Figure 2

Flowchart for the protocol for manual intramuscular needle placement checked by PSRM as verified by means of ES. Whether or not the needle is positioned correctly after manual intramuscular needle placement checked by PSRM; the needle at this stage will not be removed or repositioned. ES will be initiated at 1.50 mA. A palpable and visible contraction of only the target muscle will be assessed as an ES-true verification. The ES level will be reduced to 1.00 mA if more than one muscle contracts at the same time. If only the target muscle shows a palpable and visible contraction after the ES level is reduced, the needle location will be defined as an ES-true verification. Contraction of a different muscle will be assessed as ES-false verification. When there is no contraction at all, the current will be increased to a maximum of 5.0 mA. If there is still no muscle contraction or a different muscle contracts, or many muscles contract at the same time, this will be defined as an ES-false verification.