Final answer:
The carpal region is distal to the brachial region and superior to the popliteal region. It is supplied with blood by the radial and ulnar arteries that fuse to form the superficial and deep palmar arches in the carpal region.
Step-by-step explanation:
The carpal region is anatomically located in the forearm area between the elbow and wrist joints and consists of the carpal bones which make up the wrist. When contrasting the carpal region with the brachial region, which includes the upper arm where the brachial artery is located, the carpal region is distal (or further away) from the midpoint of the body than the brachial region. Therefore, the correct answer to the question 'the carpal region is ______ to the brachial region' would be:
d. superior to the popliteal region.
The brachial artery, which is formed at the bifurcation of the main artery of the upper limb, travels down the arm, paralleling either the radius or ulna and giving off smaller branches. Upon reaching the carpal region, the brachial artery's terminal branches, now known as the radial and ulnar arteries, fuse to form the superficial and deep palmar arches, supplying blood to both the lower arm and carpal region.