口腔・咽頭の異物としての魚骨に関する研究（２）

Abstract

In recent years, seafood consumption has been declining nationwide. One of the suggested reasons for this downtrend, known as flight from fish, is the problem with throat lodgement of fish bone from seafood dish. The Pacific saury, Japanese jack mackerel, sardine, mackerel, and Japanese eel are commonly consumed fish, but their small bones tend to lodge in the throat. Here, we report the morphological characteristics of small bones of these types of fish. Twenty samples of each of the Pacific saury, Japanese jack mackerel, sardine, mackerel, and Japanese eel were purchased from fish markets during the period from January to December 2009. Abdomens of raw or cooked fish were dissected to recover small bones (ribs, epipleural, epicentral, epineural and pteygiophore). The bone samples were first subjected to softex radiography and then stained with alizarin red S. The length and diameter of these bone specimens were measured and their form were observed under a microscope. Decalcification of small bones immersed in acetic acid was observed in a similar manner. It was found that the tips of the small bones of the Pacific saury, sardine, and Japanese jack mackerel were very pointed, suggesting that these can easily damage the tonsilla palatina and lodge in the pharynx. Formation of hook-shaped lumps in their base parts were also observed, and this was considered to cause frequent deep lodgement of bones in the larynx leading to difficulties in their removal. The small bones of the Pacific saury and sardine were finer, denser and more elastic than those of the Japanese jack mackerel and mackerel, and that the small bones of the Japanese eel were sharply pointed at both ends and finer than those of the other types of fish. These results suggest that the sites, forms, and incidence of lodgement of small fish bones in the throat vary depending on the types of fish.