Getting under the hood in strut design.
A strut uses a wishbone, which gives a point to affix the hub carrier or axle... this lower arm system gives wheel location. The upper section of the hub carrier is fixed to the underside of the outer strut, enabling a sliding motion which extends upwards to a fixture in the vehicle shell. The line from the strut's top mount to the bottom ball joint on the control arm gives steering axis guidance.
If the vehicle has an anti-roll bar or swaybar, it's connected by a ball-jointed rod to the spring-damper, or by a ball or jointed rod running to the wishbone.