<prompt> Posterior cord of brachial plexus is formed byVentral division of upper trunkDorsal division of upper trunkVentral division of upper, middle and lower trunkDorsal division of upper, middle and lower trunk  <response>: Cords of brachial plexus are formed by : i The lateral cord - It is formed by the union of the ventral divisions of the upper and middle trunks. ii The medial cord - It is formed by the ventral division of the lower trunk. iii The posterior cord -It is formed by union of the dorsal divisions of all the three trunks. Ref : B D Chaurasias Human Anatomy , seventh edition , volume 1 , pg. no., 57. 