Re: yolk sac
From: Terry J DuBose (tjdubose@juno.com)
Sat May 26 06:40:44 2001
Dr. Udayakumar, thank you for offering to post your powerpoint
presentation on Coelocentesis. It will be a welcome addition to our
growing educational materials. Please post it.
Thanks for your input and support.
--
Terry J DuBose
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On Fri, 25 May 2001 20:22:17 -0500 udaya kumar <udaya@md2.vsnl.net.in>
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writes:
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> Dear Terry,
> The extraamniotic space has a fluid that can been aspirated (
> Coelocentesis) .
> Using FISH probes it appears that Karyotyping is possible at 6weeks
> gestation.
> Made a powerpoint presentation on Coelocentesis in a recent
> conference. Will
> post it to you if you want it.
> .Udayakumar
>
> DuboseTerryJ@uams.edu wrote:
>
> > According to Moore & Persaud, DEVELOPING HUMAN: Clinically
> Oriented
> > Embryology, W. B. Saunders, 1993 p. 40-46 & 70-80; what we see
> > sonographically is actually the "secondary yolk sac". The
> "primary yolk
> > sac" develops earlier (during 3rd LMP week, i.e. 9 days after
> conception)
> > and is too small to visualize sonographically. The secondary yolk
> develops
> > around conceptual day 13 (start of 4 LMP week).
> >
> > You are correct in that the yolk is related to the formation of
> the fetal
> > gut. Moore & Persaud has a great graphic representation of this
> process on
> > page 71. The amnion forms around the embryo and separates or
> "squeezes" the
> > yolk sac from the midgut and intraembryonic coelom at about 26-28
> post
> > conception.
> >
> > An interesting bit of trivia... I had always wondered what the
> "choronic
> > cavity" outside the amnionic sac contained... I was sure that it
> was not a
> > vacuuume, but could not find any reference other than "cavity".
> Finally
> > during research for FETAL SONOGRAPHY, I found the answer in:
> Benirschke K;
> > "NORMAL DEVELOPMENT", Chapter 4; in Creasy RK and Resnik R,
> Editors;
> > MATERNAL-FETAL MEDICINE: Principles and Practice, 2nd Edition; W.
> B.
> > Saunders Company, 1989; p. 117.
> > "As the pregnancy progresses the thin amniotic membrane enlarges
> and will
> > contain the embryo, the yolk sac will remain outside the amnion.
> See Figure
> > 16-12C. The amniotic sac with it's embryo, and the yolk sac are
> all found
> > within the so called "gestational sac". This gestational sac is
> actually the
> > chorionic cavity. The chorionic space around the amniotic sac is
> filled
> > "...by a gel that liquefies upon touching, the magma reticulare."
> This magma
> > reticulare has a slightly echogenic appearance when compared to
> the very
> > clear amniotic fluid; see Figure 16-12C. The magma reticulare is
> also called
> > the "chorioamniotic accumulation" and is a normal finding before
> the amnion
> > and chorion fuse." See: DuBose, FETAL SONOGRAPHY, W. B. Saunders
> Co., 1996,
> > p. 370.
> >
> > Terry J. DuBose, M.S., RDMS, Assistant Professor
> > Director, Diagnostic Medical Sonography Program
> > CHRP, University of Arkansas for Medical Sciences
> > Little Rock, Arkansas, USA
> > 501-686-6510
> > http://www.io.com/~dubose/ <http://www.io.com/~dubose/>
> > http://www.uams.edu/CHRP/dmshome.htm
> <http://www.uams.edu/CHRP/dmshome.htm>
> >
> > http://www.obgyn.net/us/panel/panel.htm
> > <http://www.obgyn.net/us/panel/panel.htm>
> >
> > -----Original Message-----
> > From: Dr. N. A. Mohile [mailto:namohile@satyam.net.in]
> > Sent: Friday, May 25, 2001 10:42 AM
> > To: Multiple recipients of list ULTRASOUND
> > Subject: yolk sac
> >
> > The round structure seen within the gestation sac by 5 weeks and
> called yolk
> > sac is visible even at 12 weeks outside the amniotic
> sac.Embryologically
> > yolk sac forms the gut.Is this structure really yolk sac?
> > -Nila.
>
