Statistics from Altmetric.com
Ring pulls from aluminium cans can be swallowed or inhaled accidentally when the tab breaks off into the can and when the contents are drunk quickly.
In this case, the tab was swallowed and was thought to be stuck in the oesophagus because of local discomfort. Plain radiographs were of no help and so endoscopy was performed and the tab retrieved from the stomach using a basket.
Unfortunately x rays at energies used for standard chest and abdominal films do not show the tab as might be expected because of the low density of aluminium. It is essential therefore that in cases where there may be doubts as to whether this was actually swallowed—for example in babies, that the doctors are not lulled into a false sense of security by not seeing the tab on an x ray film.