| AI | accidental injury; accidentally incurred; adiposity index; aggregation index; allergy and immunology... |
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| AS | acetylstrophanthidin; acidified serum; acoustic schwannoma; acoustic stimulation; active sarcoidosis... |
| AVO | aortic valve opening; aortic valve orifice; atrioventricular opening |
| SAR | scatter/air ratio; seasonal allergic rhinitis; sexual attitude reassessment; slowly adapting recepto... |
| SVAS | supravalvular aortic stenosis; supraventricular aortic stenosis |
| aortic lymphatic plexus | A plexus of lymph nodes and connecting vessels lying along the lower portion of the abdominal aorta. Synonym: plexus aorticus. (05 Mar 2000) |
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| aortic murmur | A murmur produced at the aortic orifice, either obstructive or regurgitant. (05 Mar 2000) |
| aortic nerve | <anatomy, nerve> A branch of the vagus which ends in the aortic arch and base of the heart; composed entirely of afferent fibres; its stimulation elicits a brainstem reflex which causes slowing of the heart, dilation of the peripheral vessels, and a fall in blood pressure. Synonym: Cyon's nerve, depressor nerve of Ludwig, Ludwig's nerve. (05 Mar 2000) |
| aortic notch | The notch in a sphygmographic tracing caused by rebound following closure of the aortic valves. (05 Mar 2000) |
| aortic occlusion | A blockage of the aorta somewhere along its path. This can result in irreversible damage to the organs which depend on aortic blood below the level of the blockage. See: atherosclerosis. (27 Sep 1997) |
| aortic opening | The opening in the diaphragm bounded by the two crura, the vertebral column, and the median arcuate ligament, through which pass the aorta and thoracic duct. Synonym: hiatus aorticus, aortic foramen, aortic opening. (05 Mar 2000) |
| aortic orifice | The opening from the left ventricle into the ascending aorta; it is guarded by the aortic valve. Synonym: ostium aortae, aortic ostium. (05 Mar 2000) |
| aortic ostium | The opening from the left ventricle into the ascending aorta; it is guarded by the aortic valve. Synonym: ostium aortae, aortic ostium. (05 Mar 2000) |
| aortic pseudo-coarctation | <radiology> Aortic kinking, rare congenital anomaly of aortic arch, long, redundant thoracic aorta, 3-sign, associated with aortic valve abnormalities (bicuspid valve, AI, AS), can develop aneurysms, no haemodynamic obstruction, no congenital heart disease Cf: coarctation (12 Dec 1998) |
| aortic-pulmonic window | The indentation of the left side of the mediastinum by the lung partially interposed between the aortic arch and the left pulmonary artery, seen on frontal radiographs of the chest. Synonym: aortic-pulmonic window. (05 Mar 2000) |
| aortic reflex | A fall in blood pressure due to peripheral vasodilation and cardiac inhibition by stimulations of terminations of a cardiac depressor nerve in the aortic arch and base of the heart. Synonym: aortic reflex, depressor reflex. (05 Mar 2000) |
| aortic regurgitation | A congenital or acquired heart valve abnormality that results in the abnormal back flow of blood in the aorta, through an incompetent aortic valve and into the left ventricle. Chronic aortic insufficiency leads to enlargement of the left ventricle and pulmonary congestion. If left uncorrected, congestive heart failure will result. Aortic valve replacement is eventually necessary in most cases of significant valvular incompetence. (27 Sep 1997) |
| aortic regurgitation: aetiology | <radiology> INTRINSIC VALVE DISEASE, congenital bicuspid valve, rheumatic endocarditis, bacterial endocarditis (perforation / prolapse of cusp), myxomatous valve associated with cystic medial necrosis, prosthetic valve: mechanical break, thrombosis, paravalvular leak PRIMARY DISEASE OF ASCENDING AORTA, dilatation of the aortic annulus, syphilitic aortitis, ankylosing spondylitis (5-10%), Reiter disease, rheumatoid arthritis, cystic medial necrosis: Marfan syndrome, laceration, decelerating trauma; hypertension see: aortic regurgitation (12 Dec 1998) |
| aortic rupture | Tearing of aortic tissue. It may be rupture of an aneurysm or it may be due to trauma. (12 Dec 1998) |
| aortic sac | In mammalian embryos, the endothelially lined dilation just distal to the truncus arteriosus; it is the primordial vascular channel from which the aortic arches arise and is homologous to the ventral aorta of gill-bearing vertebrates. (05 Mar 2000) |