amnion cavity: a tube-like insinking from the ventral plate of the embryo, extending cephalad.
amnion: the inner of the two membranes enveloping the embryo.
Both it and the stalk of the yolk-sack are enveloped by the amnion (am).
Only in the chancel were they protected by sheep's amnion stretched on frames.
The amnion in fact begins to pulsate slowly and rhythmically, and by its pulsation the embryo is rocked to and fro in the egg.
It adheres to the amnion and supplies it with blood-vessels (Bischoff).
The embryo thus enclosed in the egg finds its protection in the fact that it is encased in a fluid contained in the amnion.
Superficial to it is the amnion, and below it is the yolk sac.
In all the classes of amniotes these membranes (the amnion and the serolemma) develop in just the same fashion.
This second fold gives rise to the amnion, and is limited entirely to the somatopleure.
1660s, Modern Latin, from Greek amnion "membrane around a fetus," said to be originally "bowl in which the blood of victims was caught" [Liddell & Scott], which is variously said to be of unknown origin, from ame "bucket," or a diminutive of amnos "lamb."
amnion am·ni·on (ām'nē-ən, -ŏn')
n. am·ni·ons or am·ni·a (-nē-ə)
The thin, membranous sac filled with a serous fluid in which the embryo or fetus is enclosed and suspended in the uterus. Also called amniotic sac.