User blog comment:Morganaforever/Thoughts on Merlin's finale/@comment-5659316-20121225034939/@comment-5829707-20121225183420

I disagree with the interpretation that the arm was Arthur's because Merlin threw Excalibur into the water before placing Arthur into the boat and sending him into Avalon. The Lady of the Lake is the keeper and protector of the sword until Arthur comes back and needs it again.