aneurysm /an·eu·rysm/ (an´u-rizm) a sac formed by localized dilatation of the wall of an artery, a vein, or the heart.aneurys´mal
berry aneurysm
berry aneurysm
aortic aneurysm aneurysm of the aorta.
arteriosclerotic aneurysm an aneurysm arising in a large artery, usually the abdominal aorta, as a result of weakening of the wall in severe atherosclerosis.
arteriovenous aneurysm abnormal communication between an artery and a vein in which the blood flows directly into a neighboring vein or is carried into the vein by a connecting sac.
atherosclerotic aneurysm arteriosclerotic a.
berry aneurysm a small saccular aneurysm of a cerebral artery, usually at the junction of vessels in the circle of Willis, having a narrow opening into the artery.
compound aneurysm one in which some of the layers of the wall of the vessel are ruptured and some merely dilated.
dissecting aneurysm one resulting from hemorrhage that causes longitudinal splitting of the arterial wall, producing a tear in the intima and establishing communication with the lumen; it usually affects the aorta (aortic dissection).
false aneurysm
1. one in which the entire wall is injured and the blood is retained in the surrounding tissues; a sac communicating with the artery (or heart) is eventually formed.
2. pseudoaneurysm.
infected aneurysm one produced by growth of microorganisms (bacteria or fungi) in the vessel wall, or infection arising within a preexisting arteriosclerotic aneurysm.
mycotic aneurysm an infected aneurysm caused by fungi.
racemose aneurysm dilatation and tortuous lengthening of the blood vessels.
saccular aneurysm , sacculated aneurysm a distended sac affecting only part of the arterial circumference.
varicose aneurysm one in which an intervening sac connects the artery with contiguous veins.
ber·ry aneurysm (b r  )n. A small saccular aneurysm of a cerebral artery that resembles a berry. |
berry aneurysm
Etymology: ME, berye + Gk, aneurysma, widening
a small, saccular dilation of the wall of a cerebral artery. It occurs most frequently at the junctures of vessels in the circle of Willis. A berry aneurysm may be the result of a congenital developmental defect and may rupture without warning, causing intracranial hemorrhage. Smoking and hypertension increase the likelihood of rupture.
aneurysm
a sac formed by the localized dilatation of the wall of an artery, vein or the heart.
aortic aneurysm
see aortic aneurysm.
arteriovenous aneurysm
an abnormal communication between an artery and a vein in which the blood flows directly into a neighboring vein or is carried into the vein by a connecting sac.
atherosclerotic aneurysm
one arising as a result of weakening of the tunica media in severe atherosclerosis.
bacterial aneurysm
an infected aneurysm caused by bacteria.
berry aneurysm
a small saccular aneurysm of a cerebral artery, usually at the junction of vessels in the circle of Willis; such aneurysms frequently rupture, causing subarachnoid hemorrhage. Called also brain aneurysm.
cardiac aneurysm
thinning and dilatation of a portion of the wall of the left ventricle, usually a consequence of myocardial infarction.
cirsoid aneurysm
dilatation and tortuous lengthening of part of an artery.
compound aneurysm
one in which some of the layers of the wall of the vessel are ruptured and some merely dilated. Called also mixed aneurysm.
congenital aneurysm
observed sporadically in the aorta and pulmonary artery.
dissecting aneurysm
one resulting from hemorrhage that causes lengthwise splitting of the arterial wall, producing a tear in the inner wall (intima) and establishing communication with the lumen of the vessel; it usually affects the thoracic aorta. Seen most commonly in horses and caused by larvae of Strongylus vulgaris. See strongylosis. A specific disease of turkeys.
fusiform aneurysm
a spindle-shaped aneurysm.
infected aneurysm
one produced by growth of microorganisms (bacteria or fungi) in the vessel wall, or infection arising within a pre-existing arteriosclerotic aneurysm.
inherited aortic aneurysm
causes a high mortality rate in the affected cattle breed. The defect is in the abdominal aorta.
lung aneurysm
may result from the lodgement of pulmonary emboli; rupture and pulmonary hemorrhage are potential sequelae.
mixed aneurysm
compound aneurysm.
mycotic aneurysm
an infected aneurysm caused by fungi.
pseudoaneurysm
false aneurysm.
racemose aneurysm
cirsoid aneurysm.
sacculated aneurysm
a saclike aneurysm.
varicose aneurysm
one formed by rupture of an aneurysm into a vein. See also aneurysmal varix.
venous aneurysm
see venous dilatation.
verminous aneurysm
see strongylosis.
berry aneurysm
Neurology A 0.2-0.5 cm saccular dilation of arteries at the base of the brain, at or near the circle of Willis–95% of BAs or at the vertebrobasilar arteries–5%, due to a developmental or congenital weakness in the
medial muscle layer of the cerebral arteries; 30% of BAs are multiple, located at bifurcations, often anterior and appear in 1-2% of all autopsies; most BAs rupture at > 1 cm in diameter. See Circle of Willis.
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