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n. pl. ve·lam·i·na (-lăm′ə-nə)
1. Anatomy A membranous covering or partition; velum.
2. Botany A spongy layer of dead cells that covers the aerial roots of most orchids and certain other plants and may serve to absorb atmospheric moisture.

[Latin vēlāmen, covering, from vēlāre, to cover, from vēlum, a covering.]

vel′a·men′tous (vĕl′ə-mĕn′təs) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


n, pl -lamina (-ˈlæmɪnə)
1. (Botany) the thick layer of dead cells that covers the aerial roots of certain orchids and aroids and absorbs moisture from the surroundings
2. (Zoology) anatomy another word for velum
3. (Anatomy) anatomy another word for velum
4. (Botany) anatomy another word for velum
[C19: from Latin: a veil, from vēlāre to cover]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(vəˈleɪ mɪn)

n., pl. -lam•i•na (-ˈlæm ə nə)
1. Anat. a membranous covering; velum.
2. a corky, water-absorbent covering on the aerial roots of certain orchids.
[1880–85; < Latin vēlāmen=vēlā(re) to cover + -men n. suffix of result]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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These cord abnormalities include velamentous insertion, thin cord, kinking, hypercoiling, and entanglement.
The umbilical cord is inserted in most cases in this part of the placenta in a slightly eccentric position, but there are other types of insertion such as marginal cord insertion, where the cord is attached to the side, or velamentous cord insertion, where the umbilical vessels are separated in the membranes at a certain distance from the placental margin, where they arrive surrounded only by a fold in the amnion.
They include morphologic anomalies of the umbilical cord (both in length and in thickness), true knots, cord prolapse, traction or torsion, velamentous insertion of the cord, vessel wall abnormalities, umbilical cord cysts, abdominal trauma in pregnancy, postterm pregnancy, infections (chorioamnionitis and funisitis), deficiency of Wharton's jelly, congenital defects, and many more remain unexplained [13].
Prevalence, risk factors and outcomes of velamentous and marginal cord insertions: a population-based study of 634,741 pregnancies.
The patterns of insertion like central, marginal, velamentous, etc.
The following gross placental features were considered abnormal: placental weight < 5th percentile for gestational age [20], single umbilical artery, marginal or velamentous cord insertion, bilobed or succenturiate placenta, and circummarginate or circumvallate placenta.
Results: Detection rates of marginal umbilical cord entry abnormity and velamentous umbilical cord entry abnormity by means of CDUS at second trimester were 94.1% and 93.8% respecdtively much higher than 80.0% and 68.8% which were those of third trimester.
On the other hand insertion anomalies like velamentous insertions, nuchal umbilical cords and knots are relatively frequent findings and not necessarily associated with fetal death4.
In practice, we see a variety of surface shapes and cord insertion sites, with common variations such as bi- or multi-lobate shapes, or otherwise irregular shapes and cord insertions that are eccentric, marginal, or velamentous. Interestingly, many irregularly shaped placentas display symmetry and have regular, defined geometrical patterns, like snowflakes.
Placental ratio and risk of velamentous umbilical cord insertion are increased in women with placenta previa.
Baby A had a velamentous cord insertion, and baby B had a succenturiate lobe and a TUCK.