2012 Buick LaCrosse Q&A

2012 Buick LaCrosse Question: what part is that on top of the roof.? it looks like a shark fin?

my wife was backing out of the garage and didn't allow the door to fully go up. The bottom of the door hit that "little shark fin thing" and raised it up about 1/2 inch. What is the name of that piece and is it inexpensive to repair? -
Answer 1
the thing that gives radio reception begins with an A. -