| 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) |
| accessory placenta | An extra placenta separate from the main placenta. Also called a succenturiate or supernumerary placenta. (12 Dec 1998) |
| adherent placenta | A placenta that fails to separate cleanly from the uterus after delivery. (05 Mar 2000) |
| annular placenta | A placenta in the form of a band encircling the interior of the uterus. Synonym: zonary placenta. (05 Mar 2000) |
| battledore placenta | A placenta in which the umbilical cord is attached at the border; so-called because of the fancied resemblance to the racquet (racket) used in battledore, a precursor to badminton. (05 Mar 2000) |
| bidiscoidal placenta | A placenta with two separate disc-shaped portions attached to opposite walls of the uterus, normal for certain monkeys and shrews, and occasionally found in humans. (05 Mar 2000) |
| margination of placenta | See: placenta marginata. (05 Mar 2000) |
| maternal placenta | <anatomy> The part of the placenta derived from the uterine tissue. See: placenta. Synonym: maternal placenta, placenta uterina. (05 Mar 2000) |