A spinal cross connector head assembly and a cross connector assembly utilizing the spinal cross connector head assembly are configured for fixation to an existing spinal rod bone screw head. The spinal cross connector head assembly has one or more components which incorporate one or more breakaway portions that aid in the installation of the cross connector head assembly onto a polyaxial spinal rod bone screw assembly. The spinal cross connector assembly includes first and second spinal cross connector head assemblies each of which is configured for fixation to existing, adjacent spinal rod screw heads and connection with a cross connector rod. Each spinal cross connector rod head assembly has a dual breakaway system including a cross connector head component having a breakaway collar that, once detached, provides a polyaxial cross connector head, and a set screw component having a breakaway set screw that, once detached, provides fixation of the orientation of the polyaxial cross connector head relative to the polyaxial spinal rod bone screw head.
