FIG. 1 is a top, front, and left side perspective view of a computer monitor support arm showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a left side elevational view thereof, the right side being a mirror image of that shown;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a top, front, and left side perspective view thereof, the broken-line disclosure fo a computer monitor being for illustrative purposes only and forming no part of the claimed design.