| arnold-chiari malformation | <radiology> Chiari I herniation of medulla and cerebellar tonsils, 4th ventricle in normal position, Chiari II herniation of medulla, tonsils, vermis, 4th ventricle at foramen magnum, myelomeningocele, aqueductal stenosis most likely to be hydrocephalus, Chiari III further herniation, 4th ventricle below foramen magnum, encephalocele or myelomeningocele associated with: agenesis of corpus callosum, syrinx (12 Dec 1998) |
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| arteriovenous malformation | <anatomy, embryology> A tangled collection of abnormal blood vessels where there is an abnormal communication between the arterial and venous systems. The afferents flow directly into the venous efferents without the usual resistance of an intervening capillary bed. They are mostly congenital. If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. Common sites include; skin, liver, brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid haemorrhage). See: arteriovenous fistula, cerebral arteriovenous malformations. Synonym: haemangioma (20 Jun 2000) |
| A-V malformation | <anatomy, embryology> A tangled collection of abnormal blood vessels where there is an abnormal communication between the arterial and venous systems. The afferents flow directly into the venous efferents without the usual resistance of an intervening capillary bed. They are mostly congenital. If large enough, they may produce a shunt of sufficient magnitude to raise the cardiac output. Common sites include; skin, liver, brain, brainstem and spinal cord, where they may cause headaches, seizures or bleeding (subarachnoid haemorrhage). See: arteriovenous fistula, cerebral arteriovenous malformations. Synonym: haemangioma (20 Jun 2000) |
| malformation | <embryology> A morphologic defect resulting from an intrinsically abnormal developmental process. Origin: L. Malus = evil, formatio = a forming (18 Nov 1997) |
| cerebellomedullary malformation syndrome | <radiology> Chiari I herniation of medulla and cerebellar tonsils, 4th ventricle in normal position, Chiari II herniation of medulla, tonsils, vermis, 4th ventricle at foramen magnum, myelomeningocele, aqueductal stenosis most likely to be hydrocephalus, Chiari III further herniation, 4th ventricle below foramen magnum, encephalocele or myelomeningocele associated with: agenesis of corpus callosum, syrinx (12 Dec 1998) |
| congenital malformation | Abnormal formation of a structure evident at birth. (12 Dec 1998) |
| cystic adenomatoid malformation of lung | <radiology> Only true pulmonary cystic disease of newborn, three X-ray types: multicystic, walls of varying thickness, multicystic, one large dominant thin-walled cyst, solid, mediastinal shift common, cysts often contain foetal lung fluid, Treatment: surgery Cf: congenital lobar emphysema (12 Dec 1998) |
| cystic adenomatoid malformation of lung, congenital | A developmental anomaly that usually becomes apparent in the neonatal period with progressive respiratory distress. This malformation is a focal pulmonary dysplasia characterised by a multicystic mass of terminal bronchiolar structures. Ccam is classified into 3 separate types (I, II, III) depending on cyst size. (12 Dec 1998) |
| acute vascular occlusion | <cardiology, surgery> A serious condition that results from the sudden blockage of an artery, usually with a blood clot. (27 Sep 1997) |
| acute vascular purpura | <dermatology> This relatively rare disorder is characterised by skin purpura, joint pains, abdominal pain and renal disease (glomerulonephritis). Although Henoch-Schonlein purpura or anaphylactoid purpura, is thought to be a immune complex mediated disease, its exact cause is unknown. Its typical benign coarse can, however, include renal failure. (27 Sep 1997) |
| articular vascular circle | An anastomosis of vessels encircling a joint. See: articular vascular network. Synonym: circulus articularis vasculosus. (05 Mar 2000) |
| articular vascular network | A vascular rete in the neighborhood of a joint, where such arrangements are common, enabling a collateral circulation by which blood will be supplied distal to the joint regardless of compromises resulting from joint position. Synonym: circulus articularis vasculosus, rete vasculosum articulare, articular network. (05 Mar 2000) |
| articular vascular network of elbow | Vascular networks in the region of the elbow, composed of anastomoses between branches of the radial and middle collateral, superior and inferior ulnar collateral, radial recurrent, interosseous recurrent, and recurrent ulnar arteries. Synonym: rete articulare cubiti. (05 Mar 2000) |
| articular vascular network of knee | An arterial network over the front and sides of the knee, formed by branches of the descending genicular artery, of the five genicular arteries from the popliteal, of the anterior tibial recurrent, and of the fibular circumflex branch of the posterior tibial. Synonym: rete articulare genus. (05 Mar 2000) |
| atherosclerotic vascular disease | <cardiology> The progressive narrowing and hardening of the arteries over time. This is known to occur to some degree with aging, but other risk factors that accelerate this process have been identified. These factors include: high cholesterol, high blood pressure, smoking, diabetes and family history for atherosclerotic disease. (27 Sep 1997) |