Normal anatomy pt2 Flashcards
by the end of the third week of the LMP, the ______ begins to implant into the decidulized endometrium
blastocyst
during the implantation process, as the ______ tissue invades the endometrium, occasional vaginal bleeding can occur. This is perceived by the patient as spotting
trophoblastic
what are the sonographic findings of the implantation phase?
there are three distinct layers of decidulized endometrium that can be observed (Decidua basalis, decidua capsularis, and ducidua parietalis)
______ develops where the blastocyst implants, it is the maternal contribution to the placenta
decidua basalis
______ closes over and surrounds the blastocyst
decidua capsularis
______or ______ is the uninvolved endometrial tissue that is hyped up because of hormones
decidua perietalis or decidua vera
the placenta is derived from both the ______ and ______ tissue
maternal and fetal
what are the maternal components derived from?
decidua basalis
what are the fetal components derived from?
trophoblastic tissue
the trophoblast develops into ______ which come in contract with the ducidua basalis to preliferate and become the ______ or the fetal part of the placenta
chorionic villi, chorion frondosum
what forms from the inner mass and becomes a cavity to fill the chorionic or uterine cavity?
the amnion
the ______ and _______ begin to fuse by the middle of the first trimester and fusion is complete by ______ weeks
amnion and chorion, 16 weeks- it is perfectly normal to see sonographic separation of the two membranes before 16 weeks
what is intra decidual sac sign and when is it seen?
seen when serum beta hCG level is 1000 and mlu/ml or greater, it is a cystic space within the uterine cavity
what is the double decidual sac sign?
inner anechoic amnionic sac, surrounding echogenic decidula capsularis, surrounding anechoic uterine cavity, and outer echogenic decidula vera
how do you measure the mean sac diameter?
length+height+width divided by three
the ______ is the first structure seen within the gestational sac
yolk sac
where is the yolk sac located?
between the chorion and the amniotic cavity
what is the function of the yolk sac?
to make fetal blood until the fetus can take over
how do you measure the yolk sac?
from inner to inner
what do you use when you date a pregnancy?
only the most advanced structure!, if you only have the gestational sac use that, but if a fetus is developed used the crown rump length only
do you ever use both the gestational sac measurement and the crown rump measurement?
No! only the advanced most part of the pregnancy
embryo grows at a rate of ______ per day
1mm
with ______ imaging the embryonic anatomy can be seen earlier than with transabdominal
transvaginal
Always used transvaginal sonography to evaluate the early pregnancy, but what is the only time you would not?
in the case of patients adamant refusal even after she has been explained the benefits
______ is an anechoic structure seen in the posterior part of the fetal brain from 8-11 weeks
rhombencephalon
what does rhombencephalon look like?
a cyst in the brain
do you ever measure the rhombencephalon?
no, it is normal development of the central nervous system and it must not be confused with an abnormality
the ______ herniates into the base of the umbilical cord at 9 weeks and returns to the abdominal cavity at 12 weeks
midgut- it is a normal physiologic function and should never be confused for Omphalocele or Gastroschesis
