We claim the ornamental design for a medical instrument handle, as shown and described.
FIG. 1 is left side view of our new design for a medical instrument handle.
FIG. 2 is right side view of our new design for a medical instrument handle.
FIG. 3 is top view of our new design for a medical instrument handle.
FIG. 4 is bottom view of our new design for a medical instrument handle.
FIG. 5 is front view of our new design for a medical instrument handle.
FIG. 6 is back view of our new design for a medical instrument handle.
FIG. 7 is perspective front to back view of our new design for a medical instrument handle; and,
FIG. 8 is perspective back to front view of our new design for a medical instrument handle.
The broken lines showing the remainder of the medical instrument are directed to environment and are for illustrative purposes only; in the drawings, the broken lines shown represent unclaimed subject matter only and form no part of the claimed design.