Vascular myelopathy later in this article. However, TIAs can result from emboli in calcific aortic disease and aortic coarctation. Spinal arteriovenous malformations (AVMs, or angiomatous malformations) are congenital (from birth) abnormalities of blood vessels. Arteries that directly communicate with veins bypass the capillary network (which has not yet developed) and thus creates a shunt. AVMs appear as a mass of convoluted, dilated vessels. In regards to the spinal cord, they are usually located in the thoracolumbar region (between the thoracic and lumbar regions, 60% of the time), as opposed to the upper thoracic (20%) and cervical regions (approximately 15%). Cervical malformations arise
Blood air to all of the cells of the body, and venous blood carries carbon dioxide, a waste product of metabolism by cells, to the lungs to be exhaled. However, one exception includes pulmonary arteries, which contain the most deoxygenated blood in the body, while the pulmonary veins contain oxygenated blood. Additional return flow may be generated by the movement of skeletal muscles, which can compress veins and push blood through the valves in veins toward the right atrium. The blood circulation was famously described by William Harvey in 1628. In vertebrates, the various cells of blood are made in the