Blood Supply – Spinal Cord and Brachial Plexus

Spinal Cord

For tissue to survive, it needs a constant supply of oxygenated blood. All oxygenated blood that circulates through the body originally passes through the aorta in the heart; and is then sent through different arteries depending on its final location. For the spinal cord, there are three primary arteries that blood travels through: one anteriorly, and two posteriorly. These arteries, as shown below, are identified by their location in respect to the spinal cord.

The anterior spinal artery is the result of an anastomosis originating from the subclavian artery, proximal to the brachial artery, on each side of the neck and travels in the anterior median fissure. This anastomosis leads to the blood supply for the entirety of the anterior component of the spinal cord. There are also two posterior arteries that originate in the cranial cavity, and descend the entire length of the spinal cord.

The last contributing factor to the spinal cord’s blood supply comes from the medullary arteries, and primarily the artery of Adamkiewicz (teachmeanatomy.com) which can supply the inferior 2/3 of the spinal cord. The artery of Adamkiewicz is responsible for the blood supply to the lower thoracic, lumbar, and sacral regions of the spinal cord. The most common mechanism for injury to this artery occurs in descending aortic repairs.

The Brachial Plexus

            The brachial plexus (BP) creates a unique situation because the innervation pathways do not run directly beside their arterial supply. The brachial plexus receives its blood supply from multiple locations, and these locations are dependent upon which region of the BP is in question.

The BP innervation system is broken into roots, trunks, divisions, cords, and branches. The roots and trunks draw oxygenated blood from the anterior and posterior spinal branches stemming off the vertebral artery (emedicine.medscape.com). The more distal divisions and cords, however, get their blood supply from more specific arteries defined by the regions of the BP that they supply.

 

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