The ornamental design of a shirtpanel, substantially as shown and described.
FIG. 1 is a front view of a shirt panel embodying the design of the present invention; and,
FIG. 2 is a back view of the shirt panel shown in FIG. 1.
The crosshatched pattern, although shown intermittently, is meant to represent fabric, and is understood to be distributed uniformly over the surfaces of the claimed design upon which it resides. The shirt panel when viewed from a side view, is flat. The long dash-short dash lines in the figures represent both the bounds of the claimed design and form a part of the claimed design. The dashed lines of the underarm portion represent stitching and form part of the claimed design.