During the scene in which Dwight comforts Michael's burned foot with a hand-held electric fan, Michael's crutches are leaning against the wall behind Pam. At first, they are overlapped. In the next shot, they are apart. In the following shot, they are overlapped, once again.
When Jim, Dwight, and Michael are loading into Meredith's minivan to take Dwight to the hospital, Michael wants to know why Meredith drives a minivan. Jim says, "She has a kid," and Michael follows with "She has one kid and no husband and she's not going to get one driving this thing." From Episode #1.4, "The Alliance", we already know that Meredith has "two kids" according to Dwight's brief biography on Meredith as Michael tries to write something witty in her birthday card.
In the hospital the ER doctor orders Dwight a CT. Later the nurse advises that all metal needs to be removed and won't allow Michael in the CT room until he looses all metal on his personage. This wouldn't be necessary for a CT which uses X-Rays and is not magnetic. The only metal that would hinder the procedure is metal that would show in the actual image. For the example of a head scan, earrings would need to be removed.
Furthermore, the actual procedure done on Dwight is in an MRI machine which would react with metal.