ABSTRACT
In the first half of the embryonic period (4 to 6 weeks), a duodenal loop forms between the stomach and the embyonic midgut. At the same time, the latter is transformed into the midgut loop.
The Midgut Loop The embryonic midgut is triangular-shaped (Figure la). An increased rate of growth and intake of the dorsal border reshapes it into the midgut loop (Figure lb). Suspended by its dorsal mesentery, it has a narrow prox imal limb, and gives attachment to the yolk stalk at its convexity. Most of the distal limb is of wider caliber, and joins the hindgut (Figure lb).
