<prompt> What are root values of nerve supplying muscle needed for latter pa of the following action?C7, C8C8, T1C5, C6C5, C6, C7  <response>: Serratus Anterior is responsible for the latter pa of abduction along with trapezius. The long thoracic nerve Nerve of Bell originates from the C5-C7 roots and descends in the axilla, posterior to the brachial plexus, to innervate the serratus anterior muscle. 