Thumbtack in Bronchus
How many of us have held a thumbtack between our lips, while hanging posters on the wall? Standing on bed railings or balancing on a mattress increases the risk of gasping and inhaling a thumbtack into a bronchus. (Standing on a ladder while holding a nail between one’s lips would be about as dangerous).
Only the metal portion of the thumbtack is seen on standard xrays. As usual (because of aerodynamics), the tip of the pin points upward.
Please also view the final image, drawn in chalk by Dr. Chevalier Jackson, at age 71, many years ago.
The tip of the thumbtack is grasped with a optical ("toothed") alligator forceps