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.
For the thoracic aorta, a diameter greater than 3.5 cm is generally considered dilated, whereas greater than 4.5 cm would be considered aneurysmal. Aneurysms may affect one or more segments of the thoracic aorta, including the ascending aorta, the arch, and the descending thoracic aorta.As many as 25% of patients with TAA also have an abdominal aortic aneurysm.neurysms may affect one or more segments of the thoracic aorta, including the ascending aorta, the arch, and the descending thoracic aorta. As many as 25% of patients with TAA also have an abdominal aortic aneurysm.