Which statement about the subclavian arteries is correct?

• A. They supply the hind limbs.
• B. They do not give off branches in the thorax.
• C. They supply the forelimbs but do not form axillary arteries.
• D. They supply the forelimbs and curve around the cranial edge of the first rib to form axillary arteries.

Answer: (D)

The key idea is how the subclavian arteries relate to the forelimbs and where the transition to the axillary arteries occurs. In mammals, the subclavian arteries give branches that supply thoracic and neck regions, and as they pass the first rib, they curve around its cranial edge and continue as the axillary arteries to furnish the forelimbs. This description—supplying the forelimbs and forming axillary arteries at the edge of the first rib—matches the actual anatomy, making it the correct statement.

Hind limbs aren’t supplied by the subclavian arteries; they receive blood from arteries of the pelvic limb. The subclavian arteries do give off branches within the thorax (for example, vessels that go to thoracic structures), so saying they don’t branch there is inaccurate. And the subclavian arteries do form axillary arteries after crossing the first rib, so saying they supply forelimbs but do not form axillary arteries is also incorrect.