The radio-opacity of fishbones: a cadaveric study.

Lateral neck radiographs performed to localize impacted fishbones have a low sensitivity. The differing radio-opacities of the bones of various fish species may be a reason for this. A cadaver head and neck and the rib bones of 10 species of fish were used in this study. A laryngoscope was used to introduce a fishbone into the vallecula and then into the hypopharynx of the cadaver. A lateral radiograph was taken in each case. Ten control films were taken. The radiographs were independently reviewed by a consultant radiologist and otolaryngologist. The presence and position of any bone seen was noted. There was no inter-observer variation. All species of fishbone were visible. One bone was not seen by either observer. Visualization of fishbones is more dependent on position than their degree of radio-opacity. Routine radiography is recommended.