Here is a function I have used for similar things. Maybe it will work.
function [circlesx, circlesy]=drawCircle(axes_handle,x,y,radius,npoints,c);
angles=0:(2*pi/(npoints-1)):2*pi;
circlesx=radius*cos(angles)+x;
circlesy=radius*sin(angles)+y;
patch(circlesx,circlesy,c);