was previously assumed.