The Dana 44 one is held on by three studs that are in a small arc around the knuckle. The arm goes over the studs, then three cone washers go onto the studs and into the arm, then three lock nuts hold it all together.
The Dana 60 arm has four studs, one at each corner, it also holds in the kingpin spring and bushing. The arm goes over the studs and then 4 lug nuts go onto the studs to hold the arm and the kingpin spring in.
Depdog