Final answer:
The brachial artery is the artery used for the most complete distribution to the upper extremities in autopsied remains, as it subdivides into various branches that supply the arm, forearm, and hand.
Step-by-step explanation:
The artery used to achieve the most complete distribution to the upper extremities in autopsied remains is the brachial artery. This is because the brachial artery supplies blood to much of the brachial region and divides into several smaller branches at the elbow, including the deep brachial arteries, which provide blood to the posterior surface of the arm, and the ulnar collateral arteries, which supply blood to the region of the elbow. Furthermore, as it approaches the coronoid fossa, it bifurcates into the radial and ulnar arteries, which continue into the forearm. These arteries ultimately fuse to form the superficial and deep palmar arches that supply blood to the hand and the digital arteries that supply blood to the digits.