A wiper arm for supporting a wiper blade includes a wiper arm head comprises a recessed splined cup portion having a plurality of angularly adjacent teeth about the internal circumference of the cup portion wherein the cup portion includes a slot. A complementary drive shaft includes a splined head having teeth for mating engagement with the teeth in the wiper arm head. In order to facilitate the alignment therebetween, an integral alignment key is received in the axially aligned slots. The alignment key further includes a lower notched end which abuts against a bottom radial lip of the splined head to prevent the key from moving axially in the slots. As such, the key and the splined head include complementary formations preventing the key from accidentally falling out of the slots.