Re: yolk sac
From: Daniel Margulies (danymarg@movi.com.ar)
Sun May 27 14:34:33 2001
Dear Dr. Udayakumar
I think that all of us will like that presentation
Yhanks you in advance
-----Mensaje original-----
De: udaya kumar <udaya@md2.vsnl.net.in>
Para: Multiple recipients of list ULTRASOUND
<ultrasound@mail.medispecialty.com>
Fecha: Viernes, 25 de Mayo de 2001 10:20 p.m.
Asunto: Re: yolk sac
>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.
>
