FIG. 1 is an isometric view of a mounting arm for a monitor showing my new design in a partially open, articulated position;

FIG. 2 is an isomentric view of my new design in a closed position;

FIG. 3 is a front elevation of my new design in a closed position;

FIG. 4 is a left-side elevation of my new design in a closed position;

FIG. 5 is a right-side elevation of my new design in a closed position;

FIG. 6 is a top plan view of my new design in a closed position;

FIG. 7 is a bottom plan view of my new design in a closed position; and,

FIG. 8 is a rear elevation of my new design in a closed position.

The broken line showing of supporting structure is for illustrative purposes only and forms no part of the claimed design.