What are root values of nerve supplying muscle needed for latter pa of the following action?: (A) C7, C8, (B) C8, T1, (C) C5, C6, (D) C5, C6, C7
Answer is D. 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.