Bump on my humerus (upper arm bone)
On my left arm, when I lay my palm face up, thumb facing left, fully extended, I can feel a bump on my humerus bone, on the ulnar side. It is NOT my elbow. The bump does not hurt, and you can't see that it's there, but if the location is pressed it can be felt. I would estimate its size to be smaller than a gumball but large enough to notice. This bump does not occur on my right arm.
I am quite thin (100lbs at 5'3") so am I just touching bone (which is creepy anyway) or have I just discovered some cancer? A nurse who examined it was unable to come to a conclusion.