12 Key and Core Catalog With a mechanical key system, the level of security is determined by masterkey control. A masterkey system enables facilities of any size to manage the building by defining access by person and by area in increasing levels of complexity. Since BEST invented the standard for masterkey systems, there is no
When they occur in the upper part of the aorta, they are called thoracic aortic aneurysms. Aneurysms can occur anywhere in the thoracic aorta, including the ascending aorta near the heart, the aortic arch in the curve of the thoracic aorta and the descending aorta in the lower part of the thoracic aorta.
A thoracic aortic aneurysm, also called TAA, is a bulging, weakened area in the wall of the aorta (the largest artery in the body), resulting in an abnormal widening or ballooning greater than 50 percent of the vessel's normal diameter (width).horacic aneurysms do not occur as often as abdominal aneurysms. The descending thoracic aorta is the most common location of a thoracic aneurysm, followed by the ascending segment, then the arch. The location of an aneurysm is distinctly connected with the cause, course, and treatment of a thoracic aneurysm.