| neural tube defect | <neurology, paediatrics> Abnormal development during embryonic life of the neural tube producing congenital malformations of the nervous system due to closure failure of the neural tube. The structure gives rise to the central nervous system (the brain and spinal cord), and failure to close results in anencephaly (absence of the cranial vault and absence of most or all of the cerebral hemispheres of the brain) and spina bifida or meningomyelocele (open spina with exposure and protusion of the spinal cord). The risk of neuroal tube defects can be decreased by the mother taking folic acid during pregnancy. (04 Jul 1999) |
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| dorsal plate of neural tube | The thin layer of the embryonic neural tube connecting the alar plate's dorsally. Synonym: dorsal plate of neural tube. (05 Mar 2000) |
| dorsolateral plate of neural tube | The dorsal division of the lateral walls of the neural tube in the embryo; it gives rise to neurons relaying afferent impulses to higher centres; in the adult such neurons compose the sensory nuclei of the spinal cord and brainstem. Synonym: lamina alaris, alar plate of neural tube, dorsolateral plate of neural tube, lamina dorsalis, wing plate. (05 Mar 2000) |
| anterior basal segment | Anterior basal segment of inferior lobe of right and left lung; lies between middle lobe and diaphragm. Synonym: segmentum basale anterius. (05 Mar 2000) |
| anterior eye segment | That part of the eyeball anterior to the lens. (12 Dec 1998) |
| anterior inferior segment | Anterior inferior segment of kidney. Synonym: segmentum anterius inferius. (05 Mar 2000) |
| anterior ocular segment | That portion of the eye comprising the cornea, iris, lens, and their associated chambers and adnexa. (05 Mar 2000) |
| anterior segment | A delimited part or section of an organ or other structure which lies in front of or ventral to the other similar parts or sections. 1) segmentum anterius (hepar); the anterior segment of the right lobe of the liver. 2) segmentum anterius (pulmo dexter et sinister); [S 3]; the anterior segment of the superior lobe of the right and left lungs. 3) anterior segment of the eye; the intraocular segment of the eyeball occupied by the aqueous which lies in front of, and is separated from the vitreous-filled posterior segment by, the lens and zonule; it is subdivided by the iris into anterior and posterior chambers. Synonym: segmentum anterius. (05 Mar 2000) |
| anterior superior segment | Anterior superior segment of kidney. Synonym: segmentum anterius superius. (05 Mar 2000) |
| apical segment | Apical segment of the superior lobe of the right lung, apical segment of the inferior lobe of the right and left lungs. Synonym: segmentum superius. Synonym: segmentum superius, segmentum apicale, superior segment. (05 Mar 2000) |
| apicoposterior segment | Apicoposterior segment of superior lobe of left lung, composed of two segments and wedged between the anterior segment of the upper lobe and the oblique fissure. Synonym: segmentum apicoposterius. (05 Mar 2000) |
| artery of anterior inferior segment of kidney | Origin, anterior branch of renal. See: segmental arteries of kidney. Synonym: arteria segmenti anterioris inferioris renis, artery of anterior {inferior segment of kidney}. (05 Mar 2000) |
| artery of anterior superior segment of kidney | Origin, anterior branch of renal. See: segmental arteries of kidney. Synonym: arteria segmenti anterioris superioris renis, artery of anterior {superior segment of kidney}. (05 Mar 2000) |
| artery of inferior segment of kidney | Origin, anterior branch of renal. See: segmental arteries of kidney. Synonym: arteria segmenti inferioris renis, artery of inferior segment of kidney. (05 Mar 2000) |
| artery of posterior segment of kidney | Origin, continuation of the posterior branch of renal. See: segmental arteries of kidney. Synonym: arteria segmenti posterioris renis, artery of posterior segment of kidney. (05 Mar 2000) |