Aneurysm - expansion of a lumen of the artery, caused by delicacy of a wall or its destruction. It can be single or plural. An aneurysm can be caused by congenital disease of a wall of a vessel, an atherosclerosis and an arteriosclerosis, a trauma, a syphilitic and mycotic lesion. Sometimes an aneurysm arises behind the narrowed site of a vessel. Under the form distinguish saccular and spindle-shaped to an aneurysm, false (the wall is presented by a fibrous tissue) and true (in an aneurysm the internal environment of a vessel is kept). At a simultaneous lesion of an artery and a vein can develop arteriovenous an aneurysm. In some cases there is an amotio of an internal environment of an artery, thus the blood stratifies walls of a vessel, forming a clump of a blood, - stratifying an aneurysm. False an aneurysm. After break of an artery more often a traumatic genesis in surrounding tissues the perivascular pulsing hematoma is formed. Signs: Tumescence, discoloration of a skin, pain and sensation of a pulsation. The prelum series of the located venous vessels is possible. False an aneurysm can become a source of a thromboembolism of the peripheric vessels, shown sudden weakening of pulse and signs of an ischemia of tissues.