For no solution, the two lines have to never intersect, which means they have to be parallel lines. In other words, no solution will satisfy both equation. For infinitely many solutions, the two lines have to overlap each other, which means one equation has to be a multiple of the other equations.
[joint] the site of the junction or union of two or more bones of the body; its primary function is to provide motion and flexibility to the frame of the body. Some are immovable, such as the sutures where segments of bone are fused together in the skull.
The temporal bone is a very thick and hard structure located in the base of the skull. The base of the skull has multiple foramina, as seen in the images below, creating areas of decreased resistance susceptible to traumatic injury.