What is the terminal structure of the upper extremity arterial system?

The terminal structure of the upper extremity arterial system is the palmar arch. This structure is formed by the anastomosis of the radial and ulnar arteries as they travel down toward the wrist and hand. The palmar arch supplies blood to the hand and is crucial for the vascularization of the palmar structures, including the muscles, skin, and other tissues.

Both the radial artery and the ulnar artery are key components of the arterial supply to the forearm and hand, but they are not terminal structures since they continue to give rise to branches that contribute to the palmar arch. The axillary artery, which is located in the shoulder area, supplies blood to the upper limb, but it branches into the brachial artery, which further divides into the radial and ulnar arteries before ultimately leading to the palmar arch.

Thus, the correct answer highlights the final convergence point of the arterial supply to the upper extremity, emphasizing the importance of the palmar arch in the overall circulatory system of the hand.