Final answer:
The subclavian artery is named the axillary artery once it crosses under the clavicle and over the 1st rib. The axillary artery then becomes the brachial artery, which supplies blood to the region near the head of the humerus.
Step-by-step explanation:
Once the subclavian artery crosses under the clavicle and over the 1st rib, it is now named the axillary artery. The axillary artery continues into the brachium and becomes the brachial artery. This artery supplies blood to the region near the head of the humerus and the majority of the vessel continues into the brachium.