The radio-opacity of fishbones--species variation.

Plain radiographs are often taken to localize fishbones which lodge in the oropharynx and hypopharynx, but which are not seen on clinical examination. Fishbones which are thus revealed can then be removed by endoscopy. For a lateral neck radiograph to be useful in excluding a fishbone when mirror examination is difficult or fails to reveal a foreign body, it is important to know which types of fishbone are radio-opaque. We used a pig's neck preparation to simulate a human neck to determine the radio-opacity of the bones of 14 different species of fish eaten in the British Isles. We conclude that only the bones from cod, haddock, cole fish, gurnard, lemon sole, monk fish, grey mullet and red snapper are well seen by soft tissue radiographic techniques.