Feb28 M1-Embryology Hindgut and Anomalies Flashcards
what holds whole primitive gut during physiological herniation
sup and inf retention bands
SMA comes from what in the embryo and goes where
vitelline arteries (split in groups that also form celiac trunk and IMA) SMA goes to ANTIMESENTERIC side
phgy herniation before 90 degree counterclockwise rotation: which part of midgut is thicker and why
distal is thicker bc colon is differentiating + SI increasing in size a lot (so SI not thickening much)
where SMA branches to colon are
in mesocolon
specific differentiation happening in colon during phgy herniation
cecum differentiating and appendix forming
critical events during the 90d counterclockwise rot of midgut
- duodenum thrown on back wall by lig of Treitz
- yolk sac getting smaller
where is yolk sac attached on the gut (SMA going to yolk sac) initially and as it reduces
near ileocecal junction
2nd step of midgut rotation
180 degrees counterclockwise. now thicker colon on top and bit more to the back
colon and cecum position after midgut total 270 rotation
RUQ. cecum under the liver. appendix in RUQ too
what indicates if midgut rotation went well
position of SMA and SMV (SMV has to be on right of SMA)
importance of yolk sac closure
yolk sac and vitelline duct become small and close. otherwise: Meckel’s diverticulum near ileocecal junction
end position of SMA and SMV after rotation
over D3
possible cause and consequence of malrotation of the gut
possible cause: not C shaped duodenum
possible consequence: left sided colon (all on left side)
consequences of malrotation of gut
- left sided colon (and right sided intestines)
- fixation anomalies
- abnormal appendix location
causes of CLOCKWISE 180 deg rotation of midgut
- duodenum not fixed
- long lig of Treitz
- lax duodenum
