Which arteries form the primary collateral pathway around the shoulder that can maintain blood flow to the arm if the axillary artery is occluded?

The correct answer is C. Suprascapular and circumflex scapular.

• The axillary artery is divided into three parts. An injury between the second and third parts means that blood flow to the arm distal to the injury would be compromised without a collateral pathway.
• The scapular anastomosis is a crucial collateral circulation around the shoulder joint that can maintain blood flow to the arm if the axillary artery is occluded. This anastomosis involves several arteries.
• The suprascapular artery originates from the thyrocervical trunk (a branch of the subclavian artery).
• The circumflex scapular artery is a branch of the subscapular artery, which itself is a major branch of the third part of the axillary artery.
• These two arteries, along with the dorsal scapular artery, form a network around the scapula, allowing blood from the subclavian artery to bypass an obstruction in the axillary artery and reach the distal part of the axillary artery and subsequently the brachial artery. This rich collateral pathway is why the surgeon had time to repair the wound.