脊椎動物鼓膜の線維構造に関する研究
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概要
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The author examined the fibrous structure of the tympanic membrane in amphibians, reptiles, birds and mammals under the microscope with a polaroid attachment. The conclusions were as follows: 1) The lamina propria of the tympanic membrane was composed of two groups of fibers, radial and non-radial. The radial fibers, could be found in all of the examined vertebrates. On the other hand, the non-radial fibers could be found in 'all vertebrates except some amphibians (Fig. 1). The arrangement of the non-radial fibers varied in different species, but had resemblance in a same species (Fig. 1∼10). 2) In mammals, the non-radial fibers consist of three sub-groups, circular, parabolic and trans- versal: The circular fibers could be divided into two types. In typeI, fibers ran in parallel with each other, while in typeII, fibers ran across to make network (Fig. 7, 14, 18). The mixture of those two types of arrangement of fibers was not observed. The parabolic fibers originated from the short process of the malleus and ran in parabolic courses forward and backward to the periphery of the tympanic membrane. The transversal fibers which were discovered in certain mammals in this study, were designated as the "transversal fiber" by the author. These fibers ran from one point in the periphery of the tympanic membrane to an opposite in the inferior area of the membrane, making arches with their concavity against the umbo (Fig. 9, 10, 20). 3) Secondi and Fumagalli discovered the "crescentic fiber" at the border of the tympanic membrane in some mammals. The crescentic fibers and the parabolic fibers were mentioned to make the " parabolic-crescentic system" (Fig. 11). Moreover, they mentioned that this system and the radial fibers were in a reciprocal balance, and with different position of the malleus, the degree of their bending would change, but not their tension. However, in this study the so-called "crescentic fiber" were not observed. Although small arches of fibers were regarded as the crescentic fibers at the border of the membranes in some mammals (ape and mankind), those fibers were confirmed to be the endings of the parabolic fib ers by the author (Fig.12, Fig.19, d). This indicates that the parabolic fibers transmit the acoustic vibration of the tympanic membrane to the short process of the malleus concentrically (Fig. 13). 4) According to the morophological observations above mentioned, the author assumed that the difference in the mode of vibration of the tympanic membrane depended upon the difference in the structure of the fibers of the tympanic membrane. This assumption was assertained in this study by means of a stroboscope (Fig. 15, 16).
- 一般社団法人 日本耳鼻咽喉科学会の論文