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congenital absence of the cranial vault, with the cerebral hemispheres completely missing or reduced to small masses. adj., adj anencephal´ic.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
Congenital absence of the calvaria and most of the brain, usually the forebrain and midbrain.
[mero- + G. an- priv. + enkephalos, brain]
Farlex Partner Medical Dictionary © Farlex 2012
n. pl. anencepha·lies
Congenital absence of most of the brain and spinal cord.
an′en·ce·phal′ic (-sə-făl′ĭk) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
anencephalyA lethal malformation consisting of congenital partial or complete absence of the cranial vault accompanied by absence of overlying tissues, including the brain and cerebral hemispheres, skull and scalp. Most anencephalics die within the first week, and are of use as potential organ donors; ethical dilemmas inherent in such use of humans has made this a contentious issue.
Anencephaly develops in the first month of gestation and affects 0.14–0.7/1000 live births. The primary defect is failure of cranial neurulation, the embryologic process separating the forebrain precursors from the amniotic fluid; since neural tissue is exposed, cerebral tissue is haemorrhagic, fibrotic, and gliotic without functional cortex.
Usually idiopathic, possibly multifactorial or polygenic in origin. The risk of neural tube defects, including anencephaly, can be decreased by an adequate maternal ingestion of folic acid during pregnancy.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
anencephalyNeonatology A lethal malformation consisting of congenital partial or complete absence of the cranial vault accompanied by absence of overlying tissues, including the brain and cerebral hemispheres, skull and scalp; anencephaly develops in the 1st month of gestation and affects 0.14-0.7/1000 live births; the 1º abnormality is failure of cranial neurulation, the embryologic process separating the forebrain precursors from the amniotic fluid; since neural tissue is exposed, cerebral tissue is hemorrhagic, fibrotic, gliotic without functional cortex Etiology Usually idiopathic, possibly multifactorial or polygenic in origin. See Uniform Determination of Death Act.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
Congenital defective development of the brain in which the brain and cranium are present in rudimentary form.
[meros + G. an-, priv. + enkephalos, brain]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
anencephalyAbsence of the greater part of the brain and of the bones (ACRANIA) at the rear of the skull. Anencephaly is a defect of development arising from a severe NEURAL TUBE DEFECT early in the development of the embryo and is incompatible with life. Anencephalic babies are born dead or die soon after birth. The term derives from the Greek an , not and encephalon , a brain. See ACEPHALUS.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
A hereditary defect resulting in the partial to complete absence of a brain and spinal cord. It is fatal.
Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.