Final answer:
The scapular anastomoses allow for reverse flow in the arterial system when the subclavian or axillary arteries are ligated, ensuring that affected areas still receive blood.
Step-by-step explanation:
When considering scapular anastomoses in the event of ligation of the subclavian and axillary arteries, the arterial anastomoses enable reverse flow to maintain blood supply to critical areas. The subclavian artery is crucial as it supplies blood to the arms, chest, shoulders, back, and central nervous system. It branches into the internal thoracic artery, vertebral artery, and thyrocervical artery. The vertebral artery, notable for its passage through the cervical vertebrae and foramen magnum, supplies blood to the brain and spinal cord, forming an anastomosis with the paired vertebral arteries to create the basilar artery. The circulatory system has various collateral pathways to ensure that blood can still reach affected areas even if the primary route is obstructed, as seen with the scapular anastomoses.