What is the primary blood supply for the spinal cord?

The primary blood supply for the spinal cord is indeed provided by one anterior spinal artery and two posterior spinal arteries. The anterior spinal artery runs along the anterior median fissure of the spinal cord and supplies blood to the anterior two-thirds of the spinal cord, which includes the corticospinal tracts that are crucial for motor function. The two posterior spinal arteries supply the posterior one-third of the spinal cord, which is important for sensory function.

While segmental arteries from the aorta and radicular arteries do play roles in supplying blood to different parts of the spinal cord, they do not serve as the primary blood supply. The segmental arteries provide additional support and contribute to the overall vascular network of the spinal cord, but the anterior and posterior spinal arteries are the most significant in terms of maintaining the spinal cord's blood flow. The anterior spinal artery’s role is particularly critical because of its supply to key tracts involved in motor commands, making it integral to the function of the spinal cord during activities such as movement and reflexes.