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 pressure occurs along the small arteries and arterioles. Gravity affects blood pressure via hydrostatic forces (e.g., during standing), and valves in veins, breathing, and pumping from contraction of skeletal muscles also influence blood pressure in veins. Most influences on blood pressure can be understood in terms of their effect on cardiac output and resistance (the determinants of mean arterial pressure). Some factors are: In practice, each individual's autonomic nervous system and other systems regulating blood pressure respond to and regulate all these factors so that, although the above issues are important, they rarely act in isolation and the actual arterial pressure