allantoic sac


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al·lan·to·ic sac

the dilated distal portion of the allantois; it forms part of the placenta in many mammals.

allantoic sac

The expanded end of the allantois, well developed in birds and reptiles.
See also: sac
References in periodicals archive ?
The allantoic sac should either be obviously visible now, or show evidence that it's been there and has already ruptured.
On the following ultrasound evaluations, between 25 and 60 days of pregnancy, the developmental pattern of the conceptus, including allantoic sac development, yolk sac regression and umbilical cord formation, was similar to that described for mated or inseminated pregnant mares (GINTHER, 1992; 1998), jennies (MEIRA et al., 1998) and mule embryos (PAOLUCCI et al., 2012).
Excessive accumulation of fluid either amniotic or allantoic sac referred as hydramnios or hydrallantois, respectively (Noakes, 2009).