The ornamental design for a dispensing portstructure for flexible storage containers for medical use, as shown and described.
FIG. 1 is a perspective view of the dispensing port structure for flexible storage containers for medical use;
FIG. 2 is a front view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a side view thereof, the opposite side view being the same.
The flanges shown in broken lines in FIGS. 1 through 5, and the internal ribs and the internal surface shown in broken lines in FIG. 4 form no part of the claimed design.