| abdominal aortic plexus | <anatomy, neurology> An autonomic plexus surrounding the abdominal aorta, directly continuous with the thoracic aortic plexus above and continued inferior to the bifurcation of the aorta as the superior hypogastric plexus. Synonym: plexus aorticus abdominalis. (05 Mar 2000) |
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| acute aortic dissection | <cardiology> A condition in which a weakened portion of the thoracic aorta begins to tear along the longitudinal axis of the vessel. Symptoms include sudden, severe chest pain that may radiate to the back accompanied by nausea, sweating and difficulty breathing. A common risk factor for this event is atherosclerotic vascular disease and-or hypertension. Advanced cases of syphilis (syphilitic aortitis) can also result in acute thoracic dissection as a complication of infection with Treponema pallidum. (27 Sep 1997) |
| aortic | Relating to the aorta or the aortic orifice of the left ventricle of the heart. Synonym: aortal. (05 Mar 2000) |
| aortic aneurysm | Dangeous ballooning of the aorta (the main artery leaving the heart) which is caused by disease in the artery's wall. (09 Oct 1997) |
| aortic aneurysm, abdominal | An aneurysm in that part of the aorta continuing from the thoracic region and giving rise to the inferior phrenic, lumbar, median sacral, mesenteric, renal, and ovarian or testicular arteries. (12 Dec 1998) |
| aortic aneurysm, thoracic | An aneurysm in the proximal portion of the descending aorta proceeding from the arch of the aorta and giving rise to the bronchial, oesophageal, pericardiac, and mediastinal branches. (12 Dec 1998) |
| aortic area | The region of the chest wall over the second right costal cartilage, where sounds produced at the aortic orifice are often best heard. (05 Mar 2000) |
| aortic atresia | Congenital absence of the normal valvular orifice into the aorta. (05 Mar 2000) |
| aortic bodies | Small clusters of chemoreceptive and supporting cells located near the aortic arch, the pulmonary arteries, and the coronary arteries. The aortic bodies sense pH, carbon dioxide, and oxygen concentrations in the blood and participate in the control of respiration. (12 Dec 1998) |
| aortic body tumour | Aortic body, carotid body, chemoreceptor, or glomus jugulare tumour; nonchromaffin paraganglioma; receptoma; a relatively rare, usually benign neoplasm originating in the chemoreceptor tissue of the carotid body, glomus jugulare, and aortic bodies; consisting histologically of rounded or ovoid hyperchromatic cells that tend to be grouped in an alveolus-like pattern within a scant to moderate amount of fibrous stroma and a few large thin-walled vascular channels. Compare: paraganglioma. Synonym: aortic body tumour, carotid body tumour, chemoreceptor tumour, glomus jugulare tumour, nonchromaffin paraganglioma. Origin: chemo-+ G. Dektes, receiver, fr. Dechomai, to receive, + -oma, tumour (05 Mar 2000) |
| aortic bulb | The dilated first part of the aorta containing the aortic semilunar valves and the aortic sinuses. Synonym: bulbus aortae, arterial bulb. (05 Mar 2000) |
| aortic coarctation | <radiology> most frequent cause of PVH and congestive heart failure in 2nd and 3rd weeks of life associated with, bicuspid aortic valve (50-80%), calcific aortic stenosis (due to bicuspid valve), patent ductus arteriosus or VSD (in most) see also: abdominal aortic coarctation (12 Dec 1998) |
| aortic curtain | An intertrigonal sheet of fibrous tissue between the aortic annulus and the anterior leaflet of the mitral valve. (05 Mar 2000) |
| aortic dissection | A pathologic process, characterised by splitting of the media layer of the aorta, which leads to formation of a dissecting aneurysm. Classified according to location as follows: type I involves the ascending aorta, transverse arch, and distal aorta; type II is confined to the ascending aorta; type III extends distally in the descending aorta. (05 Mar 2000) |
| aortic dissection: aetiology | <radiology> Usually degenerative, due to aging, increased risk: hypertension, bicuspic aortic valve, aortic coarctation, pregnancy, connective tissue disorder (Marfan, Ehlers-Danlos), skeletal abnormalities (scoliosis, pectus), mycotic aneurysm, Takayasu (giant cell) arteritis, aortic laceration see also: classification (12 Dec 1998) |