The amniotic sac
is the sac in which the fetus
Some sources consider it to be equivalent to the amnion..
When in the light, the amniotic sac is shiny and very smooth, but too tough to pierce through.
An artificial rupture of membranes (ARM
), also known as an amniotomy
, may be performed by a midwife
. This is usually performed using an amnihook and is intended to induce or accelerate labour.
The presence of the amnion identifies humans and other mammals
, along with reptiles
but not amphibians
is the watery liquid surrounding and cushioning a growing fetus within the amnion. It allows the fetus to move freely without the walls of the uterus
being too tight against its body. Buoyancy is also provided.