This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
Posterior cord of brachial plexus is formed by 
Select and explain. 
A. Ventral division of upper trunk, B. Dorsal division of upper trunk, C. Ventral division of upper, middle and lower trunk, D. Dorsal division of upper, middle and lower trunk
D: Dorsal division of upper, middle and lower trunk
Answer: D: Dorsal division of upper, middle and lower trunk 
Explanation: 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 Chaurasia's Human Anatomy , seventh edition , volume 1 , pg. no., 57.